Genetic And QTL Analysis Of Alkaline Tolerance In Rice

The quantitative trait loci (QTLs) for alkaline tolerance such as germination capacity at germination period; root number, root length and seedling height at early seedling stage; dead leaf percent at seedling stage; main culm length, panicle exsertion, panicle number, spikelets per panicle, imperfect grain number, seed setting rate, 1000-grain weight, main culm panicle length, grain yield per plant at all developmental period in rice under alkaline stress condition and natural condition was identified by using a F2.3 population including 200 lines derived from a cross between two japonica cultivars "Gaochan106/Changbai 9". The results were as follows.1. All agronomic traits investigated in germination period, early seedling stage, seedling stage and all developmental period in rice were showed a continuous distribution near normal, as well as the relative alkali damage rate of germination capacity, root number root length and seedling height were displayed a continuous distribution near normal in F₃ family lines, which indicated that these traits were quantitative traits and were controlled by many genes.2. Germination capacity at germination period were positively correlated with root number and root length and seedling height at early seedling stage; panicle exsertion were positively associated with main culm panicle length, panicle number, 1000-grain weight and grain yield per plant under alkaline condition.3. A molecular linkage map of 74 SSR markers was constructed by using interval mapping, and covered a total length of 1246.2 cM with an average distance of 16.84 cM between adjacent markers in rice genome.4. QTLs detected related to alkaline tolerance were as follows:4.1 7 QTLs correlated with germination capacity at the germination period were identified on chromosome 5, 6, 9, 10, 11 and 12; 6 QTLs associated with relative alkaline damage rate of germination capacity were identified on chromosome 2, 6, 7 ,9 , 12 under alkaline stress.