Mapping QTLs related to rice seed storability under natural and artificial aging storage conditions

Seed aging or deterioration in rice (Oryza sativa L.) is a major problem for agronomic production and germplasm preservation. Deciphering the genetic mechanism involved in seed aging and improving seed storability is therefore a vital goal for rice breeding. A set of 85 backcross inbred lines derived from the backcross ‘Sasanishiki’ (japonica cv.)/‘Habataki’ (an indica cv. with strong seed storability)//‘Sasanishiki’ was used here to detect quantitative trait locus (QTL) controlling seed storability. Seeds were treated under natural (conventional storage for 48 months) and artificial aging storage conditions (i.e. increased temperature and relative humidity) and germination rate was used to evaluate seed storability. A total of thirteen QTLs for seed storability were identified on chromosomes 1, 2, 3, 4, 5, 7, 11 and 12, respectively. Among them, two QTLs, viz. qSSh-2-1 and qSSh-2-2, were repeatedly detected in both treatment conditions. In contrast, four (qSSh-4, qSSs-5-1, qSSs-5-2 and qSSh-12) and seven QTLs (qSSh-1, qSSh-3-1, qSSh-3-2, qSSh-3-3, qSSh-7-1, qSSh-7-2 and qSSh-11) were detected only once in natural and artificial aging treatments, respectively. The ‘Habataki’-derived alleles were observed to increase seed storability at all the loci except qSSs-5-1 and qSSs-5-2. The existence of QTLs qSSh-1, qSSh-3-1, qSSh-3-2, qSSh-3-3, qSSh-4, qSSh-7-1, qSSh-7-2 and qSSh-11 was confirmed using Habataki chromosome segment substitution lines in a Sasanishiki genetic background. These results provide an opportunity for map-based cloning of major QTLs for seed storability, thereby gaining an understanding of seed storability in rice and possibilities for its improvement.