Marker Genotypes for Parents of Japonica Hybrid Rice with High Combining Ability of Yield Traits

Scarcity of restorer line with high combining ability is a crucial restraint in the extension of japonica hybrid rice (Oryza sativa L.). This study aimed to screen simple sequence repeat (SSR) marker genotypes that can efficiently reveal high combining ability of hybrid parents. A total of 115 candidate markers were amplified in 6 BT-type cytoplasmic male sterile (CMS) lines and 12 restorer lines. Daily yield per plant (DYP), number of productive panicle per plant (PP), total number of spikelet per panicle (TSP), number of filled spikelet per panicle (FSP), and thousand-grain weight (TGW) were investigated in the 18 parents and 72 F1s derived from the crosses under an NCII design. Twenty marker genotypes were significantly associated with combining abilities (CA) of the parents. Among them, 12 marker genotypes were related to CA for more than one trait simultaneously, and the remaining 8 marker genotypes were only related to CA for one trait. The effect direction of marker genotype on combining ability of multiple traits was either positive or negative. RM152-165/170 was a marker genotype with the largest combining ability of PP and DYP, which increased DYP and PP in F1 by 20.6% and 12.7%, respectively. The marker genotypes with positive effect on increasing yield can be applied directly in the combining ability improvement of japonica rice restorer lines.

摘 要提高杂交粳稻竞争优势的关键是改良其恢复系产量性状的配合力。为使之更富成效, 选用115个SSR引物扩增6个粳稻BT型不育系和12个恢复系的标记基因型, 并按NCII遗传设计配制72个F1组合, 分析18个亲本的单株日产量、单株有效穗数、每穗总粒数、每穗实粒数、千粒重5个性状的配合力, 结合亲本SSR分子标记数据和性状配合力数据筛选了5个性状优异配合力的标记基因型。结果发现20个SSR标记基因型与亲本产量及其构成性状配合力显著相关。其中8个与亲本单个性状配合力相关; 6个同时与亲本2个性状配合力相关; 4个同时与亲本3个性状配合力相关; 2个同时与亲本4个性状配合力相关。同时与多个性状配合力相关的标记基因型, 对各性状的作用方向有正有负。RM152-165/170是单株日产量和单株有效穗数优异配合力效应最大的标记基因型, 可使F1的相应性状值增加20.6%和12.7%。优异配合力的标记基因型可直接用于粳稻恢复系配合力的分子标记辅助改良。