HYBRID SEED PRODUCTION IN TOMATO

CLIMATE

• Grows best in the warm and dry season• Day temperature 21-25°C• Night temperature of 15-20°C• Temperature ˃ 30°C and ˂ 10°C is not

favorable• Relative humidity 60-70℅

Planting and Spacing

• Seed of male parent should be sown 2-3 weeks earlier to ensure adequate supply of pollen

• Planting ratio 5:1• Spacing – Female line = 80 x 60 cm– Male line = 60 x 40 cm

ISOLATION

• Isolation of male and female parental lines is not necessary

• Seed production field of two hybrids should be isolated by 25 m

Hybridization technique

• Emasculation– 55-65 Days before pollination

Male sterility

• First time used by Prof. C.M Rick 1945• Types– Sporogenous male-sterile mutants– Functional male-sterile mutants– Photoperiod sensitive male-sterile mutant– Temperature dependent male-sterile mutant

Sporogenous male-sterile mutants

• Not determined– Point of arrest in pollen development has not yet

been determined• Premeiotic– Pollen mother cell collapse or abort prior to

meiotic phase• Meiotic – Abnormalities in tapetal cell

Continued…..

• Tetrad– Meiosis completed before pollen abortion. Tapetal

cell fail to expand to normal volume producing small locules at anthesis.

• Microspore – Pollen abortion after microspore formation– Microspores do not enlarge

Functional male-sterile mutants

• Cleistogamous mutant– Petals fails to open

• Dialytic mutant– Growth of epidermal hairs on the anther surface is

prevented.• Exserted stigma mutant– Due to excessive length of style.

Continued……

• Positional sterile mutants– Overlapping or curling of petals– Holds the anthers in close contact with pistil

• Positional sterile-2 mutants– Characterized by the presence of fertile pollen and

indehiscent anthers

Photoperiod sensitive male-sterile mutant

• 100% male sterility in long days (LD 12 h day length)

• Male fertility in short days (SD 8h)

Temperature dependent male-sterile mutant

• Better fruit and seed set at 12°C than 24°C.

Pollination

• 8:00 to 11:00 am• 2 to 3 days after emasculation

Fruit production

• No. of fruits to be kept depend on fruit size of female parent– 30 fruits for large fruited (80 g)– 40 fruits for medium fruited (70-80 g)– 50 or more fruits for small fruited (60 g or below)

Harvesting

• Ripened about 50-60 DAP• Harvested at red ripe stage

Hybrid seed yield

• One kg fruit yields 2.5 to 4 g hybrid seed• Determinate growth 40-50 kg seeds/ha• Indeterminate 70-80 kg/ha