BEST WAYS TO POLLINATE PEACH TREES

Peach trees (Prunus persica) begin to bear fruit at 3 to 4 years of age. The health of the tree, the environment, weather, and pollination are all factors in bearing fruit. Disease and insect damage affect fruit quality and extreme weather may cause bud drop, and without successful pollination there will be sparse fruit on the tree.

FIG: PEACH ORCHARD

Types of Pollination

Fruit trees are categorized as self-fruitful or selfunfruitful. Most varieties of peach trees are self-fruitful and do not need another tree of the same type to create pollination. Self-unfruitful cultivars of peaches are "J.H. Hale," "Earlihale," "Hal-Berta," "Candoka" and "Mikado." When these varieties are planted near any other variety of peach tree, they become fertile. Trees such as apple, pear, plum and cherry pollinate successfully when grown near others of the same species. There are individual variations within varieties of each type of tree.

Fertilization

Self-fruitful peach trees have male and female parts within each flower. Grains of pollen are transferred from the anthers (male floral part) to the stigma (female floral part). The sticky surface of the stigma catches the pollen. Pollen germinates and a tube grows to unite it with a female cell in the flower ovary. Fertilization occurs, a seed develops and fruit begins to enlarge. Cold and hot weather extremes affect developing peach buds. An extended midwinter warm period causes loss of the cold hardiness that stimulates fruit development. Temperatures below 30 degrees Fahrenheit also damage bud development.

Best Cultural Practices for Pollination

Peach trees pollinate successfully when given adequate sunlight, water and nutrients. Plant peaches in full sun where they are not shaded by buildings, fences or large trees. Do not plant in areas where roots will compete with shrubs or other tree root systems. Peach trees need 13 minerals from the soil to maintain health. The nutrient content of soil is maintained by using mature compost yearly as fertilizer. Peach trees also benefit from a layer of straw, shredded bark or leaves as mulch. Spread a 3- to 4-inch layer of mulch around the tree to keep soil warm, reduce weed growth and conserve water.

Pruning and Watering

Well-pruned and maintained peach trees pollinate and produce good quality fruit. Cut off all diseased, broken and crossed branches in late winter before the buds begin to swell. Cut each branch back by 1/3 and remove branches that are too low to the ground. Pruning improves air circulation and light availability. Un-pruned tree limbs become weak and spindly, producing less fruit. Pruning makes the limbs grow larger and stronger. Irrigate peach trees weekly during the growing season as they develop fertilized blossoms and young fruit.

SUSHIL KUMAR IS NOW A LAKHPATI FARMER, THANKS TO VEGETABLES PEA

Mr. Sushil Kumar Bind is a marginal farmer in village Bahuti, block Marihaan District Mirzapur, Uttar Pradesh. He has about one hectare land for cultivation. Earlier, he was a worried farmer and was unable to fulfill his family’s requirement. A transformation happened in his life when he attended Kisan Mela at the Indian Institute of Vegetable Research (IIVR), Varanasi and interacted with the vegetable scientists. He came to know about early varieties of vegetable pea matching very well in rice-wheat cropping system prevailing in eastern parts of UP. Further, help was provided to him under the NAIP Sub Project- livelihood security in disadvantaged districts of Purvanchal. Under the project, he obtained quality seeds and fertilizer.

He initiated vegetable cultivation under the supervision of scientists of IIVR. Scientists of IIVR told him to cultivate pea in his whole land, he agreed. He began with land preparation, first of all, he examined his land and did deep plowing of the farmland. He applied organic fertilizer (Gobar Khad) and irrigation of his land to destroy unnecessary weeds and pests. After land preparation, he did seed sowing of Kashi Uday and Kashi Nandini in the last October. Seeds germinated very soon. He started taking care of the plant and destroyed all unwanted weeds. After one month, flower blooming started and fruiting started profusely. Mr. Sushil Kumar Bind started picking peapods in the month of December and sold to the market @ of 25-35 Rupees per kilogram. In the month of December, he earned about Rs. 40.000 by sale of 1200 kilograms of pea pod.

In the month of January, production of the crop was very high and through four picking of pods, he collected about 3500kg fresh pea pods. At that time he earned about 57,500 rupees by selling produce @ Rs.15-20 per kg at Mandi.

In the month of February, the price of pea pods declined, so he did only two pickings of pea pods. He harvested about 1500kg and sold it @ 5-10 Rs. per kg and got about 11,250 rupees. After that, he left the crop for seed production. At last, he collected about 2500 kg in the form of seed. He earned another 15,000 rupees by the sale of seed.

pea.Mr. Sushil Kumar has earned approximately 1,23,750 rupees by sale of pea. He spent 5000/- on seed, 10000/- on transportation, 1000/- on irrigation and 2000/- on land preparation and 5000/- for fertilizer. In brief, he spent about Rs. 23000/- and earned about one Lakh Rupees in a short time period by cultivation of pea. Now, he is planning to cultivate sweet pea in his whole land. He is regularly in touch with vegetable scientists for getting more information. He also motivates other farmers for vegetable cultivation.

Indian Institute of Vegetable Research, Varanasi has brought prosperity to Purvanchal farmers through the cultivation of vegetable pea. Scientists of IIVR have done rigorous experiment on vegetable pea and developed two high yielding varieties Kashi Uday and Kashi Nandini. These varieties are not only early but having high yield also. Kashi Uday gives production about 750-900 kg/hectare whereas yield potential of Kashi Nandini is about 900-110kg/hectare. These varieties possess a high degree of disease resistance also.

Article Written By -Dr. Shubhadeep Roy (Scientist, IIVR)

Altered sex expression by plant growth regulators in bitter gourd .

