以基因型明确的抽穗期主基因近等基因系EG0~EG7、ER~LR、T65系列为测验系（TLs），在江西南昌（28o 36’ N）夏季自然高温长日（14 h/d）和人工遮光短日（10 h/d），以及海南三亚（18o 14’ N）旱季自然低温短日（11.6 h/d）处理条件下，对籼型杂交水稻恢复系桂99的抽穗期基因及其感温性和基因位点间的互作效应进行了分析。结果表明，桂99在E1、E2和E3位点分别带有感光迟熟等位基因E1、E2和E3，在Se-1位点带有非感光等位基因Se-1e，在Ef-1位点带有早熟基因Ef-1，由此推断其抽穗期基因型为E1E1E2E2E3E3Se-1eSe-1eEf-1Ef-1。迟熟基因E1、E3与早熟基因Ef-1同时存在，E1、E3与Se-1e基因位点间的互作使桂99农艺性状表现弱感光性。感光基因Se-1u（或Se-1n）的存在能增强E位点感光迟熟基因的感光性，感光基因对“TLs×桂99”F2植株抽穗的影响，是延长平均抽穗期，增加迟抽穗植株分布频率。分析了感温性对TLs抽穗期的影响，讨论了以桂99为恢复系配置的杂交水稻组合丰产性和广适性的遗传基础。
Gui99, an indica restorer line of hybrid rice (Oryza sativa L.), has been wildly applied to hybrid rice seed production in the south of China, but the genotype of heading date and gene interaction between photoperiod sensitivity loci and basic vegetative growth period in this restorer line are still unknown, which is definitely restricted to the further use of this restorer line in breeding practice and re-production of hybrid seeds. The objective of this study was to make the genetic analysis of Gui99 in photoperiod sensitivity loci and basic vegetative growth period using heading time nearly isogenic lines EG0–EG7, ER–LR, T65, T65m, T65Eb, T65Ebm. The parents, F1 and F2 generations from the crosses “heading time nearly isogenic lines×Gui99” grown under high temperature, natural long days and short days treated by sunshade in summer-season at Nanchang (28˚36’ N), Jiangxi province, and under low temperature, natural short days in dry-season at Sanya (18°14’ N), Hainan province, where the average day-length is about 14 h/d, 10 h/d and 11.6 h/d during the course of rice growing, respectively, were analyzed in genotype, temperature sensitivity and gene locus interaction. Experimental results showed that Gui99 carried photoperiod sensitivity alleles E1, E2 and E3 in E1, E2 and E3 loci, respectively, a photoperiod insensitive allele Se-1e in Se-1 locus and an earliness allele Ef-1 in Ef-1 locus. The genotype of heading date in Gui99 was E1E1E2E2E3E3Se-1eSe-1eEf-1Ef-1. The weak photoperiod sensitivity in agronomic characters expressed in Gui99 was caused by the coexisting of late heading time genes E1 and E3, earliness gene Ef-1, and gene interaction between E1, E3 with Se-1e. The photoperiod sensitive of late heading time alleles in E loci were enhanced by the photoperiod sensitivity allele Se-1u (or Se-1n). The mean days to heading was delayed and the frequency distribution of late heading plants of F2 population derived from “TLs×Gui99” were increase by the effects of photoperiod sensitivity genes. The genetic foundation of high yield and widely adaptability of hybrid rice combination with this restorer line were also discussed.
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