Efficiency of Recurrent Selection for Combining Ability of Yield Trait in Maize Population Yuzong 5

Population improvement is a basis of germplasm enhancement and developing inbred lines in maize (Zea mays L.). For evaluating the combing abilities of Yuzong 5 developed populations derived from 5 cycles of recurrent selection, 30 testcrossing combinations were made using Huangzao 4, Dan 340, Zhongzong 5, Qi 319, Ye 478, and Mo17 as the female parents in 2 locations under the NCII design. The yield per plant of testcrossing combinations was enhanced by 3.57% per cycle, showing a remarkable effect of recurrent selection. Both half-sib recurrent selection (HS-RS) and half-sib reciprocal recurrent selection (HS-RRS) were effective for improving the general combining ability (GCA) of kernel yield and the GCA was improved in each cycle of the populations. After 3 cycles of improvement in Yuzong 5 by HS-RS, the GCA significantly increased from (11.63 of C0 to 5.57 of C3 population (P < 0.01). After 1 cycle of improvement by HS-RRS, the GCA increased from 5.57 of C3 to 9.75 of C4 population. The specific combining ability (SCA) of improved Yuzong 5 × Huangzao 4 was enhanced, which indicated an approaching Reid × SiPT heterotic pattern during Yuzong 5 improvement cycle by cycle.

摘 要根毛是植物吸收水分和养分的重要器官。本研究从T-DNA突变体库中获得一个以中花11为遗传背景的水稻短根毛突变体, 命名为ossrh3 (Oryza sativa short root hair 3) 。该突变体的根毛伸长严重受阻, 并且伴随株高、主根长、侧根长和侧根数目等性状的改变。遗传分析表明该突变性状受1对隐性单基因控制, 利用ossrh3纯合体和籼稻品种Kasalath杂交构建F2定位群体, 利用已公布的水稻SSR (simple sequence repeat) 和自行设计的STS (sequence-tagged site) 标记, 最终将OsSRH3定位在水稻第1染色体上的标记S38978和S39016之间, 物理距离约为37.7 kb, 包含8个候选基因, 为进一步克隆OsSRH3基因和研究禾本科作物根毛发育的分子调控机制提供了依据。