Fig:- Female Flower

Fig:- Male Flower

Bitter gourd is one of the popular vegetables for its medicinal values. It is monoecious cucurbitaceous

plants that have an imbalance sex ratio of male-female flowers that causes lower fruit yield. Different

research works on cucurbits like bitter gourd and other related crops in respect of plant growth regulators, plant nutrients, and priming practices have been conducted in different parts of the world. Literature related to the present study has been reviewed and found that bitter gourd genotypes produced larger male-female ratio and the induction of male flower was earlier than that of female ones. Growth regulators have a significant positive effect on yield and yield components. Application of gibberellic acid (GA3) enhanced the length of the main vine but decreased the primary branches while ethylene producing chemicals Canadian Environmental Protection Act (CEPA) increased the number of primary branches per plant. Application of auxin like 1-naphthaleneacetic acid (NAA) at 50 and 100 ppm and CEPA at 150 ppm also proved to be effective in inducing earlier female flowers at lower node. Application of CEPA at 150 ppm and NAA at 50 ppm was found to be the best treatments for reducing sex ratio by increasing the female flowers by suppressing the male ones and consequently induce higher yield.

Table 1: Effect of different levels of plant growth regulators and NPK fertilizers on sex expression in bitter gourd.

Table 2. Interaction effect of different levels of NPK fertilizers and plant growth regulators on initiation of first flower (male and female) grown in summer

*No. of days after sowing of seeds. F: Effect of different levels of NPK fertilizers. PGR: Effect of different plant growth regulators. F × PGR = Interaction effect of different levels of NPK fertilizers and plant growth regulators. CV: Coefficient of variance.

Conclusions

Among the many factors which determine the low yield, sex ratio and synchrony of male-female flowers and suitable genotype are more important. Days to first flower initiation, number of total female flower and sex ratio was significantly influenced by different genotypes. The days to first male and female flowers varied from 39.4 to 51.17. The results indicated that the days to flower initiation might be controlled by inherent characters of genotypes.

Application of different doses of plant growth regulators and NPK fertilizer significantly influenced the female flower induction and synchrony of male-female flowers. Application of CEPA at 150 ppm and NAA at 50 ppm produced a lower sex ratio by increasing the female flowers by 40 and 28% over control (no spray). Among the plant growth regulators, CEPA is the superior of all for producing the maximum number of female flowers plant-1. On the other hand, the combined effect of treatment

Grapes Training & Pruning

                            

DIFFERENT SYSTEM OF TRAININGS OF GRAPES:-

BOWER SYSTEM: In this system criss-cross network of wires is made about 2.1 x 2.4 m on the pillars with holes at 60cm apart. The vines are allowed to grow up to the height of the wires either by stacking or tying, two primary branches with three secondaries on either side are allowed to grow so that each result into twelve secondaries are developed on reaching the height of wires. Vines are then pinched off to produce side shoots. These secondaries are then produced 8-10 tertiaries to fruit or to form the fruiting canes.

KNIFFIN SYSTEM:   Here, 2 trellis of wires are strung supported by vertical posts. The vine is trained so that it bears 4 canes one along each wire and bearing shoots can hang freely. In this system, 2 wires are stretched horizontally at the height of 0.90m and 0.60m.height. Vines are planted at 2-4m.distance between 2 poles supported by sticks to allow single stem to grow with one arm horizontally to either side so that each arm having with the results into 4 arms.

TELEPHONE SYSTEM:  Under this system, ‘T’ trellis is used with 3 top wires on ‘T’ shaped supports which looks like a ‘Telephone pole and wires’. Here, primaries are developed to grow from the main stem. From these primaries, short secondaries of 30-45cm are developed on both the side at an irregular intervals forming an umbrella type of framework. These secondaries are developed the fruiting canes. 

TATURA TRELLIS OF ‘V’ / ‘Y’- TRELLIS SYSTEM:- 

 This is suitable for vigorous vines. Here, trellis are fixed in rows at a distance of 25 cm. The length of ‘Y’ is 1.2 m. The angle between two arms of ‘Y’ is 100 - 110⁰ and length of arm is 90 – 120 cm. Here, two rows of cordon wires are developed with a gap of 50 cm. The number of cordon can be one/two as per the choice of the grower and vigour of the vines. It is better to provide two rows of cordon in vigorous vines. Three foliage wires are run across the each sloping arm with  a gap of 30 – 35 cm. Rows of sloping arms are interconnected by a thick wire, across which run two more wires to support the foliage. Hence, under this system between the two rows, a narrow bower is formed.

CORDON SYSTEM: -Under this system of training to get better exposure of  sunlight, the vines are planted obliquely at an angle of 45⁰. The plants are supported by wires and stretched  tightly along the direction of the rows. Here, wires are placed to a height of 0.8 – 1 m, 1.5 –1.7 m. and 2.5 – 3m. above the ground level. In the cordon system of training, generally the main trunk of the vine is allowed to developed up to a height of 3 m (i.e. position of the last wire is stretched ) which carries the fruiting spurs on attaining to the different height of the wires, either one shoot from the main trunk is trained to extend horizontally on one side of the wire trellis, i.e. unilateral horizontal  cordon or two shoots are trained to extend i.e. bilateral horizontal  cordon is developed.

GROWTH HABIT OF GRAPEVINE :  Branching habit -  ‘ Helicoid’ i.e. every alternate bud will be on one side of the cane. In a growing state, the first, third and fifth terminal buds will grow on one side, while the second, fourth and sixth buds will be grown on the opposite side of its earlier nodal growths.          

Effect of training and pruning on vine’s growth : - While trains the vine, vines are   slowly  developed to cover the whole structure of the  training system with primary, secondary and  tertiary growth of such vine branches to get a  maximum fruiting zones on canes or spurs of a  vine. It is possible through pruning and training  process followed over a period  of years. Otherwise, if the vines are not pruned properly it will remain unproductive and will produce fruiting  wood at the apical ends of the vine with few fruitlets only(it is due to Apical Dominance.)Therefore, these two cultural operations or practices are more important in viticulture.

