Analysis Of Genetic Potential Of Strong Dominant Combinations In Hybrid Rice

Rice is one of the important food crops.Effective use of heterosis is the key technical means to cultivate high-yield varieties.In order to reveal the dominant potential and genetic background of the strong dominant hybrid rice combination.In this study,11 rice strong dominant hybrid combinations were selected as the tested materials,namely Teyou009,Qianyou 3301,Yiyou 673,Taiyou 3301,Hengfengyou Huazhan,Tianyou 3301,Guang 8 You 165,Quanyou Simiao,Luyou Mingzhan,Tianyou Huazhan,II You Ming 86.Three generations of genetic groups such as F₁,F₂ and F₃ were constructed.The yield trait?grain weight per plant?and several yield-related traits(number of effective panicles per plant,length of the main panicle,grain length,grain width.Statistical methods were used to analyze the mid-parental value,the mid-parental advantage and the super-parental advantage among generations,and the genetic parameters such as additive variance,dominant variance and heritability were estimated.The genetic basis of the above traits of the four generations?P1,P2,F1,F2?of the seven hybrid combinations containing the parents was analyzed using the main gene+polygenic mixed genetic model of plant quantitative traits.The research results provide a theoretical reference for the effective utilization of heterosis and the improvement of breeding efficiency of high-yield varieties.The main results are as follows:1.Results of polygenic additive-dominance model:Compared with the parents,the traits of the F₁ generation have obvious mid-parent advantages,super-parental advantages and competitive advantages,and the F₂ generation and the F₃ generation are successively degraded.The generalized heritability of 11 combinations of individual plant weights ranged from 36.72%to 87.40%and the narrow heritability ranged from 27.21%to 61.44%.The generalized heritability of effective panicles number ranged from 25.79%to 64.58%,and the narrow heritability ranged from 28.88%to 47.09%.The generalized heritability of the main panicle length ranged from 69.24%to 94.10%,and the narrow heritability ranged from 45.67%to 77.89%.The generalized heritability of grain length increased by 82.43%-98.13%,and the narrow heritability rate ranged from 51.11%to 84.17%.The generalized heritability of grain width was 73.06%-97.00%,and the narrow heritability was 50.11%-82.83%.In breeding,the directional selection of each generation should be carried out according to the genetic rate of different traits.2.Genetic analysis of seven F₂ generation traits with two parents was carried out by using the plant main gene+polygenic mixed genetic model.The specific results are as follows:The inheritance of grain weight per plant:There were four genetic models for grain weight per plant.Three of the combinations were in accorded with“two major genes with additive effects+polygenic with additive-dominant effects model”?Hengfengyou Huazhan,Tianyou Huazhan and II You Ming 86?,in which the heritability of major genes varied 65.92%-74.71%,while the polygenic heritability varied 6.33%-13.76%.Two combinations were in line with“two major genes with complete dominant effects+polygenic with additive-dominant effects models”?Guang 8 You 165 and Luyou Mingzhan?,in which the heritability of major genes was 65.18%and69.25%,and the polygenic heritability was 16.60%and 20.30%respectively.One combination was in line with“two major genes with average-additive-dominant effects+polygenic additive-dominant effects model”?Quanyou Simiao?,in which the heritability of major genes was51.09%,while the polygenic heritability was 20.31%.One combination was consistent with“two major genes with additive-dominant-epistasis effects+polygenic with additive-dominant effects model”?Tianyou3301?,in which the heritability of major genes was 63.74%,and the polygenic heritability was 12.12%.The inheritance of effective panicles number:There are mainly two genetic models.Three of the combinations were consistent with the“two major genes with additive-dominant effects+polygenic with additive-dominant effects model”?Tianyou 3301,Quanyou Simiao,II You Ming 86?,in which the heritability of major genes varied 41.73%-53.05%,while the polygenic heritability varied6.95%-18.31%.Four combination accorded with“two major genes with complete dominant effects+polygenic