Tropical and subtropical vegetables (2+1)

Preparation of field

• Land should be thoroughly prepared to get fine tilth for seed bed.

Sowing
Seeds soaked in water for 12-24 hours before sowing gives better germination. This is practiced if temperature is very low. If transplanting is to be done, seeds can be sown in PE bags (15x10cm) of 100-200 gauge and germinated under cover to protect them from low temperature. The seedlings are transplanted from the bags at two true leaf stage. Normally the cucurbits do not stand transplantation beyond the stage due to tap root system. The recommended seed rate per hectare is 1.25 kg. Various systems of sowing are followed such as furrow, bed, pit and mounds. In case of furrow sowing the furrows are made at 2.0-3.0 meters with a plant to plant distance of 0.9m with 4-5 seeds in each hill and two vines are finally retained in each hill. Sowing is usually done at top of the sides of furrows and the vines are allowed to trail on the ground.
Pit system is practised especially during rainy season and in river bed cultivation. The pits spaced at 1.5 to 2.0 are dug about a meter deep and well mannered with FYM. 5-6 seeds are sown in a pit and finally 2-3 vines are retained in each pit. In riverbed system of sowing, i.e. in trenches of 30 cm wide, 60 cm deep and of a convenient length is done. The distance between 2 trenches is kept 2-3m. The trenches are filled with FYM, 3-4 seeds are sown in the pits / trenches.

Spacing
The spacing required for sowing depends upon the crop and the variety grown. In general row to row distance of 2.5-3m and hill distance of 60-90 cm is advocated for muskmelon.

Seed treatment
Soaking of seeds in Ethephon at 480 mg/litre for 24 hours improved the germination in muskmelon. At low temperature seed dressing with thiram controlled fungi effectively and also enhanced seed germination.The seeds of muskmelon should be soaked in water overnight and than should be kept in Moist cloth or gunny bag near a warm place before planting. Germination start within 3-4 days.

Training and pruning
Pruning (as the first hermaphrodite flower is borne on secondary branch arising from the eight node, the secondary branches are pinched off up to the seven node) in combinations with staking is found to be more effective. Removing the secondary shoots up to the 7th node on the main stem is found optimal to improve plant growth and fruit set and induce early flowering. The yield and fruit quality is improved with pruning in muskmelon. Fruits from pruned plants have higher TSS, ascorbic acid and reducing sugars and better pulp thickness than un pruned plants.

Nutrition

Well rotten farm yard manure at the rate of 25t/ha is applied to the field at the time of land preparation. Full dose of P&K and ½ of N should be applied as basal dose, remaining of N should be applied at the time of earthing at 4 weeks after sowing. Foliar application of N & K at 1.5% increases the numbers of hermaphrodite flowers. An application of Ca (20-30PPM) and Boron (7.5-10.0 PPM) promotes plant growth, increases fruit yield, flesh and rind thickness.

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Fertilizer recommendations for various states of India

States	N (kg/ha)	P (kg/ha)	K (kg/ha)
Punjab	125	62	62
Haryana	50	25	25
Karnataka	100	75	50
Utter Pradesh	80	75	50
Tamil Nadu	80	60	30
Rajasthan	80	60	40

Irrigation
Usually pits, ridges or beds are lightly irrigated a day or two prior to sowing of seeds and subsequent irrigation is given 4-5 days after seed sowing .In general, irrigation once in 5-6 days will be necessary depending upon soil, temperature and location. It is always necessary to keep moisture well maintained at the root zone to provide rapid tap root development. Irrigation water should not wet the vines or vegetative parts, especially when flowering, fruit set and fruit development is in progress. Usually frequent irrigation is to be reducing when fruits reach maturity and completely stopped at the last stages of harvest. Frequent irrigation is very important in spring summer crop, while in rainy season crop, irrigation may not be necessary at all if rainfall is well distributed between July-September.

Weeding
During early stage of crops, beds, ridges etc. need to be kept free from weeds. At the time of top dressing with nitrogenous fertilizers, weeding and earthing up are done when the vines start spreading; weeding in between the rows or ridges becomes unnecessary since vine growth can smother the weeds. Most of the pre and post emergence weedicides are phytotoxic to the seedlings or reduce plant growth in muskmelon. Application of fluchloralin alone or nitrofen reduce the uptake of N, P & K by weeds in both direct sown and transplanted crops of muskmelon. Some times, nutrient uptake by the crop is enhanced by herbicide application compared to that with no weed control.

Use of Growth regulators
In muskmelon application of ethrel (250ppm) increases the fruiting and in turn the yield. Exogenous application of silver thiosulphate (300-400ppm) induces the male flower in gynoecious muskmelon. These chemicals/plant growth regulators should be applied twice at 2 true leaf stage and second at 4 true leaf stage.NAA at 25 ppm and GA at 10 ppm increases the fruit yield.

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