PRUNING:-The time of pruning in grapes depends on :

(I). Type of annual growth cycle of the vine.

(II). Prevalent climatic condition of the planted area.

Pruning  A/C Climatic zones:-

 1. Temperate climate zone:- During dormant period of the vine i.e. in winter (January) Forward/winter/ Pruning for cropping.(SINGLE PRUNING FOR SINGLE CROP).

 2.  Subtropical climatic zone:-  Pruning is done like temperate zone in February – Forward/winter/ Pruning for cropping.(SINGLE PRUNING FOR SINGLE CROP).

 3. Tropical climate zone:- Vines do not undergo dormancy. It grows continuously round the year. Pruning done once a year in summer (March- April) – Foundation / Back/Growth/Summer Pruning and again in September --  November- Forward / Pruning for cropping.(DOUBLE PRUNING FOR SINGLE CROP).

4. Low latitude of winter less tropical zone:-  Temperature remains higher in all the year-round. Pruning done like Tropical climatic zone.

Manipulating of pruning practice is done here for getting 2 crops in a year.

Once in May—November and again in November– January.  (DOUBLE PRUNING FOR DOUBLE CROPS).

BUD BREAK:- In temperate climatic conditions after ‘Forward Pruning’,  treatments are given to the top buds of the pruned vines, to sprout them in a maximum way through –  1. Cane twisting, 2. Thiourea (3-4.5 %) treatment by smearing the buds, etc. are important.

Apple Breeding , Approaches & Applications.

Apple is known as the king of temperate fruits / symbol of health/premier fruit of the world. Cultivated apple Malus X Domestica are diploids (2n =34) and few are triploid (2n=51) and ancestor of it is Malus sylvestris. Apple originated from Southwestern Asia and belongs to family Rosaceae subfamily Pomoideae. It is a deciduous fruit tree mostly grown in temperate region of the world. It is a deciduous fruit tree mostly grown in temperate region of the world.

OTHER SPECIES

• Sucker free species - Malus siversii
• Apomixis species - Malus sieboldii
• Indigenous to Himalayas - Malus baccata var himalacia , M. sikkimmensis
• Resistant to scab - M. floribunda , M. atrosanguina
• Resistant to powdery mildew and Codling moth - M. zumi
• Resistant to woolly apple aphid - M. hupehensis

BREEDING OBJECTIVE

1. Since Apple is a composite tree consisting of rootstock and scion, there is also need to develop rootstock with the aim to manipulate growth, suitable for a specific location as well as for good reproductive ability.

2.To involved varieties red in colour with early maturity, high yield, superior dessert and storage quality and resistant to diseases(scab) and pests

ROOTSTOCK BREEDING

• To develop woolly apple aphid resistant rootstock using a Northern Spy as a source of resistance
• To focus on productiveness and tree size control
• Adaptation to soil and pest problems
• It shows considerable resistance to crown rot and winter hardy like P-1, P-2, P-16, P-22 from M-4 X Common Antonovka

Recent Rootstock Research Comprises:-

i. Development of new dwarfing, winter hardy, efficiently cropping clones, using cross-breeding technique

ii. Evaluation of recently developed dwarfing rootstocks of Czechslovakia and USSR origin.

The present breeding programme is with primary focus to study the genetics on heritability of vigour, rooting, feathering, earliness of bud break and efficiency of cropping.

Evaluation research is mainly aimed to test the efficiency of propagation, influence on the growth of a cultivar, precocity of bearing, cropping efficiency and resistance to pests and diseases

SPECIAL FEATURES OF ROOTSTOCK AND IT’S CHARACTERISTIC

BREEDING OF SCION CULTIVAR

Fruit appearance -fruits should have attractive good colour, a regular shape

Northern spy, cv like Jonagold and Elstar

Fruit size – 65 mm diameter is generally

of 65-75 mm dia eg : triploid var like Crispin, Holstein , Jonagold etc

Eating quality – prefers cv having medium

16%).

Fruit color-Europe – Golden delicious, jonagold, Elstar

North American –Golden delicious, Red delicious, Mc Intosh (low acid/ low sugar and

good culinary apples)

India –Red delicious, Royal delicious

Yield – it should have high yield cv like

• Pest and disease resistance viz Malus floribunda, Malus zumi, Malus hupehensis

• Early maturity and have long shelf life.

• Cold hardiness – Honeycrisp, Lobo, Katjo, Mantet, Fireside, Wealthy, Yellow Transparent

• Winter chilling requirements – Anna, Einshemer , schlor , Mollie delicious, Adina

• Season of flowering – late flowering considered as the best as it avoid from disastrous spring fros

• Duration of juvenile period

• Season of ripening

• Compact columnar cultivars, new cultivar which has been selected at East Malling can be grown as natural

cordons without pruning.

• Mutation breeding, isolation of spontaneous somatic mutations in a

production of new apple

cultivar eg Dutch plantation of Elstar shows more coloured than its mother tree

Limitation in Conventional Breeding

• Slow and lengthy.
• Long juvenile period.
• Self incompatibility.
• Polygenic control of most of the
• Large population required to recover

Floral biology:-

Fig:- Floral diagram

Flowers of apple cultivars and seedling vary considerably in shape, size and in colour from white to deep pink. They are borne in cymose clusters on fairly short pedicels, usually on spur type growth. but in some instances from terminal or lateral buds of the previous season’s growth. The typical flower consists of 5 petals, calyx of 5 sepals, about 20 stamens and pistil which divides into 5 styles. Ovary has 5 carpels, each usually containing seed content is 10 but some cv have more Northern spy usually have 12 to 18 seeds and Ottawa 3 rootstocks often has 20 to 30 seeds

Pollination:- Cross-pollination mainly done by insect particularly bees.

