| The breeding of fine inbred lines is the basis and key to the use of Heterosis and the cultivation of excellent hybrids.The haploid breeding technique based on parthenogenesis induction system(DH)is a new method for rapid selection of inbred lines.A large number of DH lines bred by DH breeding technology have not been eliminated by natural selection,but also need to determine the combining ability.In this paper,the genetic research of DH system was carried out in order to provide reference for DH breeding of maize.In this paper 82 modified PH6 WC DH,PH6 WC and WG6320 as the female parent,with corresponding heterotic groups Tong A6,Tong 694,WG5603,PHB1 M,PH4CN as the male parent,as(84 ×5)NC II genetic mating design,the main agronomic traits of heterosis,combining ability,heritability,genetic model is studied,and the average superiority,the relative value of GCA,the relative value of SCA and the observed trait mean values were correlation analysis and factor analysis.High yield combination.The results are as follows.1.The average heterosis analysis show that,The average heterosis of yield per plant of 123.92% was the highest,the variation coefficient was 23.71%,the maximum heterosis was 253.4%,the lowest heterosis was 48.5%,the variation range was big.The average heterosis of number of kernels per row was 42.77%,the ear length was 26.48%,the 100 grain weight was 19.85%,and the grain index was 4.77%,but the grams per liter was-0.18%.The average heterosis of length of bald tip was 111.87%.The plant height was 41.77% and the ear height was 54.35%.2.The combining ability analysis show that,The GCA relative value of yield per plant of the 38 materials for more than 0,accounting for 89 of parents 42.7%.In 5 the male line,only the order of PHB1 M is 27,positive.indicating that the female parent DH lines and PHB1 M is the first dominant model.Of the 82 DH lines yield GCA value relative to the above 0 to 35 copies of materials,of which 19 copies DH lines from material of the 25 copies of A67×PH6WC,accounting for 76% of the total number of the DH lines;the 30 copies of A67×L50 female material on the basis of DH lines 12 copies,accounting for 40% of the total number of the DH lines;the 27 copies of A67×KW4M029 based materials for DH lines 4 copies,accounting for 14.8% of the total number of the DH lines.illustrate the A67×PH6WC materials are improved obviously.SCA effect analysis showed that,The plant yield SCA relative value from 15.4 of 102-15×Tong694 highest combination to-20.6 of 100-17×Tong694 Minimum combination,amplitude variation is relatively large,the difference mainly comes from parents Non allelic gene of epistatic effect.The relative value of ear length SCA,the relative value of number of kernels per row SCA,the relative value of 100 grain weight SCA were relatively large difference,the relative value of grain index SCA and grams per liter SCA were relatively small difference.3.The genetic parameter analysis show that,The generalized heritability of yield per plant was 15.34%,and the narrow sense heritability was 11.28%.the narrow sense heritability was higher than 50% of plant height,ear height,days from emerging to tasseling,days from emerging to silking and ASI,number of rows per ear,number of kernels per row,100 grain weight and grams per liter.the narrow sense heritability was slightly less than 50% of ear length,grain index.4.The genetic model test show that,The results of that only ASI,grain index and seedling SPAD value in the 18 traits were consistent with the Additive-Dominance model.The other 15 traits did not conform to the Additive-Aominance model.The genetic model of plant traits and developmental traits was mainly A-D-E.The yield per plant,ear length,kernel number per row,ear row number and 100 grain weight were all Additive genetic models.5.The correlation analysis show that,The yield per plant was very significantly positively correlated with plant height,was significantly positively correlated with ear height,and heterosis of correlation is very significant and positive expression,so that is mainly controlled by GCA relative value correlation effects,Plant height,Ear height too higher easily lead to lodging.To reduce maize plant height and ear height,First reduce parents plant height and ear height,in order to achieve the fusion of high yield,low plant height and low ear height.The yield per plant was very significantly positively correlated with ear length,kernel number per row,100 grain weight and grams per liter.The advantage of the correlation,the yield per plant and ear length,kernel number per row and 100 grain weight was very significantly positive correlation,with grams per liter was significantly positive correlation.that the relationship between the yield per plant and ear length,kernel number per row,100 grain weight and grams per liter,was influenced by GCA and SCA relative correlation value.therefore,the increase of ear length,kernel number per row,100 grain weight,and grams per liter,can improve the yield per plant.The yield per plant and teh SPAD value tassel stage was extremely significant positive correlation,It showed that the SPAD value tassel stage can be used as an important index to evaluate the combination and inbred lines.The yield per plant and grain index,number of rows per ear positive correlation did not reach significant level,indicating that influenced by GCA relative values and SCA relative value correlation.So the selection parents of hybrid should focus on the high grain index of the material.6.The factor analysis show that,The factor analysis of 18 traits showed that plant height,ear height,ear length,ear row number,kernel number per row was 1,which was the basis for increasing the yield per plant,and was the most important combination selection index.The seedling stage,tasseling stage,silking stage and grain index factor of 2,reflecting the characters of development and relationship between grain index,is the important developmental screening index of combination.The factor 3 of the SPAD value of the leaves at the seedling stage,jointing stage and tasseling stage is an important physiological index to increase the yield per plant.The factor of 100 seed weight and ASI was 4,which was the key factor to increase the yield per plant.7.The combinations of runoff show that,The runoff 12 from 420 combiantions,accounting for 2.9% of the total combination of DH lines.There were six of DH lines of Selected combination source on the A67×PH6WC materials,accounting for 24% of its total number of DH lines,there were two of DH lines of source on the A67×L50 female materials,accounted for 6.7% of its total number of DH lines,there was one of DH lines of source on the A67×KW4M029 materials,accounting for 3.7% of its total number of DH lines.The results show that the A67×PH6WC as the base material is improved,and the GCA high DH system is more,which is a good base material. |
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