| Corn is an important food and feed crop.It is also the grain with the largest planting area,the highest absolute yield and the largest potential to increase production in the world,and the largest crop in our country.The average yield per unit area of corn in China is about 6450kg/hm~2,and the highest yield per unit area is only 24948 kg/hm~2,which has a big gap with the United States.Creating high combining ability maize inbred lines and cultivating maize varieties with high yield,high quality and strong resistance to stress is the fundamental way to increase maize yield.The study of the chromosome regions where the key genomes of high combining ability inbred lines are located could provide genetic basis and technical shortcut for the creation of high combining ability inbred lines.In this study,the high combining ability inbred line‘966-14’and its derived lines created by the maize research team of Chongqing Three Gorges Academy of Agricultural Sciences were used as key test materials.Based on the identification of characteristics phenotype,combining ability researched,whole genome sequenced and bio informatics analysis were conducted,and the following results were obtained:1.The results of phenotype cluster analysis showed that inbred lines derived from‘966-14’had great similarity with the parental inbred line‘966-14’in morphological characteristics,quality traits and main quantitative traits.2.Results of combining ability to be studied showed that The parental inbred line‘966-14’and its derivative lines‘04942’,‘0714’,‘12612’,‘1422’,‘1423’and‘14212’had higher general combining ability,moreover,it was also good of their special combining ability to cross with the specific inbred line,which could belong to high combining ability inbred line.The corresponding parental inbred lines‘966-2’,the descendant derived lines‘0712’,‘04941’,‘1261’and the grandchild line‘1428’should belong to the low combining ability inbred lines.3.Results of the heritability to be analysis showed that the narrow heritability of plant height,ear height,ear length,number of grains per row and 100-grain weight was higher,but the narrow heritability of ear diameter and number of rows per ear was lower.When the inbred lines were created by using‘966-14’and its derivatives as basic materials,in the lower generation,we should pay attention to select the variant individuals with shorter plant and ear,longer ear,more row kernels,larger grain size and higher 100-grain weight,and in the higher generation,we should select the variant individuals with coarse ear and more row numbers.4.Results of the genome to be sequenced showed that there were 18 DNA segments on chromosomes 1,2,4 and 10 of parental inbred line‘966-14’,which were identical with the DNA sequences of the known model inbred line‘B73’same section.The high combining ability derived lines‘04942’,‘0714’,‘12612’,‘1422’,‘WZ142-31111’,‘WZ142-12-411-11’in the same locus of chromosome 1,2,4 and 10had highly homologous DNA fragments with‘966-14’on chromosomes 1,2,4,10.Twenty-two key SNPN and 169 genes were found on the 18 section of chromosome 1,2,4 and 10 of‘966-14’,among them,68 genes were expressed specifically in the root,stem,leaf,pollen,filament and kernel of maize,respectively,most of the specific genes were highly expressed during root and seed development.Which indicated that 68 genes in 18 genomics regions chromosome 1,2,4 and 10 of‘966-14’could be the key genome related to high combining ability of‘966-14’. |
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