Abstract:

【Objective】In the process of breeding DW-type three-line hybrid rice, cross incompatibility (CI) was found when the cytoplasmic male sterile (CMS) lines were crossed/backcrossed with some varieties. We focused on the traittolayatheoretical basis for improving CI of DW-type CMS lines, so as to promote the application ofDW-type three-line. 【Method】With isocytoplasmallonuclear materials of DW-type and isonuclear alloplasmic male sterile lines of WA-type as female parents, maintainer lines as male parents, cross experimentswere carried out to investigate the cause of CI. Genetic analysis and gene rough mapping were conducted using a set of chromosome single segment substitution lines, which were crossed to a DW-type CMS line DY1A, respectively.【Result】The CI was caused by nuclear-cytoplasmic interactions. Two types of CI were observed that the first type occurred in F₀ crosses and another after backcrossing. For the first type, primarily genetic analysis showed that the CI was controlled by a recessive gene in the nucleus, temporarily named CI_1(t), which was then mapped between the two markers RM6838 and RM5767, linked toRM3395,on chromosome 8.【Conclusion】The CI of DW-type CMS linescould beimprovedby molecular methods.

Key words: DW-type sterile line, cross incompatibility, chromosome single segment substitution lines, genetic analysis, gene mapping

摘要： 目的 在东野型新三系杂交水稻研究过程中,发现不育系与部分品种杂交或回交存在异交不亲和性。对该性状开展研究,为东野型不育系异交不亲和性的改良提供理论依据,促进东野型三系体系的应用。方法 采用东野型同质异核不育系和野败型异质同核不育系分别与保持系品种进行杂交,研究东野型不育系异交不亲和性的产生原因,进而利用一套染色体单片段代换系分别与东野型不育系DY1A杂交,开展遗传分析,并进行基因初步定位。结果 异交不亲和性由核质互作产生,且有两种类型,分别发生在杂交当代和回交世代。针对第一种类型,初步遗传分析显示异交不亲和性在细胞核内受单隐性基因控制,暂命名为CI_1(t),将该基因初步定位在第8染色体RM6838和RM5767两个标记之间,与RM3395连锁。结论 东野型不育系的异交不亲和性可以通过分子手段进行遗传改良。

关键词: 东野型不育系, 异交不亲和性, 染色体单片段代换系, 遗传分析, 基因定位