QTL analysis for resistance to preharvest sprouting in rice (Oryza sativa)

Abstract

Preharvest sprouting (PHS) is caused by early breaking of seed dormancy. In Sichuan, a major hybrid rice seed production area of China, PHS in hybrid seeds originated from ÔG46AÕ parent may lead to severe yield loss, causing serious damage to agricultural production. To detect quantitative trait loci (QTLs) governing PHS, we developed an F 2 population of 164 plants derived from ÔG46BÕ and ÔK81Õ, a nearisogenic introgression line of G46B, with high level of resistance to PHS. PHS was evaluated under controlled field and laboratory conditions. Using simple sequence repeat markers, we constructed a linkage map from this population and identified three QTLs for PHS, namely qPSR2, qPSR5 and qPSR8, which were located on chromosomes 2, 5 and 8, respectively. Among these QTLs, qPSR8, residing in the interval between RM447 and RM3754 on chromosome 8, was the major QTL controlling PHS, for it had a relative high logarithm of the odds (LOD) score and explained 43.04% of the phenotypic variation. These results were correspondent to those identified in extreme low germination rate plants (ELGP) using linkage and linkage disequilibrium. At all loci, ÔK81Õ was responsible for enhancing the resistance to PHS.

Quantitative trait loci for seed dormancy in rice

“…The QTL qDGE1 on chromosome 1 and qDGR5b on chromosome 5 in this study have not been detected in earlier studies, but there are three homologues of DOG1 in the QTL regions, which could be some new QTLs. It is a little surprising that no PHS QTL was detected in our SD QTL regions (Gao et al 2008;Hori et al 2010). In addition, all the three homologues of DOG1 (with low P values, P B 3.8e-06) are members of the transcription factor HBP-1b, which is reported to contain a bZIP domain at the N terminus (Mikami et al 1994).…”

“…Several genes or chromosomal regions affecting SD have been mapped successfully in barley (Oberthur et al 1995;Larson et al 1996), wheat (Anderson et al 1993;Flintham et al 2002;Roy et al 1999), cultivated rice (Dong et al 2003;Guo et al 2004;Gu et al 2004) and wild rice (Cai and Morishima 2000;Thomson et al 2003;Lee et al 2005;Li et al 2006;Gu et al 2005). Meanwhile, several QTLs for PHS in rice were identified in progeny of intersubspecies crosses (Gao et al 2008;Hori et al 2010). Dozens of QTLs associated with rice SD or PHS have been reported, which indicates that different accessions vary in their genetic loci controlling SD or PHS.…”

The qSD12 underlying gene promotes abscisic acid accumulation in early developing seeds to induce primary dormancy in rice

“…The relatively constant phenotypic effect makes the dormancy allele ideal for use to improve resistance to pre-harvest sprouting. Pre-harvest sprouting is a problem in some rice production areas, and for some types of rice such as male sterility lines of hybrids (Gao et al 2008(Gao et al , 2009). The selected isogenic line IL SD12 DD contains only a chromosomal segment of about 200 kb from weedy rice, on which there are 9 polymorphic markers (Fig.…”

Genome-wide QTL analysis for pre-harvest sprouting tolerance in bread wheat

“…Subsequent studies involving quantitative trait loci (QTL) analysis using diverse mapping populations identified a number of genes/QTL involving all the 21 different chromosomes (Anderson et al1993;Bailey et al 1999;Roy et al 1999;Zanetti et al 2000;Kato et al 2001;Mares and Mrva 2001;Groos et al 2002;Flintham et al 2002;Kulwal et al 2004Kulwal et al , 2005Mori et al 2005;Mares et al 2005;Ogbonnaya et al 2006Ogbonnaya et al , 2008Imtiaz et al 2008;Chen et al 2008). In rice and barley also, QTL for PHS/ dormancy were identified on all the chromosomes in each case (Gao et al 2008;Ullrich et al 2008). Thus, the genetics of PHS in cereals is complex, which makes the development of PHS tolerant cereals a major challenge for crop geneticists and plant breeders.…”