Grain yield responses to moisture regimes in a rice population: association among traits and genetic markers

Abstract

Drought is a major constraint to rice (Oryza sativa L.) production in rainfed and poorly irrigated environments. Identifying genomic regions influencing the response of yield and its components to water deficits will aid our understanding of the genetic mechanism of drought tolerance (DT) of rice and the development of DT varieties. Grain yield (GY) and its components of a recombinant inbred population developed from a lowland rice and an upland rice were investigated under different water levels in 2003 and 2004 in a rainout DT screening facility. Correlation and path analysis indicated that spikelet fertility (SF) was particularly important for grain yield with direct effect (P=0.60) under drought stress, while spikelet number per panicle (SN) contributed the most to grain yield (P=0.41) under well-watered condition. A total of 32 quantitative trait loci (QTLs) for grain yield and its components were identified. The phenotypic variation explained by individual QTLs varied from 1.29% to 14.76%. Several main effect QTLs affecting SF, 1,000-grain weight (TGW), panicle number (PN), and SN were mapped to the same regions on chromosome 4 and 8. These QTLs were detected consistently across 2 years and under both water levels in this study. Several digenic interactions among yield components were also detected. The identification of genomic regions associated with GY and its components under stress will be useful to improve drought tolerance of rice by marker-aided approaches.

Mapping of QTLs for Grain Yield and its Component Traits under Drought Stress in Elite Rice Variety of Assam

“…In the present study significant correlation was observed among the traits i.e., panicle length, number of chaff per panicle and spikelet fertility resulting in clustering of their QTLs on chromosome 6 in the same marker interval of RM253-RM30. Clustering of QTLs were also reported earlier in rice Zou et al, 2005) indicating tight linkage of different polygenes could be the possible reasons for the congruence of several QTLs. Another reason for the coincidence of QTLs is that character correlation may be attributed to the effect of pleiotropy or even very close linkage of genes (Lin et al, 1996).…”

NAL1 allele from a rice landrace greatly increases yield in modern indica cultivars

“…In this region, where SPIKE was identified, several QTLs for TSN have been detected, among which the alleles from japonica or tropical japonica cultivars increased TSN (30)(31)(32)(33)(34)(35)(36)(37)(38). Hitherto, no gene for TSN or grain yield in this cluster has been isolated (39).…”

Genetic, proteomic and metabolic analysis of the regulation of energy storage in rice seedlings in response to drought

“…As mentioned above, we detected drought-tolerant quantitative trait loci (QTL) in an RIL population from a cross of the Zhenshan97 and IRAT109 rice strains [86,87]. It was found that positive alleles for the majority of loci came from IRAT109.…”

“…These stains are also used in several countries as a high-yielding and drought-resistant cultivar. IRAT109 is widely used as parental line in rice breeding programs and in the development of diverse genetic populations, such as the recombinant inbred line (RIL) or backcross inbred line (BIL) from crosses of Zhenshan97/IRAT109, IRAT109/Yuefu, and Akihikari/IRAT109 [86][87][88][89]. In our group, a comprehensive research platform was set up to conduct long-term research on rice drought resistance.…”

“…Pyrroline-5-carboxylate dehydrogenase RM134-RM420 qSF-7b Os07g0675000 Acyl CoA dehydrogenase RM434-RM257 QLds9 Os09g0465600 Phosphohexoisomerase Os09g0449600 Aconitase Os09g0465600 Phosphohexoisomerase MRG5454-RM235 QRfp12, qTGW-12b Os12g0502400 Phosphoserine phosphatase a) QTLs named with a ''Q'' were reported by Yue et al [86], and those with a ''q'' were reported by Zou et al [87]. Both studies were conducted using the same RIL population derived from a cross between the Zhenshan97 and IRAT109 strains.…”