with additive-dominant effects model”?Hengfengyou Huazhan,Guang 8 You 165,Luyou Mingzhan,Tianyou Huazhan?,in which the heritability of major genes varied48.58%-61.10,while the polygenic heritability varied 3.15%-13.82%.The inheritance of main panicle length:The trait is more complicated,there were five genetic models for main panicle length?Two combinations were consistent with the“two major genes with additive-dominant effects+polygenic with additive-dominant effects model”?Hengfengyou Huazhan,Luyou Mingzhan?,in which the heritability of major genes was 71.62%and72.50%,while the polygenic heritability was 10.01%and 8.90%.One combination was consistent with the“two major genes with additive-dominant-epistasis effects+polygenic with additive-dominant effects model”?II You Ming 86?,in which the heritability of major genes was 80.57%,while the polygenic heritability was 7.89%.One combination was consistent with“two major genes with complete dominant effects+polygenic with additive-dominant effects model”?Guang 8 You 165?,in which the heritability major genes was 70.03%,while the polygenic heritability was 13.25%.One combination accorded with“two major genes with additive-dominant-epistasis effects+polygenic with additive-dominant-epistasis effects model”?Quanyou Simiao?,in which the heritability of major genes was 75.67%,and the polygenic heritability was 9.90%.Two combinations were consistent with the“polygenic with additive-dominant-epistasis effects model”?Tianyou Huazhan,Tianyou 3301?,in which the heritability of polygenic was 52.27%and 55.18%respectively.The inheritance of grain lenth:There are four main genetic models.Three combinations were consistent with the“two major genes with additive-dominant-epistasis effects+polygenic with additive-dominant effects model”?Hengfengyou Huazhan,II You Ming 86 and Luyou Mingzhan?,the maior genes heritability ranged from 64.37%to 83.04%,while the polygenic heritability ranged from 11.18%to 25.59%.Two combinations were consistent with the“two major genes with additive-dominant effects+polygenic with additive-dominant effects model”?Guang 8 You 165,Quanyou Simiao?,and the heritability of major genes was 77.44%and85.92%,the polygenic heritability was 5.14%and 4.35%respectively.Onecombinationaccordedwiththe“polygenicwith additive-dominant-epistasis effects model”?Tianyou 3301?,and the polygenic heritability was 57.83%.One combination was consistent with the“two major genes with additive-dominant effects+polygenic with additive-dominant effects model”?Tianyou Huazhan?,the major genes heritability was 26.52%,and the polygenic heritability was 28.52%.The inheritance of grain width:as with grain length,there were also four genetic models.Three combinations were consistent with“two major genes with additive-dominant-epistasis effects+polygenic with additive-dominant effects model”?Hengfengyou Huazhan,Quanyou Simiao and Luyou Mingzhan?,in which the heritability of major genes varied 78.54%-87.18%,while the polygenic heritability varied1.74%-7.89%.One combination was consistent with the“two major genes with additive-dominant effects+polygenic additiv-dominant effects model”?Tianyou 3301?,the heritability of the major genes was 85.62%,and the the polygenic heritability was 5.01%.One combination was consistent with the“two major genes with additive-dominant-epistasis effects+polygenic with additive-dominant-epistasis effects model”?Guang 8 You 165?,the major genes heritability was 81.73%,and the polygeic heritability was 9.23%.One combination accorded with“two major genes with additive-dominant effects+polygenic with additive-dominant effects model”?II You Ming 86?,in which the heritability of major genes was 74.09%,and the polygenic heritability was 21.34%.One combination was consistent with the“polygenic with additive-dominant-epitstasis effects model”?Tianyou Huazhan?,and the polygenic heritability was 69.12%.In summary,in the strong dominant hybridization combination,except for the genetic traits of individual traits,the heterosis potential of most traits related to yield is mainly affected by 2 pairs of major genes+polygenic,and some traits have high genetic rate of major genes,most of the genetic variation was analyzed,and the genetic rate of multiple genes was low.The genetic mode of these genes was beneficial to the selection of breeding and the utilization of heterosis.