벼 내랭성 관련 양적형질 유전자좌(QTL) 분석

Analysis of Quantitative Trait Loci Related to Cold Tolerance in Rice

Quantitative trait loci (QTLs) related to cold tolerance traits in rice were identified using 93 SSR markers and 175 recombinant inbred lines (RILs) derived from the intersubspecific cross between the indica cultivar, “Milyang23” and the japonica cultivar, “Stejaree45”. The RILs were grown in cold-water screening plots to evaluate the effects of the cold water treatment on the cold tolerance-related traits of the rice. Normal distribution of traits such as leaf discoloration, heading delay, culm length reduction and number of spikelets was observed in the RILs, with transgressive segregation relative to either parent. On the other hand, the traits spikelet fertility reduction and panicle exsertion were continuously distributed and were relatively skewed towards the traits of the susceptible parent, Milyang23. A linkage map spanning 1,293 cM, with an average interval size of 14.4 cM was constructed using the markers. No significant QTL was detected for leaf discoloration and heading delay. One QTL each for reduction in culm length ratio and spikelet fertility, and number of spikelets were detected. Two QTLs for panicle exsertion were detected on chromosomes 1 and 12, accounting for 5.5 and 5.3% of the phenotypic variance in the trait, respectively. For the 5 QTLs identified in this study, the Stejaree45-derived alleles contributed to desirable agronomic effects. The QTLs for panicle exsertion, reduction in spikelet fertility and spikelet number were on the same location near the SSR marker, OSR20, suggesting the possibility that a single, pleiotropic gene might be controlling these cold tolerance-related phenotypes.