| In the study die material were 15 elite inbred lines in Sichuan and 105 crosses combined by 15 inbred lines. 15 elite inbred lines were studied by agronomic and economic trails observation analysis and cluster based on SSR markers. 105 crosses were made according to 4th method of Griffing's to analyze general combing ability (GCA) and special combing ability (SCA). The results as following:1. GCA and SCA variance of ear length, sterile length, ear diameter, axis diameter, rows per ear, kernels per row, kernels per ear, ear weight, axis weight, plant yield, 100-kemel weight, shelling percentage, unit weight, interval between anther and silk, plant height and ear height were significant at 0.01 level. Inbred line 18-599, 7327, 698-3, S37 and 48-2 had better comprehensive GCA of average plant yield and other trails contributing to plant yield. Cheng687 x 7327 had highest plant yield SCA and 156 x 18-599 had lowest one. Plant yield SCA variance ranged from 216.97 to 672.47, and inbred line 32 and 156 had largest and smallest variance respectively. In aspect of plant yield total combing ability (TCA), 18-599 x 7327 had maximum value and ye478 x 5003 had minimum. So, the author thought inbred line 18-599 and 7327 performed better judged by high plant yield, high plant yield SCA and wide variance range of plant yield SCA, and high plant yield crosses could probably be screened from crosses combined by the two inbred lines. Other inbred lines had their own advantages and could be used in different breeding aims.2. The genetic distances (GD) of 15 inbred lines were calculated based on data of 17 trails. GD range (from 1.428 to 11.573) and average GD (5.473) showed more genetic morphology among studied materials. 15 inbred lines were classified into 4 groups: group I including 5003, qi205, ye478, 32, 77-5, 7922, group II including cheng687, S37,156, 18-599, 200B, zi330, 7327, group in including 48-2 and group IV including 698-3. To some degree, the cluster partly agreed with known pedigree, but there were some differences between them. The reason probably had connection with trails selection and interaction between trails and environment.3. Cluster analysis was taken by shortest distance method based on plant yield SCA as genetic distance. 15 inbred lines were approximately classified into 4 groups: group I including 32, 7922, ye478, 5003, group II including 156, 18-599, cheng687, 7327, 200B, zi330, 698-3, 48-2, S37, groupIII including qi205 and groupIV including 77-5 .Cluster result of plant yield SCA partly agreed with pedigree, but there were some difference between them. The reason was deduced to be largely connected with interaction between gene and environment.4. Genetic distances of 15 inbred lines were calculated based on SSR analysis data. Although average GD (0.313) was smaller, wider GD range (from 0.167 to 0.488) showed higher genetic morphology among studied materials. In this cluster result, 15 inbred lines were classified 4 groups: group I including 7922, 32, 5003, ye478, group II including 7327, 200B, zi330, 156, 18-599, 77-5, 698-3, cheng687, group III including 48-2 qi205 and groupIV including S37. The result approximately agreed with pedigree and previous researches, but there were still some difference.5. According to plant yield of hybrids and cluster based on SSR markers, combiningpatterns of 12 maximum plant-yield crosses in this study were subgroup Mol7 x subgroup zi330, subgroup Mo 17 x subgroup germplasms from foreign hybrids, group ludahonggu x subgroup zi330, subgroup zi330 x subgroup germplasms from foreign hybrids, subgroup Mo 17 x group unproved Reid, subgroup zi330 x group tropical germplasms, group ludahonggu x subgroup Mol 7, subgroup Mol 7 x group tropical germplasms and subgroup germplasms from foreign hybrids x group tropical germplasms. Heterotic patterns of 8 popularized strains combined by 15 inbred lines were group improved Reid x subgroup zi330, group improved Reid x subgroup Mo 17, group improved Reid x group tropical germplasms, subgroup zi330 x subgroup... |
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