Mapping of quantitative trait loci controlling low-temperature germinability in rice (Oryza sativa L.)

Abstract

Low-temperature germination is one of the major determinants for stable stand establishment in the direct seeding method in temperate regions, and at high altitudes of tropical regions. Quantitative trait loci (QTLs) controlling low-temperature germinability in rice were identified using 122 backcross inbred lines (BILs) derived from a cross between temperate japonica varieties, Italica Livorno and Hayamasari. The germination rate at 15 degrees C was measured to represent low-temperature germination and used for QTL analysis. The germination rate at 15 degrees C for 7 days of Italica Livorno and Hayamasari was 98.7 and 26.8%, respectively, and that of BILs ranged from 0 to 83.3%. Using restriction fragment length polymorphism (RFLP) and simple sequence repeat (SSR) markers, we constructed a linkage map which corresponded to about 90% of the rice genome. Three putative QTLs associated with low-temperature germination were detected. The most effective QTL, qLTG-3-1 on chromosome 3, accounted for 35.0% of the total phenotypic variation for low-temperature germinability. Two additional QTLs, qLTG-3-2 on chromosome 3 and qLTG-4 on chromosome 4, were detected and accounted for 17.4 and 5.5% of the total phenotypic variation, respectively. The Italica Livorno alleles in all detected QTLs increased the low-temperature germination rate.

Mapping quantitative trait loci controlling low-temperature germinability in rice

“…Further analysis will be required to prove the allelic relationship between these QTLs. Also, the qltg4 QTL detected in this study appears to be the same as those identified in the japonica/indica population (Miura et al, 2001) and japonica/japonica population (Fujino et al, 2004). However, the allelic rela- …”

“…Three QTLs for low-temperature germination have been identified by studies of crosses between temperate japonica Italica Livorno and Hayamasari (Fujino et al, 2004). One QTL, qLTG-3-1 near the marker GBR3001 was located on chromosome 3, and the Italica Livorno allele in this QTL increased low temperature germination (Fujino et al, 2004). Based on the chromosomal location, this QTL appears to correspond to the qltg3 detected in this study.…”

“…The QTL, qltg11 detected in this study shared the similar location as those identified in the 3 previous reports and this result suggests the possibility that these QTLs are allelic. Three QTLs for low-temperature germination have been identified by studies of crosses between temperate japonica Italica Livorno and Hayamasari (Fujino et al, 2004). One QTL, qLTG-3-1 near the marker GBR3001 was located on chromosome 3, and the Italica Livorno allele in this QTL increased low temperature germination (Fujino et al, 2004).…”

“…QTL studies were carried out to identify genes underlying low temperature stress at different developmental stages. These QTL analyses have revealed that lowtemperature germination is controlled by several genes (Suh et al, 1999;Miura et al, 2001;Fujino et al, 2004 ). Three QTLs for low-temperature germination were detected using 98 BC 1 F 1 plants from a cross between Milyang23 and Hapcheonaengmi3 (Suh et al, 1999).…”

“…Three QTLs controlling low-temperature germinability were identified using 122 backcross inbred lines derived from a cross between temperate japonica varieties, 'Italica Livorno' and 'Hayamasari' and a major QTL on chromosome 3, qLTG3-1, explained >30% of the total phenotypic variation in the mapping population and was localized to a 3.7-cM interval on chromosome 3 (Fujino et al, 2004). Subsequently, qLTG3-1 was cloned by a map-based strategy, and it was revealed that qLTG3-1 encodes a novel protein of 184 amino acids with unknown function (Fujino et al, 2008).…”