| Maize is the second large crop in China. The heterotic application in maize breeding makes a great contribution to increase maize production since 1960 in China. The classification of heterotic groups is an important fundamental work in maize breeding, which can benefit not only to the combination of outstanding hybrids but also the improvement of elite inbred lines. The recent development of the molecular biological technology not only offers the new method to classify the heterotic groups but also provides the new idea on prediction of maize heterosis with molecular markers. Coix, a close relative plant to maize, has many advantages, which is considered as a useful germplasm to improve maize. Comparative genome study between coix and maize can make great sense on exploiting coix gene resources, improving crops and shedding some light on maize origin and evolution.In this study, 41 inbred lines used widely in South China and 4 inbred lines come from U.S. Corn Belt were chosen for RFLP analysis. 3 restriction enzymes and 54 probes covering 10 maize chromosomes were employed. A set of 132 single crosses were made using 33 inbred lines with 4 testers according to NC-n method. And the field experiment was conducted in two years at the same place. The objectives were: (1) to classify the heterotic group based on the yield SCA and RFLP diversity; (2) to investigate the correlations between general genetic distance and general heterozygosity based on RFLP vs. FI performance and SCA respectively; (3) to investigate the correlations between the FI performance and the special heterozygosity based on relative markers selected with ANOVA; (4) to use BLUP (Best Linear Unbiased Prediction) method to predict maize heterosis.A Fz segregation population of coix was also used as the mapping population. On the basis of constructed AFLP genetic map, 188 maize RFLP probes were analyzed, and five agricultural traits were measured in two years at the same place. The objectives were: (1) to construct a frame map covered the whole genome with RFLP marker integrated with the AFLP map in coix; (2) to map QTL of plant height, leaf length, leaf width, tassel length and stem diameter; (3) to analyze the sytenty and colinearity among coix, maize and rice through the rice database based on RFLP homologous.The results were as followed:1. According to SCA, five heterotic groups were classified among 33 inbred lines. The first group included 13 inbreds, and their SCAs with Huangzaosi were all negative; The second group included 3 inbreds, their SCAs with Huangzaosi were all very low, andtheir SCAs with Mo 17 were quite higher; The third group has 6 inbreds, their SCAs with Dan340 were all negative, but their SCAs with Huangzaosi were all positive; The fourth group had 8 inbreds, and most of these were related to U.S. germplasm. Their SCAs with Mol7 were lower, The fifth group had 3 inbreds, and their SCAs with Zi330 and Dan340 were all negative, but their SCAs with Huangzaosi and Mo 17 were all positive.2. A total of 860 bands were detected among 45 inbred lines through RFLP analysis, the number of allele at each locus ranged from two to nine with an average of 4.26. According to RFLP data 45 inbred lines were classified into Tropic group, Mo 17 group, FRB73 group, Local group I, Local group II and 330 group with Ward's cluster method. They were. The results indicated that local maize germplasm plays important role and Mo 17 group, FRB73 group, and Oh43 group which came from U.S have great effects on heterotic application in China,3. The general generic distance (GGD) and general heterozygosity (GH) vs. FI performance respectively for some yield traits, such as ear kernel weight (EKW), were lower positive correlations and highly significant, the correlation coefficients of GGD and GH vs. EKW were only 0.414 and 0.431, and the correlation of GH vs. FI performances among heterotic groups was higher (r = 0.566**) than those between different heterotic groups (r = 0.272**). Almost all of the crosses with low GH (less than 0.60) pe...
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