Synchronous Directive Shuttle Breeding in Maize

摘要

Based on the principles of shuttle breeding and the theories of inheritance of combining ability, a novel method of synchronous directive shuttle breeding (SDSB) was established to overcome the weakness of lacking directionality in conventional maize-breeding program. By using the F2 population of Hybrid 3163 from the U.S. Corn Belt as base population through shuttling between Sichuan and Hainan, China, after repeated testcrossing the individual plants selected from the early S1 and its derived S3 segregating generations, with elite inbred lines 48-2 and 698-3 as testers, followed by multi-location trails and directive selection, two new maize inbred lines, K169 and K236, and three corresponding hybrids, Zhenghong 2, Zhenghong 6 and Zhenghong 115, were developed synchronously within 5～6 years. The hybrids have many merits, including high yields, quality grains, multi-resistance to diseases and lodging, relatively ideal plant types and wider adaptation. The results demonstrate that SDSB is a valuable method to realize the goalof simultaneous breeding for both inbred lines and hybrids, hence increasing breeding efficiency.