Abstract:

The recessive red hull rice is an ideal genetic tool for hybrid rice seed production. In order to breed new hybrid combinations with high yield and quality which are suitable for mixed seeding, we explored the yield factors on mixed seeding ‘Longke638S’ and the Red-hull line ‘Xianhui XK01’.‘Longke638S’ was used as female parent and red-hull line ‘XianhuiXK01’ as the male parent, based on the orthogonal design method, we designed three factors: the treatment of male parent (throw-planting or unaccelerating germination before sowing), seeding method (mechanized or artificial mixed seeding), parental lines ratio (fixed female/male seed ratio of 6: 1, 9:1, 12:1, 15:1). The plots yield was measured when the seed parents were ripe. The plant laboratory test was conducted by randomly sampling five individual plants in each plot. SPSS and other software were used for data analysis. The results showed that parental lines ratio was the main factor affecting seed yield on the mixed seeding of ‘Longke638S’ and ‘XianhuiXK01’. The optimal parameter was mechanized mixed seeding, parental lines ratio (6:1), and pollen parent seed treated by throw-planting. In this case, the seed production yield was the highest, up to 4157.85 kg/hm², and the outcrossing rate was 66.8%. In conclusion, the parental lines flowering at the same time and the seed parent has high yield and outcrossing rate, and basically conforms to the requirements of mechanized seed production. This experiment provides data for the seed production of mechanized mixed seeding in the future.

Key words: hybrid rice, red-hull line, mixed seeding, orthogonal design, parental lines ratio, mechanized seed production