Some cultivars act as pollinizers are :

Tydeman’s Early Worcester: One of the earliest varieties and act as pollinizer for Delicious varieties.

Lord Lambourne: Hybrid between James Greeves x Worcester Peermans’s.

Granny Smith, Red Gold, Golden Delicious YellowNewton, Mc Intosh, Early Shanburry , Winter

Banana, Starkspur Golden, Golden Spur.

Methods of Crop Improvement

Introduction:-In apple lots of emphasis laid on introduction and selection during last decades. Apples are introduced for different purpose such as :

a) spur type cultivar - At regional research station , Mashobra (H.P), 12 varieties are

introduced through NBPGR New Delhi in 1980 Red spur delicious, Golden spur delicious,Oregon spur, Red chief, Miller, Sturdee spur,white spur , Stark crimson

b) Colour spots – Royal red , Vance delicious. Top red, Skyline supreme, Red Delicious

c) Low chilling variety – Introduced through NBPGR to RRS , Phagi , Shimla Vared, Michael , Tropical beauty, Parlin beauty, Mayan, Schlomit, Hybrid-1

d) Scab resistant var – Prima , Priscilla , Liberty, Florina, Macfree, Freedom, Coop-12

e) Early maturing var – Yandik onskoe , Papisonka canninga Introduced through NBPGR , New-Delhi.

• Of the scab resistant variety co-op-12 has shown better performance as an Early subacidic variety whereas Florina promised as a coloured sweet varieties

however none of these compared favourably well with popular delicious and its commercial spots, it is therefore logical that some of these tracts are incorporated in our commercial variety.

• Sufficient attempt have not been made to introduced low chilling apple cv in N.Indian plains and South India .

• From early introductions cv such as Tropical beauty and Perlin beauty were found to be best w.r.t.

productivity and fruit quality

• Some cv of Sub – Tropical apples are Maayan , Michael, Schlomit and Vared where introduction from Israel and are under evaluation.

Selection:-

• In Horticultural Experimental Station (TNAU) in Kodaikanal selected 1 variety i,e KKL-1 called as

Kodaikanal beauty , this is a selection from Parlin beauty

• Many of existing commercial cv which originated as chance seedlings are Golden Delicious, Baldwin and Granny Smith.

Hybridization:-

Apple improvement work has been going on (a) The Regional Fruit Research Station Mashobra, H.P.(b) F.R.S., Shalimar, J and K.(c) Horticulture and Experimental Training centre, Chaubattia, U.P.

Resulting in a no. of release of new varieties, work was initiated in Kashmir (1956) to combine high dessert quality of delicious group with good keeping quality of Ambri.

• Two hybrids such as Lal Ambri and Sunehri were released

• Similarly work has been also initiated in H.P. (1960) as a result hybrids Ambred ,Ambstarking and Ambrich have been developed . Subsequently hybrid, Ambroyal was also developed.

• Work on apple improvement was started at Chaubattia (1970 ) to developed Early maturing cultivar with good dessert quality.

• Two promising hybrids were involved Chaubattia Princess and Chaubattia Anupam

• Some crosses were also made to developed scab resistant cv

• Two outstanding hybrids Firdous and Shireen were developed to adaptation.

• Variety developed with parentage and important characters are as follows :

1. Jammu and Kashmir

Lal Ambri – Red Delicious X Ambri , Ambri with red colour

Sunehri – Ambri X Golden Delicious , Ambri with colour of Golden Delicious

2. Himachal Pradesh

Ambred – Red Delicious X Ambri-57 ,keeping quality good, low incidence of powdhery mildew , soothy blotch and scab.

Ambstarking – Starking Delicious X Ambri-81 , tolerant to scab

Ambroyal – Starking Delicious X Ambri-84 ,semi dwarf tree , semi spur type and having good dessert quality

Ambrich – Richared X Ambri-15 , semidwarf, semi spur, good dessert quality,tolerant to scab.

3. Chaubattia, U.P

Chaubattia Princess – Red Delicious X Early Shunberry, early ripe in last week of June, fruit with deep red streaks on pale background, very sweet and good keeping quality.

Chaubattia Anupam – Red Delicious X Early Shunberry, ripen in second week of July , fruit skin with shiny red streakes with red blush on pale background Inheritance of traits A no. of important horticultural traits are controlled by major genes and therefore incorporated in breeding programme for the development of new cvs . large no. of important characters of apple under polygene control

Powdery mildew single major genes PL1 and PL2, M. zumi and M. robusta. M. hupehensis has been reported to transmit resistance to woolly apple aphid and resistance to codling moth is incorporated from M. zumi.

Mutation Breeding:-

A bud sport is a mutation arising in a cell from which a bud developed. It affects growth habit particularly the spur or compact type which produce compact or Dwarfish. This is the basis for bud selection to maintain the integrity of the cultivar. The rate of single gene mutations can be increased by irradiation with X- ray, Gamma ray and thermal neutrons

Bud sport – due to mutation , Red Allister/ Red Elster ,natural mutant of allister

• Vance Delicious : Bud mutant of Delicious.

• Top Red : Bud sport of Shot Well Delicious

• Skyline Supreme Delicious : Bud mutant of Starking Delicious.

• Gold Spur Delicious : Bud mutant delicious Delicious. This variety is recommended as

pollinizer for all spur types.

• Red Spur Delicious: It is a variant tree in Starking Delicious orchard.

• Red Chief: Bud sport of Delicious.

Sterility and Incompatibility

• These are the two main causes of unfruitfulness in apple
• Apples has Gametophytic incompatibility whereby the pollen tube growth is arrested in the style
• Variety like Cox’s orange pippin , Golden russet and Northern spy. Apomixis
• Facultative apomixes is characteristic of a number of Malus spp that are probably of hybrid origin but does not appear to occur among the cultivated apple.
  

