The Genetic Study On Agronomic Traits、Yield And Qualities Traits Of Oil Sunflower Based On Mixed Linear Model

The research used15inbred lines of the sunflower which had no blood relationship andhad rich genetic background. According to incomplete diallel cross (NC Design II), the64populations were constructed, which included the parental populations, F1populations andF2populations. The genetic models of Additive-Dominance,Additive-Dominance-Maternaland Diploid-Embryo considering Gene-Environment interaction and the method ofmultivariate conditional analysis were employed to evaluate the gene effects andcharacteristics of the main agronomic and quality traits such as yield and oil content. Thepurpose were providing reference for the direct or indirect selection of the target traits andguidance for inbred lines selection and the utilization of the heterosis in oil sunflowerbreeding by Three-Line-Systems. The results were summarized as the followings,1. Six agronomic characters, such as plant height, stem diameter, disc diameter,weight of100grains, kernel percentage, grain weight per disc were mainly controlled bythe additive effect and dominance effect, but the additive effect was more important. Foradditive effect, it was predominant on the grain weight per disc, while it was slightest onkernel percentage. For dominance effect, it was predominant on the kernel percentage,while it was small fertility. The fertility was mainly controlled by the additive effect anddominance×environment effect. Genetic correlation between traits was controlled by theadditive genes.2. The main contribution to yield was from grain weight per disc, plant height andweight of100grains, which exceeded96%respectively. The grain per disc of most hybridshad a high level of contribution value to yield and yield expression was mainly controlledby the dominance effect (heterosis). According to enhancing the yield of hybrid, it wastherefore proposed that the dominance effect of the grain weight per disc could used asprimary selecting index for hybrid yield and plant height and weight of100grains assecondary indexes. As to enhance the yield of hybrid, the dominance effect seems to bemore important than the additive effect.3. The observed seven agronomic characters made different levels of geneticcontribution to oil content of seeds. The great contribution to oil content was made by theadditive net genetic effect of weight of100grains, disc diameter, grain weight per disc andfertile percentage, among them weight of100grains made the maximum with82.32%. As to enhance the oil content of seeds, the additive contribution of agronomic charactersseems to be more important than the non-additive contribution. Among the dominancecontribution, the genetic trends of fertility percentage were favorable. Those weredominant genetic correlation between agronomic characters and oil production per unitarea.4. The accumulation biomass of aboveground dry matter of oil sunflower in differentdevelopmental stages was mainly affected by the dominance alleles. The phases of40～70d and90～100d after seed emerging were budding-flowering and grouting-physiologicalmaturing respectively, among which the dominant effect gene’s expression was steady,continuous and high. In the two phases it was suggested that field management bereinforced and care about the regulation on water and fertilizer. In specific environment,the seedling was easy to be affected by environments at the early stage of seed emergence.Heterosis of aboveground dry matter was mainly of population herterosis over mid-parentswith some of heterobeltiosis. In50d after seed emergence, population heterosis overmid-parents and over better-parents was most obvious phase. From seed emergence to50d,the accumulation biomass of dry matter made the highest contribution to the dominanteffect of yield.5. The oil content of seeds was controlled by both dominance effect and maternaleffect. The additive effect had been detected at peak during the days of20～25d afterflowered, and there were highly significant dominant effects during20～30d afterflowering. It was the predominant stage of heterosis performance, while the maternal effectwas active from35to45days after flowering. The expression of gene effect was easy to beaffected by environment in20d after flowering.6. The oil content(OC), linoleic acid content(LAC) and oleic acid content(OAC) traitswere simultaneously controlled by the genetic effects from embryo genes,cytoplasmicgenes and maternal plant genes.OC and LAC were mainly controlled by cytoplasmic andmaternal genetic effects,while expression of OAC was mainly controlled bycytoplasmic×environment interaction effect.The cytoplasmic heritabilities were larger thanthe embryo and maternal heritabilities for OC and LAC traits,but thecytoplasmic×environment interaction heritabilities were more important than others effectfor OAC.It were more important that the positive cytoplasmic correlations(rC) and maternaldominant correlations(rDm) between the OC and LAC, while OC was negative correlationwith OAC; Moreover,Significant negative correlation were observed between the LAC andOAC, including cytoplasmic effect,maternal additive effect, maternal dominant effect and embryo dominant×environment interaction effect.There were genetic linkage orpleiotropism among cytoplasmic genes of OC and LAC,and including maternal dominantgene. while genetic linkage or pleiotropism were revealed among maternal additive geneand maternal dominant gene for OAC and LAC.