Studies On Genetic Analysis Of Five Maize DH Lines At Lancaster Population

In this study,five Lancaster-modified DH lines were used as the male,five Reid-group inbred lines were used as the female,and got 25 combinations.The cross combinations and inbred lines were planted in 3 different density of 60,000 /ha,75 000 / ha and 90 000 plants / ha.Through combining ability,genetic parameter and path analysis,the result showed that:1.The combination T1811 × J1221 had the highest control advantage at three densities,and the yield superiority was obvious.J1221 was derived from PH4 CV × PHB1 M,T1811 was derived from PH6 WC × C8605-2.2.The GCA(general combining ability)of J1221 is better in the three densities.In yield SCA(specific combining ability)performance it also had the largest combinations of positive combining effects in three densities,which indicated that inbred line J1221 had better yield potential.And the pedigree was PH4 CV ×PHB1M.3.Genetic parameter analysis showed that plant density had little effect on genetic parameters.The generalized hereditary rate of each trait was in the following order: ear position> grain number> ear length> seed rate> panicle weight> panicle number> 100-grain weight> ear diameter> plant height> bald tip> axis roughness,that the order of narrow heritability was: ear number> ear position> seed rate> grain number> plant height> 100-grain weight> bald tip> panicle weight> panicle length> ear diameter> axis roughness.The generalized heritability and the narrow heritability of panicle number,ear position,seed yield and row number of grains were higher,and the difference was smaller,can be selected in the early generation.The generalized heritability of spike length,ear diameter,grain number,panicle weight and 100-grain weight were bigger,and the difference between broad and narrow sense was larger,which indicated that it was mainly controlled by non-additive genes and susceptible to environment.The generalized and narrow heritability of baldness and axis roughness were all small,which indicated that this trait was influenced by additive genes and influenced by the environment,which may be related to the experimental conditions.These results are consistent with previous studies.It was also proved that the changes of these genetic parameters were not influenced by density,and the results obtained in the past are still applicable under high density test.4.The results of path analysis showed that the direct effect of 100-seed weight on yield was the largest,the direct effect of bald tip on yield was negative,and the bald tip was sensitive to density,and the negative value increased with density.These two traits are the most important factors affecting yield,and these two traits should be considered during the breeding process.