QTL analysis of drought tolerance traits in rice during the vegetative growth period

Abstract

Drought affects the growth and development of rice from direct seeding or transplanting to maturity in northern China. It is important to carry out QTL mapping for drought tolerance to improve rice breeding. In this study, a rice RIL population consisting of 253 families was constructed by crossing Miyang 23 with Jileng 1. The leaf rolling index (LRI), leaf withering degree (LWD) and leaf chlorophyll content (LCC) were measured over three years, and QTLs for these traits were mapped. The results showed that LRI, LWD and LCC were all quantitative traits controlled by multiple genes. A total of 28 QTLs related to three drought-resistant indices were detected; four QTLs controlling LRI and LWD were detected on Chromosome 1. qLRI1-1 and qLWD1-4 were located in the interval of AH01001843-RM302, explaining 10.30% and 4.90% of the phenotypic variation, respectively; qLWD1-2B and qLRI-1JC were both located in RM315-S01167A, and qLWD1-2B was explained 11.15% of the phenotypic variation, while qLRI-1JC explained 7.96% of the phenotypic variation. The two QTLs located on Chromosome 5, qLWD5-1B and qLRI5, were located in CMB0526.3486-RM87. qLWD5-1B explained 6.93% of the phenotypic variation, while qLRI5 explained 8.79%-9.13% of the phenotypic variation. The two QTLs detected on Chromosome 12, qLWD12 and qLRI12, were located in the S12099-CMB1226.0 interval and explained 4.59%-7.25% of the phenotypic variation. The above QTLs, including qLWD1-2B, qLRI1-1JC, qLWD5-1B and qLRI5, have been detected many times. Future work should involve implementing in-depth fine mapping of these QTLs and using the identified markers in the drought resistance molecular marker selection breeding of rice.