Preparation And Identification Of Early-maturing Corn Hybrid Combinations In Northeast China

Maize is a crop originating from tropical and subtropical regions.There are some problems in spring maize planting areas in China,such as late maturity and low yield.In this study,parents of maize varieties popularized in early maturity areas of Heilongjiang Province in recent years were used as the main parent materials,and crossed with 400 inbred lines of different origins at home and abroad.Through breeding in the South and breeding in the north,identification and evaluation for many years,we hope to breed early-maturing and stable yield varieties suitable for the early-maturing planting areas of Spring Maize in Northeast China.The main findings of this thesis are as follows:1.Identification of growth period and Yield Related Traits of maize parentsThrough investigating the characters of growth period,it was found that 400 parents had significant genetic diversity in male-setting,pollination-dispersing and silking stages,including very early maturity,early maturity,medium maturity and late maturity between 40 and 60 days of flowering,which was suitable for preparing active accumulated temperature between 2100 ℃~2500 ℃ The intercropping of Maize Combinations with accumulated temperature provides the material basis.2.Composition and main agronomic traits of Maize Hybrid CombinationsAccording to the theory of maize heterosis group and heterosis pattern and the idea of molecular design breeding,1000 cross combinations were made with 400 inbred lines at home and abroad.The specific combining ability analysis showed that the grain yield SCA of 420 hybrid combinations was positive.The yield of maize was positively correlated with leaf number,chlorophyll content,100-grain weight,plant height and ear position,and negatively correlated with lodging rate and tassel branching.3.Identification and evaluation of early maturing hybrid combinationsFrom 1000 cross combinations,20 early maturing combinations were screened out and identified and evaluated in Hulan District and Wudalianchi of Heilongjiang Province.The results showed that the growth period characters of 20 early-maturing hybrid combinations at two test sites were characterized by early maturity,i.e.40-47 days from seedling emergence to powder dispersal and 100-110 days from maturity.However,there was a significant difference in grain moisture content between the two experimental sites during harvest period.The measured moisture content at Hulan experimental site was less than 21%,while that at Wudalianchi experimental site was about 25%.The results of grey correlation analysis showed that there was no significant difference in the equal weight correlation degree and weighted correlation degree between early-maturing combinations such as LHD1817,LHD1801,LHD1804 and LHD1806.The comprehensive performance of early-maturing combinations was higher than that of German,American and Asian varieties,which could be used as high-quality resources for early-maturing varieties breeding in Northeast Spring Maize planting areas.