| Excellent germplasm resources are the key means to select and breed improved high-yielding and high-quality maize varieties.In the present experiment,6 good populations were selected as male parent and 9 good inbreeding lines were selected as the female parent.54 top crosses were selected by using NC II genetic mating design group.Later,a randomized-area,3 replicate trial design was used to conduct a field combination trial and top hybrid combination characterization at 3 sites in one year in Xingshan County,Yichang City,we investigated the traits of plot yield,plant height,ear height,row grain size,100-grain weight,full fertility,and water content at harvest to evaluate the breeding potential of these six populations in southwest China,and thus provide a theoretical basis for future maize breeding efforts.The main conclusions are as follows:(1)The analysis of the general combining ability of the inbred lines for the main agronomic traits showed that the highest GCA effect values for yield were observed for the inbred line J9,and positive GCA values for the other yield-related traits.It is relatively easy to produce high-yielding progeny using it as a parent,with the disadvantage of a long growing period,high moisture content at harvest,and high plant and ear height.At a later stage it can be complemented by combining with the inbred line J1;The GCA effect value of yield of inbred line J4 is second only to J9,and the GCA performance of most yield related traits is good,and the use of its hybrid combination can effectively reduce the plant height and spike height of the offspring,with great utilization potential;In addition,the GCA effect value of yield of inbred lines J5 and J8 is also positive,which has certain utilization potential.Other inbred lines can be selected according to different breeding objectives,such as inbred lines J1 and J3 can be used to shorten the growth period of offspring;The inbred line J2 can be used to increase the number of rows per ear of offspring;Inbred lines J6 and J7 have the ability to reduce the plant height of offspring.(2)According to the analysis of the general binding capacity of the major agronomic traits of the groups,group T4 had the highest yield GCA value,with the merit of reducing offspring plant height and spike height by increasing 100 grain weight,spike long and rows per spike,and had the greatest utilization potential;groups T3 and T5 had a positive yield GCA effect,with the merit of reducing offspring height and spike height,shortening the growth period of offspring,and its utilization potential was large;Although the GCA effect value of population T6 is greater than 0,the value is small.It can be used to increase the 100-grain weight of hybrid offspring and reduce the plant height and ear height of offspring;In addition,population T2 has the function of shortening the growth period of the offspring and reducing the water content in the harvest period of the offspring.The comprehensive character of population T1 is the worst,and it needs to be improved before it can be used.(3)The general cooperativeness is high,its performance of the special cooperativeness is not necessarily high,for example,the general cooperativeness of the self-breeding line J9 and the group T4 are high,but the special cooperativeness of the combination obtained by crossing the two is not high,indicating that the superparental performance of the excellent combination is the result of the combined effect of the additive and non-additive effects of genes. |
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