Mapping and validation of quantitative trait loci for spikelets per panicle and 1,000-grain weight in rice (Oryza sativa L.)

Abstract

This study identified four and five quantitative trait loci (QTLs) for 1,000-grain weight (TGW) and spikelets per panicle (SPP), respectively, using rice recombinant inbred lines. QTLs for the two traits (SPP3a and TGW3a, TGW3b and SPP3b) were simultaneously identified in the two intervals between RM3400 and RM3646 and RM3436 and RM5995 on chromosome 3. To validate QTLs in the interval between RM3436 and RM5995, a BC(3)F(2) population was obtained, in which TGW3b and SPP3b were simultaneously mapped to a 2.6-cM interval between RM15885 and W3D16. TGW3b explained 50.4% of the phenotypic variance with an additive effect of 1.81 g. SPP3b explained 29.1% of the phenotypic variance with an additive effect of 11.89 spikelets. The interval had no effect on grain yield because it increased SPP but decreased TGW and vice versa. Grain shape was strongly associated with TGW and was used for QTL analysis in the BC(3)F(2) population. Grain length, grain width, and grain thickness were also largely controlled by TGW3b. At present, it is not clear whether one pleiotropic QTL or two linked QTLs were located in the interval. However, the conclusion could be made ultimately by isolation of TGW3b. The strategy for TGW3b isolation is discussed.

Comparison of quantitative trait loci for 1,000-grain weight and spikelets per panicle across three connected rice populations

“…The PZM and PMT populations and their planting methods have been described by Xing et al (2002) and Liu et al (2010). The PZT population used in this study consists of 190 F 7 RILs derived from a singleseed descendent of the cross between Zhenshan 97 and Teqing.…”

“…QTL analysis for SPP and TGW was conducted in PZT and for SPP in PZM. The objectives of combining the QTL results of the PZT population with those of SPP and TGW in the PZM and PMT population Liu et al 2010) were to (1) uncover how many QTLs for SPP and TGW could be detected in the three populations, (2) evaluate the relationship of QTL additive effects detected in different populations, and (3) determine the most beneficial alleles from these three varieties.…”

Genetic analysis of yield and yield components in <i>Oryza sativa x</i> <i>Oryza sativa cross</i>

“…Perera et al (1986) suggested that genes with additive, dominant, and epistatic effects controlled both the number of tillers at maturity and the number of panicles per plant. According to Padmaja et al (2008) and Liu et al (2010), there is a predominance of additive gene action for number spikelet per panicle. However, Panwar and Paroda (1983) showed that grain yield is controlled by both additive and dominant gene effects.…”

Genetic and physical mapping of qHY-8, a pleiotropic QTL for heading date and yield-related traits in rice

“…Zhang et al(2006) identified QTLs between RM544 and RM310 on chromosome 8 for heading date, plant height and panicle size co-segregating in trait-performance derived near-isogenic lines of rice. Recently, Liu et al(2009) also identified a QTL for SPP between RM126 and RM483 within the region of chromosome 8. However, due to insufficient molecular markers and small segregation populations, the precise location of the QTLs is still unknown.…”