QTL Analysis For Main Agronomic Traits Of Rice（Oryza Sativa L.） By F₂Derived From Double-Dwarf02428DD And Nanjing11

Using F2populations derived from02428DD/Nanjing11as mapping populations, We constructed a genetic linkage map, positioned QTLs about main agronomic traits of rice and estimated their genetic effects. The research was both of theoretical significance and practical significance for exploring important QTLs of rice and molecular breeding. The main results are as following:1. One hundred eighty-nine lines of F2were analyzed by ninty-five SSR markers to constructed a genetic linkage map, which covered a total of1110.6cM on twelve chromosomes (forteen linkage group) with an average interval of11.7cM between adjacent loci. And the markers distributed on chromosomes equably.2. A total of fifteen QTLs for the ten traits were detected in nine regions on seven chromosomes. Among the QTLs, there were two QTLs for panicle number, one QTL for spikelet number per panicle, two QTLs for grain weight, one QTL for seed setting rate, one QTL for panicle length, one QTL for primary branch number, two QTLs for secondary branch number, one QTL for flag leaf length, two QTLs for flag leaf length to width ratio, two QTLs for basal culm thickness, respectively.3. For panicle number, qPN10and qPN2were detected, with the explained phenotypic variances of16.65%and6.55%respectively. Their positive alleles were both from Nanjing11, the male parent. For spikelet number per panicle, one QTL was detected, qSP8, which totaly explained14.76%of phenotype variance. Its positive allele was also from the male parent Nanjing11. For1000-grain weight, two QTLs were located, qGW6and qGW7, Whose explained phenotypic variances were6.86%and6.52%respectively, its positive allele of qGW6was from the male parent, Nanjing11and that of qGW7was from the female one,02428DD. For seed setting rate, one QTL was identified, qSF10, which explained10.18%of the phenotypic variation for the trait. Its positive allele was from Nanjing11. For panicle length, one QTL, qPL5, was discovered. which explained9.04%of phenotypic variance. Its positive allele was from02428DD. For primary branch number and secondary branch number, there were two and one QTLs were detected respectively. qPBN8-2and qPBN8-1controlling primary branch number, were both located on chromosome8aparting from each other28cM. They totally explained9.17%and6.35%of the phenotypic variances (both less than10%). Their positive alleles were both from Nanjing11. qSBN8, controlling secondary branch number, was also located on chromosome8aparting from qPBN8-2only6cM. It was a major QTL as Its explained phenotypic variance was13.06%. And its positive allele was from Nanjing11. qFL12for flag leaf length was located on chromosome12, which totaly explained13.70%of phenotype variance. Its positive allele was from the female parent02428DD. Two QTLs, qFLWR10and qFLWR8, for flag leaf length to width ratio, explained11.49%and7.20%of phenotype variance respectively. Their positive alleles were from Nanjing11and02428DD, respectively. Two QTLs, qBCTS and qBCT7, controlling basal culm thickness were detected, with the explained phenotypic variances of13.99%and8.48%respectively. Their positive alleles were both from the female parent02428DD.4. The linkage relation among some QTLs can partially explain the correlation between the phenotypic values of some traits. In majority of cases, positive QTLs or negative QTLs were linked with each other, whereas it was few when positive QTL(s) were linked with negative one(s). The result of which may provide convenience for breaking up the unfavourable linkages. All QTLs in our study, whose gene action were over dominance or partional dominance, may be ultilized in heterosis.