Identification of Marker Genotypes Associated with Elite Combining Ability for Quality Traits in Parents of Hybrid <I>Japonica</I> Rice (<I>Oryza sativa</I> L.)

Abstract

The area planting japonica hybrid rice is only 3% of the total area (8.28×10 6 ha) of japonica rice. One of the reasons why japonica hybrid rice popularized slowly is that grain quality of hybrid was inferior to that of conventional cultivars. In order to improve grain quality combining ability of parental lines more efficiently, SSR marker genotypes of elite combining ability for 10 quality traits, namely, brown rice rate (BRR), milled rice rate (MRR), head rice rate (HRR), grain length (GL), grain width 406 作 物 学 报 第 37 卷 (GW), percentage of chalky grain (PCG), chalkiness degree (CD), gelatinization temperature (GT), gel consistency (GC), and amylose contents (AC), were identified in this study, by analyzing the data of combining ability and SSR markers in six CMS lines and twelve restorer lines, which were genotyped using 115 pairs of SSR primers. A total of 30 SSR marker genotypes were significantly associated with combining ability of the 10 quality traits. Twenty-five of them were marker genotypes for unfavorable combining ability of quality traits. The remaining five marker genotypes were associated with elite combining ability for quality traits of parents. RM263-175/180 and RM444-230/240 were marker genotypes of elite combining ability for HRR, which increased 3.2% and 2.5% of HRR in F 1 , respectively. RM3-120/150 shortened GL value in F 1 by 2.4%. RM444-180/240 increased GW trait value of F 1 by 2.1%. RM428-273/294 decreased AC trait value of hybrid rice harvested from F 1 plants by 7.0%. Among the SSR marker genotypes associated with combining ability of the 10 quality traits, eight marker genotypes also affected combining ability of yield components simultaneously. RM3-120/150 increased simultaneously total spikelets per plant (TSP) and filled spikelets per plant (FSP) in F 1 by 15.9% and 10.9%, respectively. RM1211-150/160 decreased trait values of BRR and MRR in F 1 by 0.9% and 1.1%, respectively, and simultaneously increased trait values of TSP and FSP in F 1 by 21.8% and 20.4%. RM23-150/160 increased trait values of PCG and CD in F 1 by 44.1% and 45.7%, and simultaneously increased daily yield per plant and TSP in F 1 by 11.2% and 11.6%, respectively. These results could be used for directing improvement of combining ability of parents for quality traits and yield traits through the marker-assisted selection, and for determining parents for making combinations of hybrid japonica rice in the future.

QTL Analysis for Seven Quality Traits of RIL Population in Japonica Rice Based on Three Genetic Statistical Models

“…Moderate amylose content was preferred in rice (Huang et al, 2011). QTL qAC9.1 detected by MIMR, with the contribution rate of 29.85% and the additive effect of -4.63%, was located closely to the marker RM410 (Table 2).…”