| Ten maize inbred lines with different starch percentages were crossed in a diallel mating design in 2005. Parents and their 90 hybrids were grown in a randomized complet block design experiment in Ya'an, Sichuan province and Yuan jiang Yunnan province in 2006, respectively. the starch component of grain samples were assessed by near infrared reflectance spectroscopy(NIRS). In combined variance analysis, we analyzed the effects of the genotype (G), environment (E), and G×E on starch component. The GCA, SCA and heterosis effect on starch content were studied by the models which were applicable to endosperm characters. Finally, the genetic model of starch concentration was analyzed. And the results indicated that:1. The difference of starch content between two places reached 0.01 probability level. The average starch content of hybrids in Yunnan province was higher than that in Sichuan province by 0.42%. The difference of starch content among genotypes also reached 0.01 probability level, ranging from 68.92% to 72.87%. And the interaction between location and genotype was notable.2. Analysis showed that the GCA variance and SCA variance of starch content were notable in both locations. In Sichuan province, CX2435, CX2022, FC1003, CX2395, 08-641 and Hai-5-xuan had positive GCA effect, thereinto, CX2435,CX2022 and FC1003 reached 0.01 probability level. The crosses whose positive SCA effect were notable include CX2435×FC1003(1.68), 18-599×CX2022(1.30), FC1003×CX2435(1.17), 48-2×CX2435(1.04), 08-641×CX2395(0.81), 48-2×FC1003(0.80), W-3×CX2395(0.79), Hai-5-xuan×CX2395(0.78), 08-641×CX2022(0.78) and 08-641×Hai5xuan(0.73). In Yunnan province, CX2435, FC1003, CX2395, 08-641 and W-3 had positive GCA effect, thereinto, CX2435 and FC1003 reached 0.01 probability level. The crosses whose positive SCA effect were notable include CX2395×CX2435(0.99), W-2×48-2(0.93), 08-641×18-599(0.91), W-2×CX2022(0.89), W-2×FC1003(0.89), 18-599×08-641(0.87). CX2435, FC1003, CX2395 and 08-641 whose starch content were high had steady GCA effect in two places, especially CX2435, and high starch content crosses could probably be screened from crosses combined by it.3. Starch content showed positively and relatively low average heterosis. However, significant differences in magnitude of the heterosis were observed among combinations and locations. In Sichuan province, the average heterosis was 0.62, which was very notable. As for variety heterosis, CX2022 was highest, reaching 0.01 probability, next was CX2395, and W-3 was the lowest. CX2435 had the highest variety effect, next was W-3, CX2395 was the lowest. In Yunnan province, average heterosis was not notable. As for variety heterosis, 08-641 was the highest, next was 18-599, W-3 was the lowest. However, W-3 had the highest variety effect, next was CX2435, CX2022 was the lowest. The range of special heterosis at two places was-1.98～1.57 and-1.19～1.56, respectively, about 50% and 82% crosses had positive special heterosis at two locations.4. Coefficients of protein content,oil content and starch content were negatively correlated. Coefficients of ear length, kernels per row, kernel length and yield per plant to starch content were not notable. Ear diameter and ear rows show negative correlation to starch content. Specially, 100 seeds weight and grain production have significant positive direct effect to starch content.5. Results of 3N genetic model analysis revealed that the inheritance of starch content was in agreement with additive-dominant model, and there was no epistasis. The dominant gene effects played predominant role in the genetic variation of starch content, the dominant variation component was 45.368. The genes controling starch content had different dominant direction according to the loci.
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