| In this paper,100 waxy maize inbred lines with different genetic backgrounds were selected as test materials,and two methods of phenotypic clustering and SSR clustering were used to classify them.The 100 inbred lines were divided into four groups according to phenotype clustering,and the 100 inbred lines were divided into five groups by SSR cluster analysis,and the differences between the two kinds of cluster analysis were compared.The results of phenotypic cluster analysis and SSR cluster analysis were combined to select 15 inbred lines from each group as parents,and prepare 54 hybrid combinations according to the incomplete dial hybrid method(9×6).The parents and the hybrid generation were subjected to heritability analysis,heterosis analysis,combining ability analysis,principal component analysis,and grey correlation analysis,and excellent hybrid combinations were screened out.The test conclusions are as follows:(1)Perform phenotypic cluster analysis on 8 traits including plant height and ear position of the tested inbred lines,and divide them into four groups.The first category has 12 materials,the second category has 38 materials,The third category has 7 materials and the fourth category has43 materials.(2)15 pairs of primers detected 68 allelic variations in 100 waxy maize inbred lines,and the variation range of allelic variations detected by different detection points was 3-6.The number of alleles was 4.53.These inbred lines were divided into 6 major groups using the UPGMA method.(3)The generalized heritability of the 17 traits ranged from 70.88% to 98.72%,and the order from large to small was powder period> tasseling stage> silking stage> plant height> ear height>ear length> tassel length> tassel branch number > ear weight >corn cob weight > ear width> grain per row > 100-grain weight > rare tip length > corn cob width > ear row number > stem diameter.The range of heritability in the narrow sense is 20.21%～68.19% in descending order: ear row number> ear height>corn cob width > silking stage > tasseling stage > powder period > corn cob weight> ear width > rare tip length >tassel branch number > tassel length > ear length > plant height > grain per rew > 100-grain weight > stem diameter > ear weight.The tasseling stage,the silking stage,the powder period,the ear height and the ear length have higher heritability in both the broad sense and the narrow sense,and can be selected in the early generation.Those with low generalized heritability and narrowed heritability include stem diameter,corn cob width,100-grain weight,rare tip length and grain per row,so it should not be selected in the early generation.(4)Heterosis of waxy maize is ubiquitous in the first generation of hybrids,and except for bald tip length and shaft thickness,the positive part is greater than the negative part of the other traits,whether it is average heterosis or over parent heterosis.This indicated that among the 54 hybrid combinations of the 15 parents selected in this experiment,there were a batch of dominant combinations.In terms of fresh ear yield,the hybrid combination S07×S10 had the best average heterosis and over parent heterosis,and A52,A42,A27,A22,A48,and A39 had higher heterosis among 15 traits.(5)The variance analysis of combining ability of 17 traits of 15 parents shows that the general combining ability(except ear weight)of the parents has reached a very significant level,and the special combining ability(except the number of ear rows)of each hybrid combination has reached significant or extremely significant level.Among the 15 parents,S01,S09,S10 and S13 had better comprehensive performance,and they could be used to breed new fresh waxy maize varieties.A10,A38,A39,A41 and A43 were the combinations with higher SCA effect value.Most of these combinations had better characters and were excellent combinations.(6)The correlation analysis of the main characters of waxy maize showed that the correlations between the fresh ear yield and the main characters were in the following order: ear weight > corn cob weight > ear length> ear width > tassel length >corn cob width > ear row number > ear leaf area > grain per row>plant height>tassel branches number>stem diameter>ear height>100-grain weight> silking stage> powder period> tasseling stage> rare tip length.Many traits such as ear weight,corn cob weight,ear length and ear width all achieved extremely significant positive correlations,and traits such as ear length,ear width,ear row number,and grain per row could be used to increase fresh ear yield.(7)Grey correlation analysis was carried out on 9 panicle traits and crude starch content.The results showed that the correlation degree between panicle traits and crude starch was grain per row >rare tip length > 100-grain weight > ear length> ear width > ear weight > ear row number >corn cob width> corn cob weight.(8)Stepwise regression analysis was performed on 9 main agronomic traits,and factors with no significant effect were eliminated to obtain the optimal regression equation for fresh ear yield.Y=-22018.086+3.912X3+580.205X4+3615.391X5-402.255X6+192.675X7(9)Principal component analysis was carried out on the main characters related to fresh ear yield,and four principal components were extracted.According to the scores of principal components,combination A43 had the highest comprehensive score. |
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