Genetic Analysis and Mapping of Genes Involved in Fertility of Pingxiang Dominant Genic Male Sterile Rice

Pingxiang-dominant genic male sterile rice （PDGMSR） was the first dominant genic male sterile mutant identified in rice （Oryza sativa L.）, and the corresponding dominant genic male sterile gene was designated as Ms-p. The fertility of PDGMSR can be restored by introduction of a dominant epistatic fertility restoring gene in some rice varieties. In the present study, E823, an indica inbred rice variety, restored the fertility of PDGMSR, and the genetic pattern was found to be consistent with a dominant epistatic model, therefore, the dominant epistatic fertility restorer gene was designated as Rfe. The F2 population from the cross of PDGMSR/E823 was developed to map gene Rfe. The F2 plants with the genotypes Ms-pMs-pRferfe or Ms-pms-pRferfe were used to construct a fertile pool, and the corresponding sterile plants with genotypes Ms-pMs-prferfe or Ms-pms-prferfe were used to con- struct a sterile pool. The fertility restoring gene Rfe was mapped to one side of the microsatellite markers RM311 and RM3152 on rice chromosome 10, with genetic distances of 7.9 cM and 3.6 cM, respectively. The microsatellite markers around the location of the Ms-p gene were used to finely map the Ms-p gene. The findings of this study indicated that the microsatellite markers RM171 and RM6745 flanked the Ms-p gene, and the distances were 0.3 cM and 3.0 cM, respectively. On the basis of the sequence of rice chromosome 10, the physical distance between the two markers is approximately 730 kb. These findings facilitates molecular marker-assisted selection （MAS） of genes Ms-p and Rfe in rice breeding programs, and cloning them in the future.

Genetic relationship of rapeseed yield-related traits revealed by elite lines under multiple environments

To provide a theoretical basis for further improvement of Brassica napus yield, additive dominance with additive - by - additive epistatic effects （ ADAA） genetic model and a 6 X 8 partial dial- lel cross design were used to analyze the genetic effects and correlations of five yield related traits of 14 excellent Brassica napus parental lines and their 46 and F2 populations. The results showed that silique density （SD） , siliques per plant （SPP） , seeds per silique （SPS） and thousand - seed weight （TSW） exhibited not only additive and dominant effects, but also significant epistatic effects. The dominant effects of all five yield - related traits were obviously greater than their additive effects and epistatic effects. Yield per plant （YPP） showed significant genetic correlation with SD, SPP and SPS, and the main component of the genetic correlation was the dominance correlation. SPP and SPS both showed a significant negative correlation with TSW. The SD of rapeseed was genetically correlated with all three components of yield to a certain extent, and there were different components of genetic effects positively correlated with the three yield components, indicating that SD is a potential trait to reconcile the conflict between TSW and SPP as well as SPS.