杂交水稻组合抽穗期的遗传分析

Genetics of Combination Rice Hybrids at Heading Stage

【目的】水稻的抽穗期是一个复杂的遗传性状,其决定了水稻品种适应的生态区域,了解抽穗期的遗传基础,对水稻高产育种具有重要意义。【方法】以华占为研究材料,构建天优华占、恒丰优华占、五丰优华占3个杂交组合的P1、P2、F1、F2、BC1-1、BC1-2等6个遗传世代群体。运用植物数量性状主基因+多基因混合模型分析生育特性的遗传效应。【结果】3个杂交组合抽穗期的最适遗传模型均为MX1-AD-ADI。F2群体的主基因遗传率分别为10.13%、12.64%、13.65%,多基因遗传率分别为88.45%、85.94%、83.66%;BC1-1群体的主基因遗传率变幅为15.16%~23.66%,多基因遗传率变幅为65.33%~69.75%,抽穗期遗传模式与F2群体相似,主要受多基因控制;而以保持系为轮回亲本的3个回交群体BC1-2的抽穗期则受主基因和多基因共同影响,主基因遗传率变幅为42.03%~47.78%,多基因遗传率变幅为45.17%~50.77%。【结论】抽穗期受多基因控制,遗传基础复杂。在育种中的抽穗期选择上,应根据不同群体的遗传特性进行生育期的选择。

【Objective】 The very complex genetic characteristics at heading stage that dictate the adaptability of a rice variety to ecological zones were studied. 【Method】 Using Huazhan as male parent, populations of 6 generations(i.e., P1, P2,F1, F2, BC1-1, and BC1-2) of combination rice hybrids, Tianyou Huazhan(TH), Hengfengyou Huazhan(HH), and Wufengyou Huazhan(WH), were constructed. Genetic analysis on the heredity of plant height was performed using the "main gene+polygene hybrid genetic model" on the populations. 【Result】 MX1-AD-ADI was found to be the best fit genetic model for the heading of all 3 hybrids. On F2, the main genetic heritability of TH was 10.13%, that of HH 12.64%, and that of WH13.65%;and, the polygenic heritability of TH was 88.45%, that of HH 85.94%, and that of WH 83.66%. For the BC1-1 population, the main gene heritability ranged from 15.16% to 23.66%, and the polygene from 65.33% to 69.75%. For the two populations, the genetic patterns at the heading stage were mainly controlled by the polygenes. But the heading of the 3 backcrossing BC1-2 populations with the maintainer as recurrent parent were affected by both the main genes and polygenes with the former exerting a heritability between 42.03% and 47.78 %, and the latter between 45.17% and 50.77%.【Conclusion】 Rice heading was highly complicatedly controlled by multiple genes. In breeding, selection of heading period would, therefore, require a thorough analysis beforehand on the genetic characteristics of the specific target population.