Seed Production of Vegetable, Tuber and Spice Crops

Harvesting

• In general, the crop harvested at harvestable maturity will have the greater seed yield.
  
• In crops the maturation will not be always be uniform but there will be mingling of matured, immatured and over matured based on the time of anthesis and fertilization.
  
• Hence optimum time of harvest for a given seed crop is necessary as beyond the point losses will be greater than the potential seed yield.
  
• Hot dry weather conditions greatly accelerate the rate of natural seed drying on the plant.
  
• Seed moisture can form the most important indication of a crop’s fitness for harvesting.
• Vegetable seed crops are divided in to three groups depending on the state of seed at harvest time.
a. Dry seed

• The seed is usually dried on the plant before harvesting
  
• e.g. okra,brassicas, lettuce, peas, beans, beet and onion.
b. Fleshy fruits

• The ripened fruits are picked from the plants and dried first.
  
• The dried fruits are then opened later to remove the dried seeds.
  
• e.g. chillies, ribbed gourds and bottle gourd.
c. Wet fleshy fruits

• In fruits containing a high level of moisture, the seed has a gelatinous or mucilaginous coating adhering to it.
  
• This has to be removed after seed extraction by a fermentation process or treatment with dilute acids.
  
• Such fruits are harvested when they mature and ripen
  
• e.g. tomato ,brinjal. cucumbers and pumpkins.
Crop	Maturity indices	Remarks
Dried Seeds
Amaranthus	yellowish browning of inflorescence	Prone to shattering
Onion	Seeds become black on ripening in silver colored capsules.10% heads exposed black seeds.	Prone to shattering
Carrot	Second and 3rd order head turn brown	Shattering on delayed harvest
Radish	Pods become brown and parchment like	Do not shatter easily
Turnip	Plants turn to brown parchment colour	Prone to shattering
Coriander	Plants turn to light yellow or brown in colour	Prone to shattering
Peas	Pods become parchment like	Do not shatter easily
Beans	Earliest pods dry & parchment like and remaining have turned yellow	Over maturity leads to shattering and cotyledon cracking
Wet fleshly fruits
Brinjal	Fruit turn to straw yellow colour	Wet seed extraction (fermentation, acid, alkali)
Tomato	Skin colour turn to red and the fruits are softened
Cucumber	Fruit become yellowish brown in colour, and stalk adjacent to the fruit withers for confirming actual seed maturity.	Seed extraction -scooping, (acid, alkali, fermentation))
Watermelon	Tendrils wither on fruit bearing shoot. Skin colour of the fruit resting on the soil is pale yellow and gives dull sound on thumping.
Squash, Pumpkin	Rind becomes hard & its colour changes from green to yellow/ orange or golden yellow to straw colour
True potato seed (TPS)	Berries of potato becomes green to straw coloured and soft
Bitter gourd	Fruit pulp and seed becomes red and light brown respectively	Seeds are separated manually and washed
Fruits dried before extraction
Chillies	Green colour changes to red or yellow	Dry method of seed extraction
Bottle and Sponge gourd	Rind becomes hard and colour changes to light brown or yellow
Vegetatively propagated materials
Colacasia	Drying and dieing of petiole and leaves	Skin becomes tough, uproot
Zinger	Drying and falling down of pseudo-stem turning brown	Select healthy, disease free rhizomes
Turmeric	Drying and falling down of stem turning brown	Select healthy, disease free rhizomes
Garlic	The stem get dry and change in colour from green to brown
Seed potato	Haulms get dry, droop down turn dark brown in colour	Delay leads to spoilage of seed tubes.