Study On The Heterotic Group Of Maize Inbred Lines In Henan Province With SRAP Molecular Markers Technology

The materials used in this study were 29 maize inbred lines utilized in Henan since the 1980's, of which the genetic diversities and heterotic groups were studied by SRAP molecular markers the first time, also the SRAP molecular marker technology of maize was optimized. This research also analyzed the heterotic patterns of the popularized maize hybrids in Henan and their parents'genetic distance. The main results showed:1. The SRAP-PCR system of maize was established. The PCR processing of SRAP in maize was: initially denaturing at 94℃for 5 min, 94℃,1min, resumed denaturing at 35℃for 1min, 72℃, 1min for the first 5 cycles. Then 94℃, 1min, 50℃, 1min, 72℃, 1min for next 35 cycles. Finally denaturing at 72℃for 10min. the optimum concentrations of DNA template and Mg2+ were 20ng for 25ul DNA and 2.0mmol/L. Amplified results of this system were fully reproducible and good stability, and the Polymorphism chart of maize was abundant.2. twenty-nine inbred lines were classified into four groups based on the analyzed results of SRAP, of which groupⅡwas divided into two sub-groups, groupⅢwas three sub-groups, and the twenty-nine inbred lines were also divided into seven sub-groups. GroupⅠwas scarlet colony, including Zheng22, Zheng35, 9212, Dan340, E28; groupⅡwas heterotic colony from America, including 87-1, Zheng36, P138; groupⅢ-1 was a idioplasmatic colony containing characters of maize in low latitude, including Shen219, 9058, 248; groupⅢ-2 was meliorated Reid colony, including Zheng13, Zheng29, An246, Zheng60, Zheng58, 478, 9404, Xin4(white), Bai107, Zong3; groupⅢ-3 was Tangsipingtou heterotic colony, including Jun92-6, Jun92-8, Xin7(red), Chang7-2,Jing7(yellow); groupⅣwas Lan heterotic colony, including Xu052, Luo12. The clustering result was consistent with the grouping based on the available pedigree. Average genetic resembled coefficients among groups were smaller than that within groups, which showed the classification was reasonable. Most of the parents of popularized maize hybrids came from different groups or sub-groups. So SRAP markers could be applied to classification.3. Genetic distances among 29 maize inbred lines were calculated with SRAP markers. Relations between molecular marker distances and heterotic patterns were analyzed through the heterotic parents and their parents'genetic distances which were popularized at present. The results showed: genetic distances of most high yield heterotic parents were longer than that of the average, that is genetic differences between inbred lines were bigger. But some genetic distances between inbred lines were shorter than that of the average, such as Xinhuangdan90-4, Baiyu109, Jundan20, Zhengdan21, Zhengdan22. Though parents'genetic distances pointed by us were not the biggest, most of which were longer, the shorter ones of inbred lines didn't match high yield products. It could be concluded that genetic distances of SRAP marker had definite relations with heterotic patterns, but SRAP marker couldn't predict heterosis exactly.