Meadow Orcharding in Guava Fruit Production

Meadow Orchard System is a new concept of guava planting which has been developed for the first time in India at Central Institute for Subtropical Horticulture, Lucknow. The planting is done at 2.0 m (row to row) x 1.0 m (plant to plant), which gives a density of 5000 plants per ha. The trees are pruned and trained to allow maximum production of quality fruits during the first year. A single trunk tree with no interfering branches up to 30 - 40 cm from the ground level is desirable to make dwarf tree architecture. After a period of 1-2 months of planting, all the trees are topped at a uniform height of 30-40 cm from the ground level for initiation of new growth below the cut ends. This is done to make a single trunk straight up to 40 cm height. After 15-20 days of topping, new shoots emerge. In general, 3-4 shoots are retained from below the cut point after topping. As shoots mature generally after a period of 3-4 months, they are reduced by 50 per cent of their total length so that new shoots emerge below the cut point. This is done to attain the desired tree canopy architecture and strong framework. The emerged shoots are allowed to grow for 3 - 4 months before they are again pruned by 50 per cent. After pruning, new shoots emerge on which flowering takes place.It is emphasized that shoot pruning is done thrice a year. This leads to desired canopy development. Though fruiting starts, in the same year, one can not expect fruits on each and every shoot. Pruning is continued so that plants remain dwarf. After a year, pruning operation is done especially in May-June, September-October and January-February.Harvesting of fruits is generally done in January-February from the May-June pruned shoots. After harvest, the pruning is done above fruiting points. New shoots emerge after pruning of shoots during January-February. On these shoots, flowering takes place and fruiting is obtained during July-September. Second time pruning is done in May-June. After pruning, once again shoots emerge and flowering takes place, which yields fruits during December-February. These shoots are further pruned for the third time in September - October. This is the technique for maintaining a meadow orchard for optimum production and dwarf tree size. The height of plants is restricted to 1.0 m, while an average production of 10-12 kg fruits plant-1 is obtained every year. As harvesting is easy in a meadow orchard, no damage occurs to the fruits. Seven guava varieties, viz. Allahabad Safeda, Sardar, Shweta, Lalit, CISH-G-5, CISH -G-6 and hybrid (Lalit x Shweta) evaluated under meadow orchard system showed positive impact of the technology.

Postharvest Handling Practices and Treatment Methods for Tomato Handlers in Developing Countries

Some Post-harvest Handling Practices for Tomatoes

Physical handling can have a drastic effect on the postharvest quality and shelf life of most harvested fruits and vegetables. For instance, rough handling during harvesting and after harvesting can cause mechanical injuries which can affect the postharvest quality and shelf life of harvested fruit like tomatoes [16]. It is therefore important to know suitable postharvest handling practices needed to maintain the quality and extend the shelf life of harvested tomatoes for producers in developing countries. Some of the handling practices which include harvesting, precooling, cleaning and disinfecting, sorting and grading, packaging, transportation, and storage are discussed below.

Harvesting

The physiological maturity of any fruit at harvest has an important effect on postharvest quality of that fruit [17]. Therefore, care must be taken as to when to harvest the fruit in order to attain the best quality. The shelf life of fruits and vegetables is described by postharvest physiologists in three stages: the maturation, ripening, and senescence stages. The maturation stage gives an indication of the fruit being ready for harvest [18]. Tomatoes can be harvested in either matured green, partially ripe, or ripe state. Tomato being a climacteric fruit can be harvested at the matured green state allowing ripening and senescence to occur during the postharvest period of the fruit. Producers targeting distant markets must harvest their tomatoes in a matured green state [19]. Harvesting tomatoes in matured green state will not only give producers ample time to prepare the fruit for the market but also prevent mechanical injuries during harvesting. Unfortunately, most producers from developing countries especially those in Africa harvest tomatoes when they are partially or fully ripened . Fully ripened tomatoes are susceptible to mechanical injuries during harvesting resulting in shorter shelf life. Care must therefore be taken when harvesting tomatoes in ripe state to avoid these injuries which will hasten deterioration. Also, the use of harvesting and packaging containers with sharp edges must be discouraged to prevent bruising and puncturing of the fruits. Harvesting of fruits should be done in either early or late hours of the day to avoid excessive field heat generation. The inability of producers to follow these simple but vital harvesting procedures coupled with some inefficiencies (like lack of ready market and processing facilities) in the entire value chain may explain the reasons why there are lots of losses in tomatoes harvested at fully ripened state in most developing countries. Access to ready market is a big challenge when dealing with highly perishable crops like tomatoes in most developing countries. This challenge can be attributed to many factors but the major factor is the pattern of production resulting in high gluts. In most developing countries, a greater proportion of tomato production is rain fed. This causes high peaks in production during the raining seasons which is always more than the local consumption of the crop. The problem is further compounded by the lack of processing facilities or equipment which can be used to process the crop into a more durable form for later use. Processing tomatoes into a more durable form will also serve as a means of value addition which will finally give a better market value for the crop. Producers from developed countries always have supply contracts with multinational supermarkets to supply tomatoes. For instance, Blush Tomatoes, a tomato producing company in Australia, supplies Coles and Woolworth supermarkets with tomatoes making access to market already predetermined . In the case of producers in many developing countries, there is lack of communication between producers and consumers and also lack of market information. This could be the main reason for the mismatch between production and available markets. Producers therefore have to sell their harvest at very low cost to prevent total loss.

