The Genetic Dissection Of Stay-green And Grain Filling In Rice

The spread abroad of hybrid rice fearfully resolved the lacking of food for the world population, however, most of the widely-used hybrids were early senescence at the development, which leading to poor grain filling and badly reflect the grain quality and yield. There were greater yield potential for intersubspecific hybrids, but the shortcomings such as poor seed setting, later heading date, higher plant height and poor grain filling were widely exited, the discovery of wide-compatibility gene and the accomplishments of recently studies has generally resolved the former three problems, grain filling was regarded as the last barrier for the application of intersubspecific hybrids. So, it was significant for increasing the grain yield to enhance the stay-green ability, postpone the leaf senescence and improve the grain filling.A double haploid (DH) population which was developed from an indica/japonica (Zhenshan 97/Wuyujing 2) crossing and two backcross populations that were derived by backcrossing DHs with their parents were used for this study, the stay-green character was investigated by SPAD value and chlorophyll content two aspects at the heading date (stage I) and 30 days after heading (stage II), the ratios of II/I was denoted the changes between the two stage. After harvesting, the grain filling, yield and other agronomic traits were investigated. The phenotypic mean values for the three populations and the midparental heterosis values for the two backcross populations were used for quantitative trait locus (QTL) mapping and analysis, the genetic basis and correlations betweent the traits were analysed. The main results were as follows:1. There are 54 QTLs were detected in the three population for the SPAD value of the flag leaf and the second leaf, distributed on 17 chromosome intervals of 9 chromosomes except for chromosome 5, 9 and 10. A mass of QTLs were detected at the intervals of chromosome 3, 6 and 8, indicated these intervals were important to the genetic basis in SPAD value. There were 39 additive loci and 15 over-dominant loci of 54 QTLs, alleles from Wuyujing 2 at 24 of 39 additive loci had positive effects, at 7 of 15 over-dominant loci, the heterozygotes had positive effects.2. 59 QTLs were detected in the three population for the chlorophyll a, b content of the flag leaf, distributed on 21 chromosome intervals of 10 chromosomes except for chromosome 5 and 11. The intervals of chromosome 3, 7 and 8 were important to the genetic basis in chlorophyll content. Alleles from Wuyujing 2 at 14 of 36 additive...