Breeding and Application of Inbred Lines YA3237 and YA3729

Combination Yu32×S37 and S37×N29 were crossed by excellent tropical inbred S37 and temperate Yu32 and N29,which were treated by mixed pollination in S1 and successive self-cross in S2 and subsequent generations.The offsprings were tested and identified at the same time.Through inbred lines YA3237 and YA3729 which centralized the excellence of temperate and tropical germplasm,also called were selected.According to the heterosis model of temperate-tropical inbred line×temperate line and temperate-tropical inbred line×tropical line,acted as parent,15 new maize hybrids were selected,examined and approved.These varieties were popularized in the south and north of China and the total area have reached 909 000 ha.