Precooling after Harvest

Field heat is usually high and undesirable at harvesting stage of many fruits and vegetables and should be removed as quickly as possible before any postharvest handling activity . Excessive field heat gives rise to an undesirable increase in metabolic activity and immediate cooling after harvest is therefore important. Precooling minimises the effect of microbial activity, metabolic activity, respiration rate, and ethylene production, whilst reducing the ripening rate, water loss, and decay, thereby preserving quality and extending shelf life of harvested tomatoes. The suitable temperature range of about 13–20°C for tomato handling can be attained either in the early hours of the morning or late in the evening . Harvested fruit must be precooled to remove excessive field heat if harvested at times other than the recommended periods. A cheap but effective way of precooling harvested tomatoes for producers of developing countries can be by dipping fruits in cold water (hydrocooling) mixed with disinfectants such as thiabendazole and sodium hypochlorite if availability of clean water is not a challenge. This method is effective in removing field heat whilst reducing microbial loads on the harvested fruits. Tomato producers in developing countries especially those from Africa assemble their harvested produce under tree shade in an attempt to reduce field heat. Tree shade, however, is not a reliable and effective way of reducing field heat in harvested produce. Arah et al. therefore suggested that the adoption of a simple on-farm structure like a small hut made of thatch can be very beneficial in precooling of harvested tomatoes.

Cleaning or Disinfecting

Proper hygiene is a major concern to all produce handlers, because of not only postharvest diseases, but also incidence of food-borne illnesses that can be transmitted to consumers. According to a report by the Government of India , Salmonella, Cryptosporidium, Cyclospora, and hepatitis A virus are some examples of disease causing organisms that have been transmitted to consumers through fresh fruits and vegetables. Unfortunately, cleaning or disinfecting tomatoes after harvest is not a common practice for most tomatoes handlers in developing countries especially those from Africa. This practice may be attributed to either the unavailability of portable water at the production sites or the sheer ignorance of the practice. However, in places where water is not a constraint, the use of disinfectants in water either for washing or for cooling can reduce both postharvest and food-borne diseases in fruits and vegetables. The use of various disinfectants during postharvest treatment of tomatoes is well documented. For instance, sodium hypochlorite solution has been used to sterilise tomato fruits in order to reduce the incidence of fungal infection before any postharvest treatment was applied. Dipping of tomato fruits in thiabendazole solution reduced the microbial load on the fruits. Fruits and vegetables are usually treated with chlorinated water after washing to reduce the microbial load prior to packaging. Workneh et al. indicate that anolyte water dipping disinfection of tomatoes not only reduced the microbial loads on the fruits but also maintained superior quality of tomatoes during storage. Disinfection can be used in conjunction with hydrocooling to achieve the purpose of reducing excessive field heat and reducing microbial infection at the same time.

Sorting and Grading

One of the most important processes in packaging and marketing of fruit and vegetables is sorting and grading. Sorting is the removal of rotten, damaged, or diseased fruits from the healthy and clean ones. The damaged or diseased fruits can produce ethylene in substantial amounts which can affect the adjacent fruits . Grading is also the process of categorising fruits and vegetables on the basis of colour, size, stage of maturity, or degree of ripening. The two processes are vital in maintaining postharvest shelf life and quality of harvested tomatoes. Sorting limits the spread of infectious microorganisms from bad fruits to other healthy fruits during postharvest handling of tomatoes. Grading also helps handlers to categorise fruits and vegetables in a given common parameter which enables easy handling. For instance, grading on the basis of colour or maturity stage will help eliminate overripe fruits which will easily produce ethylene to hasten the ripening process in the whole batch. Commercial tomato producers normally use sophisticated systems that require precise sorting and grading standards for their produce. Small-scale producers and retailers in developing countries in contrast may not use written down grading and sorting standards; however, the produce must still be sorted and sized to some degree before selling or processing it.

Packaging

Packaging is also one of the important aspects to consider in addressing postharvest losses in fruits and vegetables. It is enclosing food produce or product to protect it from mechanical injuries, tampering, and contamination from physical, chemical, and biological sources. Packaging as a postharvest handling practice in tomato production is essential in putting the produce into sizeable portions for easy handling. However, using unsuitable packaging can cause fruit damage resulting in losses. Some common packaging materials used in most developing countries include wooden crates, cardboard boxes, woven palm baskets, plastic crates, nylon sacks, jute sacks, and polythene bags. Most of the abovementioned packaging materials do not give all the protection needed by the commodity. Whilst the majority of these packaging materials like the nylon sacks do not allow good aeration within the packaged commodity causing a build-up of heat due to respiration, others like the woven basket have rough surfaces and edges which cause mechanical injuries to the produce. The wooden crate and the woven palm basket are some of the common packaging materials used in many developing countries especially those in Africa for packaging tomatoes. The major shortcoming of the wooden crate is in its height which creates a lot of compressive forces on fruits located at the base of the crate. These undesirable compressive forces cause internal injuries which finally result in reduced postharvest quality of the tomatoes. There have been suggestions of modifying the wooden crate to make it more suitable for packaging tomatoes. Kitinoja has therefore suggested that the depth of the crate should be reduced considerably to reduce the build-up of compressive forces which can cause mechanical injuries to fruits at the base of the crate after packaging. The palm woven baskets used by tomato handlers have sharp edges lining the inside which puncture or bruise the fruit when they are used. It has also been recommended by Idah et al.that woven palm baskets should be woven with the smooth side of the material turned inward.

Storage

Tomato has very high moisture content and therefore is very difficult to store at ambient temperatures for a long time. Meanwhile, storage in the value chain is usually required to ensure uninterrupted supply of raw materials for processors. Storage extends the length of the processing season and helps provide continuity of product supply throughout the seasons. For short-term storage (up to a week), tomato fruits can be stored at ambient conditions if there is enough ventilation to reduce the accumulation of heat from respiration. For longer-term storage, ripe tomatoes can be stored at temperatures of about 10–15°C and 85–95% relative humidity . At these temperatures, both ripening and chilling injuries are reduced to the minimal levels. These conditions are also difficult to obtain in most tropical countries and therefore losses of appreciable quantities of harvested tomatoes have been reported . This is consistent with the claim that the quality of tomato is compromised when exposed to high temperatures and high relative humidity . Very low temperature storage too is detrimental to the shelf life and quality of many tropical fruits like tomatoes. For instance, refrigerating a tomato will reduce its flavour, a quality trait of tomatoes which is largely determined by the total soluble solids (TSS) and pH of the fruit . An understanding of the correct temperature management during storage of tomatoes is vital in extending the shelf life of the fruit whilst maintaining fruit qualities. Tomatoes handlers in tropical countries can store tomatoes for short to intermediate time by using evaporative cooling system made from woven jute sacks.

