Single Cross Hybrid Maize Seed production:

Isolation Distance

Seed production should be taken in fertile well drained, weed and disease free soil and preferably the fields where preceding crop was not maize to minimize rouging and maintain the genetic purity. At least 400-500 metre distance is required to avoid any contamination.

Male: female ratio

The male: female ratio depends on (a) pollen shedding potential and duration of male parent; (b) male: female synchrony :for better seed setting flowering of female should be earlier than male or male pollen dehiscence should coincide with female silking and (c) season. In general the male: female ratio should be 1:2 or 1:3 or 1:4.

Time of Sowing

To avoid flowering from heavy rains during kharif and low/high temperature during winter season the optimum time of sowing is first week of July during kharif and first week of November during winter.

Method of sowing and layout

It is desirable to plant the crop on ridges. Depending upon the plant type the row and plant spacing should be kept at 60-75 cm and 20 cm, respectively. Identification labels/ tags should be put on the male and female lines to distinguish between them.

Seed Rate

The seed rate depends on size of seed/ test weight, plant type and male: female ratio. 15 kg ha^-1 for female and 10 kg ha^-1 for male is recommended.

Removal of off-type plants and thinning

i) After 12-15 days of sowing: off-type and excess plants should be removed. Proper plant to plant distance should be maintained

ii) At knee high stage all the dissimilar plants should be removed.

iii) At flowering remove dissimilar tassel bearing plant before anthesis from the male.

Detasseling

• Detasseling in female should be done before anthesis.
• It should be practiced row-wise.
• One person should follow to monitor the each row to check that no part of the tassel is left inside.
• The process of detasseling should continue for 8-10 days.
• While detasseling, leaf should not be removed which will reduce the yield. It has been observed that the removal of 1 to 3 leaves along with tassel reduces 5-15 % yield.
• The removed tassel should not be thrown in the field but fed to the cattle as it is nutritive fodder.

Harvesting

If possible male parent should be harvested after pollination. Optimum moisture content in grain at harvesting should be around 20 %. The harvested cobs should spread evenly instead of making heap.

Stages of crop inspection

• At the time of sowing: to monitor the land, isolation distance, planting ratio of male: female, proper sowing time, seed treatment
• During pre-flowering/vegetative stage: to verify the rouging and removal of off type plants

• During flowering stage: to check disease and pest infestation
• During post-flowering and pre-harvest stage: to remove the late and diseased plants
• Differential type of tassel/silk plants
• Harvesting time: to see the proper time of harvesting

Drying and sorting of seed parent cobs

The drying of the cobs should not be done either on the kuccha or pucca flour, rather it should be dried on tarpoline sheets to avoid seed injury and during night the cobs should be kept covered. To maintain the purity, dissimilar, diseased and pest infested cobs should be removed before shelling. The female cobs should be dried up to 13-14 % moisture content before shelling.

Shelling

Shelling of female parent should be done earlier than male to avoid mechanical mixture. Shelling can be done manually or by power operated maize Sheller.

Seed processing:

All under size, broken, damaged etc seeds should be removed for maintaining the quality of seed.

Storage and marketing

Seed drying should be done till the moisture content of the seed is reduced to 8 % and it should be kept in aerated jute bags. Seed should be stored at cool and dry place preferably in cold storage. Poor storage conditions will lead to loss of vigour and poor germination.

Marketing should be done with specifications and standards.