Quantitative trait loci associated with seed set under high temperature stress at the flowering stage in rice (Oryza sativa L.)

Abstract

High temperature stress (HTS), an increasingly important problem in rice production, significantly reduces rice yield by reducing seed set percentage (SSP). Breeding rice varieties with tolerance to HTS at the flowering stage is therefore essential for maintaining rice production as the climate continues to warm. In this study, two quantitative trait loci (QTL) underlying tolerance to HTS were identified using the recombinant inbred lines (RILs) derived from a cross between the HTS-tolerant rice cultivar 996 and the sensitive cultivar 4628. SSP was used as the heattolerance indicator for the lines, which were subjected to HTS at the flowering stage in both field and growth chamber experiments. Two major QTL that affected SSP in both conditions were detected in the interval between RM5687 and RM471 on chromosome 4, and between RM6132 and RM6100 on chromosome 10. The QTL located on chromosome 4 explained 21.3% in field and 25.8% in growth chamber of the total phenotypic variation in SSP, and increased the SSP of plants subjected to HTS by 9.1% in field and by 9.3% in growth chamber. The second QTL located on chromosome 10 explained 11.5% in field and 11.6% in growth chamber of the total phenotypic variation in SSP, and increased the SSP of plants subjected to HTS by 7.2% in field and 7.0% in growth chamber. The positive additive effects of the two QTL were derived from the 996 alleles. The two major QTL identified in this study could be useful for further fine mapping and cloning of these genes and for molecular marker-aided breeding of heat-tolerant rice cultivars.

Field level evaluation of rice introgression lines for heat tolerance and validation of markers linked to spikelet fertility

“…Several QTLs have been mapped for heat tolerance at flowering stage (Ye et al 2011;Jagadish et al 2010a;Zhang et al 2008;Xiao et al 2011). In our study, RM250 and RM88 were associated with days to flowering in normal and poly cover house methods respectively but same type of alleles were observed in both susceptible and tolerant checks indicating they are not specific to a haplotype.…”

“…Marri et al (2005) reported RM263 and RM183 on chromosome 2 linked to yield enhancing QTLs qyld 2.1 and qyld 2.2 and RM297 and RM223 to high spikelet number per panicle. Xiao et al (2011) reported two QTLs qPF4 and qPF6 between RM5687 and RM471 on chromosome 4 and between RM190 and RM225 on chromosome 6 respectively, affecting pollen fertility in RILs derived from a cross between a heat tolerant rice cultivar 996 and a sensitive cultivar 4628. However these markers were not associated with any trait in our study.…”

“…Genetic variation in the ability of rice to maintain spikelet fertility and seed set under heat stress allows selection of genotypes with increased tolerance to heat stress. QTL mapping and gene expression studies for heat tolerance have been carried out in rice at different stages such as booting, flowering and grain filling stage (Bui et al 2014;Wei et al 2013;Liao et al 2014;Poli et al 2013;Xue et al 2012;Xiao et al 2011;Ye et al 2011;Jagadish et al 2010a;Zhang et al 2008;Chen et al 2008;Zhao et al 2006). QTLs for heat tolerance were mapped on all chromosomes except chromosome 7 but fine mapping of these QTLs has not been reported.…”

Breeding efforts to mitigate damage by heat stress to spikelet sterility and grain quality

“…Some of the QTLs identified in different populations are overlapped or closely linked (Table 1). Among the identified QTLs, a QTL for spikelet fertility under high temperature, qHTSF4.1 from n22, was identified in different genetic backgrounds in different studies (Jagadish et al, 2010;Xiao et al, 2011;Ye et al, 2012Ye et al, , 2015a. To fine map and validate the effect of heat tolerance QTL qHTSF4.1, PCR-based SnP markers were developed and used to genotype BC 2 F 2 , BC 3 F 2 , BC 3 F 3 , and BC 5 F 2 populations from the cross combination of IR64/n22.…”

Karakter Seleksi pada Generasi Awal untuk Adaptasi Padi terhadap Cekaman Suhu Tinggi

“…Cekaman suhu tinggi selama fase berbunga padi menyebabkan penurunan vigor serbuk sari, dan fertilitas spikelet (Prasad et al, 2006;Jagadish et al, 2011;Poli et al, 2013). Penurunan vigor serbuk sari dapat dianggap sebagai faktor fisiologi yang bertanggung jawab terhadap penurunan produksi gabah pada kondisi suhu tinggi (Tang et al, 2008;Zhang et al, 2008;Xiao et al, 2011).…”