Transportation

In most developing countries, the production sites for many tomato producers are far from the marketing centres and also inaccessible by road. Transporting harvested tomatoes to the market on such bad road network and the lack of proper transportation like refrigerated vans become a big challenge for both producers and distributors . This challenge therefore causes unnecessary delays in getting the produce to the market. Meanwhile, any delay between harvest and consumption of tomatoes can result in losses . Losses of up to about 20% are incurred by producers due to transportation delays . Producers will therefore make use of any available means of transport for their produce without considering its appropriateness in order to avoid delays. Some modes of transportation include human labour, donkeys, public transport, rented trucks, busses, lorries, fuel tankers, articulator trucks, and pick-up vans . However, the use of appropriate transportation for tomatoes is a major factor to consider in postharvest handling of the fruit. During transportation, the produce should be immobilised by proper packaging and stacking to avoid excessive movement or vibration. Vibration and impact during transportation as a result of undulations on roads are one of the major causes of postharvest losses to most fruits and vegetables especially tomatoes . The bad nature of road networks in most developing countries therefore provides these unfavourable factors during transportation resulting in great losses. The wobbling nature of most of the vehicles coupled with the bad nature of roads causes a lot of mechanical damage to the produce before it reaches its destination. Handlers from developed countries on the other hand use refrigerated containers and trailers which travel on reasonably good roads. Transporting tomatoes in refrigerated trucks is not only convenient, but also effective in preserving the quality of fruits. However, both the initial investment and the operation costs of these vehicles are very high and beyond the affordable reach of most producers in developing countries. Handlers of developing countries therefore transport their produce using the most affordable mode of transport without considering the effect it will have on the postharvest quality of the produce. Even though handlers from developing countries may not have the capacity to use refrigerated trucks, they should be well educated on the consequences that any other transportation option they use may have on their produce.

Postharvest Treatment Techniques for Tomatoes

After harvesting, the tomato fruit still remains living and performs all functions of a living tissue . However, the postharvest quality of the fruit at harvest cannot be enhanced by any postharvest technology but can only be maintained . In order to maintain this quality, there are some postharvest treatment methods that have to be adhered to in order to achieve this goal. Below are some of the treatments methods that can be used for harvested tomatoes.

Refrigeration Storage

Refrigeration is one of the most effective methods of preserving the quality of many fruits and vegetables for several days. Low temperature storage can protect nonappearance quality attributes like texture, nutrition, aroma, and flavour in many harvested fruits . Tomato handlers have also used refrigeration storage for tomatoes in attempt to extend shelf life. However, some fruits and vegetables of tropical origin, like tomatoes, are sensitive to chilling injury when they are stored below their critical temperature of 10°C . This shortcoming of refrigeration storage was reported by Lee et al.  and Babitha et al. where low temperatures from refrigeration storage caused chilling injuries which resulted in pitting, uneven ripening, and fungal infestation of stored fruits. This gives an indication that refrigeration storage may not be the most effective method of storing tomatoes for a long period. Another challenge in using refrigeration storage in tomato handling in most developing countries is the huge initial cost which is beyond the reach of most of underresourced handlers. However, in situations where handlers can afford refrigeration storage and temperature regulation is possible, temperatures of about 10–15°C should be maintained to avoid chilling injuries . In spite of the high cost of refrigeration, it is very important to control storage temperatures and relative humidity during storage, as these two parameters are the main causes of deterioration in fruits and vegetables. The required optimum temperatures of about 10–15°C and 85–95% relative humidity can be achieved by using less expensive methods of cooling such as evaporative cooling system as suggested by Workneh and Woldetsadik . In such cooling system, air temperatures can be decreased to about 16°C, whilst relative humidity can be increased to about 91%, which is appropriate for reducing deterioration of harvested tomatoes due to physiological weight loss . Evaporative coolers can be manufactured locally using low cost materials like jute sacks, wooden planks, and basins.

Postharvest Heat Treatment of Tomatoes

Postharvest heat treatment of fruits and vegetables is receiving more attention as a way of reducing the incidence of chilling injuries in temperature sensitive fruits of tropical origin. It is one of the approaches that can be used to avoid or reduce chilling injuries in stored fruits . Postharvest heat treatments using hot air and heated water have been reported to reduce chilling injuries in fruits like mangoes, oranges, zucchini, and tomatoes . Heat treating of tomato fruit at temperatures of about 37–42°C prior to cold storage can slow down ripening whilst increasing pathogenic resistance when in storage . Some studies have shown that heat treatment prior to storage enhanced or caused no change in some quality traits of stored tomatoes. For instance, TSS of heat treated tomatoes was unaffected when tomatoes ripened at ambient temperatures or when they ripened in a modified atmosphere storage system. However, uniform heat treatment before cold storage at 14°C actually increased TSS and titratable acids (TA) when fruits ripened as compared to the untreated fruits. In situations where refrigeration storage is possible, postharvest heat treatment of tomatoes can be used in conjunction with refrigeration storage in extending shelf life of harvested tomatoes.

