Combining Ability And Heterosis Group Analysis For 5 Maize Inbred Lines Bred By The Agriculture Science Instite Of Yili, Xinjiang

Five maize inbreds lines`combination ablity and heterosis group were studied in this study, and Giffing method 4(model I) was useded to hybrid the 55 hybrid combinations. The study can help to improve the utilization of inbred lines, and provide the reference for the reasonable use of maize breeding and germplasm resources of Yili valley. The main results were as follows:1. The heterosis groups and heterosis model of the fourteen Yidan maize hybrids and three introducted hybrids into Yili valley were analyzed, and the results indicatedthat the main heterosis groups in Yili valley is Reid, Lancaster group, Sipingtou group and that Lvdahonggu, and the comprehensive varieties were used less. The main heterosis utilization modes is Reid x Lancaster, followed by Reid x Sipingtou group, then the Reid x synthesis of subgroup, and the last two modes has a certain development trend in Yili valley in recent years.2. The 12 argiculture characters, such as plant height, ear height, stem diameter, ear length, ear diameter,sterile length, axis diameter, rows per ear, kernels per row, shelling percentage, 1000-kernel weight, yield per plant have significant differences between the 55 hybrid combinations hybred by the five inbred maize lines and the six standard test maize inbred varieties. The 503-412 is the best among the 5 inbred lines,followed by Y331, Y314, 242-B84. The top 10 combinations with yield per plant among the 55 combinations were Y314×Mo17、242-B84×Y331、Mo17×242-B84、503-412×Y178、Zheng 58×Y178、503-412×Ji 853、242-B84×Ji 853、Chang7-2×242-B84。3. The estimation of genetic parameters of agriculture characters showed that: the broad heritability and narrow heritability of plant height, ear height, stem diameter, ear diameter, rows per ear, kernels per row, 1000-kernel weight are higher than 50%, and the additive variance is greater than the dominant variance, and they were affected less by environments and it is appropriate to be selected in early generations for these traits. The broad heritability of stem diameter, ear length, sterile length, ear diameter,yield per plant are more than50%,but their narrow heritability were lower than 50%, and these traits are unfavorable to be selected in early generations. The additive variance of axis diameter, sterile length, yield per plant were all lower than the non-additive variance, and the the additive variance of stem diameter, ear length and shelling percentage were all higher than the dominant variance.4. The correlation analysis showed that the correlationship with the production of per plant decreased from ear length, ear diameter, 1000-kernel weight, shelling percentage, rows per ear, ear height, axis diameter, kernels per row, plant height, sterile length, stem diameter accordingly. The correlation index of ear length, ear diameter, 1000-kernel weight, shelling percentage is 0.98, 0.88, 0.85, 0.8 accordingly, and they are significant at 0.01 leve. The rows per ear is significant correlated with the production of per plant at 0.05 levels, the correlation index of other traits with the production of per plan were not significant. Path analysis shows that the direct contribution of test traits to yield per plant decreased for rows per ear, kernels per row, ear length, plant height, axis diameter, stem diameter, sterile length, ear height, 1000-kernel weight,shelling percentage, ear diameter, accordingly. The rows per ear to the yield per plant is 0.8,and which is significant at 0.05 level, kernels per row to the yield per plant is 0.8 and is significant at 0.05 level, ear length to the yield per plant is 0.4 and is significant at 0.05 level.5. The inbred line heterosis groups and heterosis model analysis results shows that the inbred line242-B84 and 503-412 belong to the classⅠReid group, and Y331 belongs to the classⅡthe Lvdahonggu;Y178 belongs to the class Ⅲ Lancaster group; Y314 belongs to the class Ⅳ Tangsipingtou. The hybrid heterosis model Reid x Lancaster group is better than Reid group x Tangsipingtou group, then the Tangsipingtou group x the Lancaster group.