Combining Ability And Genetic Diversity Among 13 Maize Populations

The narrower genetic background and lower efficiency to use maize germplasm has become a big challenge in quick development of modem maize breeding efforts and utilization of heterosis in maize production. Maize populations possess broader germplasm bases and greater variability than inbred lines, and sometimes maybe possess some special satisfied genes. Study on the heterotic groups and patterns among maize populations is an important part in germplasm evaluation.The materials in the current study included 7 domestic and 6 CIMMYT maize populations with good agronomic traits and higher yield according to the results of heterotic grouping and combining ability analysis of 27 populations conducted in 2002. Seventy-eight diallel crosses were produced following the mating design of Griffmg IV, and a minimum of 40 tassels selected arbitrarily from each population was used as male and female. The diallel crosses were tested in α-lattice design (9x9) and sixteen traits were evaluated. A pooled ANOVA over 5 locations and 2 years was calculated. Estimates of GCA, SCA, yield and reference heterosis were calculated based on the means of crosses. The genetic diversity among 13 populations has been evaluated by using 75 pairs of SSR primers for 4 bulk of DNA samples each attracted from 10 random individual plants equally. The main results were summarized as follows:1, The estimates of GCA effects on 16 traits showed that the population Jilin Syn A, Syn Liaolv, CSyn 5, Suwan 1, Pob43 and Pob21 possessed higher yield and good performance of traits. Jilin Syn A expressed higher performance of GCA effects as shelling percentage, barren tip, ear length, and kernel number per row. Syn Liaolv had higher GCA effects as shelling percentage and ear setting. CSyn 5 had higher GCA as 100-kernal weight, shelling percentage, and ear diameter. Suwan 1 expressed higher GCA effects as 100-kernal weight, ear length, ear diameter and grain moisture. Population 43 had higher GCA effects as 100-kernal weight, ear length and ear diameter. Population 21 had higher 100-kernal weight GCA effect.2, The results of a comparison of yield GCA effects between domestic and CIMMYT populations indicated that domestic populations showed higher or comparative yield GCA effects than CIMMYT populations; the results of a comparison of yield GCA effects between normal maize and QPM populations revealed that QPM populations had lower yield GCA effects than normal maize populations.3 , The results of yield SCA effects, yield and reference heterosis revealed that there was higher level of heterosis between domestic and CIMMYT populations. The level of the heterosis is higher than that of the heterotic pattern LancsterxReid, than the yield of the modern maize hybrids used in 1990s,...