Modified Atmosphere Packaging (MAP)

Modified atmosphere packaging (MAP) refers to a packaging technique of using specialised materials in packaging products in a predetermined composition of gases which are mainly oxygen (O2) and carbon dioxide (CO2) after which there is no active effort of modifying the storage space . The packaging materials used in MAP allow for diffusion of gases through them until a stable equilibrium is reached between the external gases and those inside the package . The most commonly used MAP materials are polyethylene terephthalate (PET), low density polyethylene (LDP), high density polyethylene (HDP), polyvinyl chloride (PVC), polypropylene, polystyrene , and some chemically modified derivatives . The benefit of using MAP is not only in providing a modified atmosphere to control ripening , but also in reducing water loss in stored products, reducing mechanical injuries, and enhancing better hygiene which reduces the spread of food-borne diseases. MAP creates water saturated or near-saturated atmosphere (high relative humidity) around the fruit which reduces water loss and shrinkage . Water loss and subsequent shriveling of tomatoes in tropical regions are one of the causes of their deterioration. Fruit shriveling may become evident with any small percentage of moisture loss. The use of MAP by tomatoes handlers in developing countries will therefore prevent or reduce the problem of water loss in harvested tomatoes. However, maintaining excessively high level of relative humidity inside the package can result in moisture condensation on the commodity, which will in turn create conducive environment favourable for pathogenic activities thereby increasing the risk of fruit deterioration . Tomato handlers must therefore be trained in the proper use of MAP for tomatoes to avoid moisture condensation which will result in fruit deterioration.

1-Methylcyclopropene (1-MCP)

The use of 1-methylcyclopropene (1-MCP) has been shown to suppress the action of ethylene in many fruits and vegetables. The rate of ethylene production in harvested climacteric fruit like tomato is indicative of the metabolic activities within the fruit. The higher the metabolic activities within the harvested fruit, the shorter its shelf life. However, the aim of every postharvest technology is to slow down the metabolism in the harvested produce thereby increasing shelf life. The use of 1-MCP by handlers in developing countries is therefore essential in extending shelf life of harvested tomatoes. The use of 1-MCP has been shown to slow down many of the metabolic activities associated with the ripening process such as colour change, cell wall breakdown, and respiration rates making it a useful technique in extending storage life of fruits . Although 1-MCP treatment preserves quality of fruits at advanced ripened stage, its application in green fruit may result in nonuniform ripening. Storing green fruits using 1-MCP must therefore be done with caution in order to achieve full ripeness . In postharvest tomato treatment in particular, 1-MCP has been shown to prolong the shelf life of fruits by retaining fruit firmness and delaying both lycopene accumulation and external colour development. Another benefit of using 1-MCP in tomatoes is the prevention of abscission in fruits that are sold on the vine. This will have a desirable photosynthetic effect in the vegetative tissues which could lead to uninterrupted supply of certain vital substances or nutrients to the fruit thereby increasing the consumption quality. Educating and training handlers on how use 1-MCP in tomatoes will help reduce some amount of postharvest loss associated with the crop.

 Calcium Chloride (CaCl2) Application

Postharvest calcium chloride (CaCl2) application is receiving considerable attention in recent times due to its positive effects on shelf life whilst maintaining quality of many fruits and vegetables . It has been found that calcium chloride delays ripening and senescence, reduces respiration, extends shelf life, maintains firmness, and reduces physiological disorders of many fruits and vegetables . Lester and Grusak also noted that both pre- and postharvest calcium application delayed senescence in many fruits without any negative effect on consumer acceptability. For instance, a 1% CaCl2 treatment was found to have reduced fungal attack, slowed down fruit ripening, and maintained structural integrity of cell walls of strawberry, whilst the same application also delayed softening and increased storage life by almost 3 months in Kiwi fruits stored at 0°C. In loquat fruit, calcium chloride (CaCl2) dip extended shelf life by 4-5 weeks. In tomatoes, calcium chloride treatment is vital for maintaining quality of fruits by reducing the physiological disorders, increasing the fruit firmness, delaying ripening process, and prolonging the shelf life. CaCl2 has been found to have delayed fruit colour development in tomatoes and slowed down ethylene production thereby extending shelf life by 92% . Also, fruits treated with CaCl2 have been shown to have reduced physiological weight loss and maintain higher firmness levels during storage . Bhattarai and Gautam also reported a reduction of physiological weight loss in tomatoes from 19% to 17% by using 0.25% CaCl2 application for 10-day storage. However, CaCl2 is a very cheap and soluble salt which can be dissolved into any concentration for use by producers. The affordable cost of the CaCl2 salt and the relatively easy preparation of the solution and its application therefore make it a favourable choice for adoption by underresourced handlers of developing countries in reducing postharvest losses in tomatoes. A simple and cost-effective way of using CaCl2 is by adding the required dosage of the salt in water used for precooling or cleaning of the fruits after harvesting.

Conclusion

The postharvest quality status and shelf life of the fruits in part will depend on some postharvest handling practices and treatments carried out after harvest. Even though the quality of any fruit after harvest cannot be improved by the use of any postharvest handling practices or treatment methods, it can however be maintained. Shelf life of the fruit can also be extended when appropriate postharvest handling practices and treatment methods are employed. Failure to adhere to these best practices has resulted in high amount of loss especially in developing countries. Although most tomatoes handlers from developing countries may not have high-tech postharvest technologies in addressing postharvest losses in tomatoes, understanding simple and the best postharvest practices has been found to be beneficial. Postharvest handling practices like harvesting, precooling, cleaning or disinfecting, sorting and grading, packaging, storage, and transporting played an important role in maintaining quality and extending shelf life of the tomato fruits after harvest. Also, the use of appropriate postharvest treatment methods like refrigeration, postharvest heat treatment, modified atmosphere packaging (MAP), and 1-methylcyclopropene (1-MCP) and calcium chloride (CaCl2) application was also vital. It is concluded by this study that the quality of the harvested fruit can be maintained and shelf life extended by simply using appropriate postharvest handling practices and treatment methods. Until these simple postharvest practices are followed, postharvest losses in tomatoes will continue to be a major challenge for tomatoes handlers of developing countries.