Study On Combining Ability And Heritability Of Oil Percentage And Fatty Acid Composition In Micro-endosperm Corn

Micro-endosperm corn is a new kind of high oil corn germplasm.The main goal of breeding high oil corn is to improve the oil percentage and the quality of corn oil.The main task of breeding high quality corn oil is to improve the content of unsaturated fatty acids,especially the content of oleic acid.In order to study the genetic law of fatty acids and the relationship between fatty acids and oil percentage,two micro-endosperm corn inbred lines with high oleic acid and high oil percentage and six micro-endosperm corn inbred lines with low and medium oleic acid and low oil percentage were selected in this experiment,and 12 cross combinations of micro-endosperm corn were designed according to NC Ⅱ.The yield characters,oil percentage,crude protein content,fatty acid composition and other quality characters were measured,and the combining ability and genetic parameters were studied.The main results were as follows:(1)Character performance.Among the 12 crosses,combination 1,combination 7 and combination 9 showed better yield character performance,while combination 3,combination 4,combination 5 and combination 6 showed worse yield character performance.The oil percentage of 12 crosses was 24.54%-28.95%,and the crude protein content was 27.67%-33.33%.In terms of fatty acid composition,oleic acid content is 42.67%-47.8%;linoleic acid content is31.9%-40.93%;linolenic acid content is 0.64%-0.79%;palmitic acid content is 10.85%-14.5%;stearic acid content is 3.08%-4.44%;linolenic acid,arachidonic acid,arachidonic acid,behenic acid,pyrooleic acid,palmitic acid and heptanic acid content are all less than 1%.The oil percentage,protein content and oleic acid content of combination 11 and 12 were better.(2)Combining ability analysis.Among the parents with high oleic acid and high oil percentage,there were 11 characters with significant or extremely significant GCA variance F value,while the GCA variance F value of the five characters of row number,crude protein content,oleic acid content,linoleic acid content and peanut acid content was not significant.In the parents with low oil percentage and low oleic acid content,except the GCA variance F value of peanut acid content did not reach a significant level,in the other 15 characters:the F value of GCA variance was significant or extremely significant.The variance F value of SCA in four characters of oleic acid content,linoleic acid content,stearic acid content and lignoceleic acid content were significant or extremely significant.The hybrid combination of parents with higher GCA showed better performance.The relative effect value of GCA of four characters with significant GCA variance and SCA variance was the same as that of each character.(3)Genetic parameters.Except for the broad heritability of kernels in ear row 45.91%,the rest of 14 characters’ broad heritability were more than 65%indicating that these characters of micro-endosperm corn are greatly influenced by heredity and less affected by environment.Except for the low heritability in narrow sense of oleic acid content and linoleic acid content,the narrow heritability of the other 13 characters were all above 42%.The variance of general combining ability of linoleic acid content and lignoceleic acid content was less than 25%.The non-additive effect of these two characters played a great role.The variance of general combining ability of oleic acid content was52.56%,indicating that additive effect and non-additive effect played the same role.The variance of GCA of the other 12 characters was more than 80%.Among these characters,additive effect played a greater role.(4)Correlation analysis of main characters.Among the six yield characters,there was no significant positive correlation between 100-kernel weight and kernels in row,and there was significant or extremely significant positive correlation between the other yield characters.There was a negative correlation between oleic acid content and kernel weight per ear,but the correlation was not noticeable.If the aim of breeding is to increase the content of oleic acid,the yield will not be significantly affected.There was no significant positive correlation between the content of oleic acid and the content of crude protein and oil percentage,but a significant negative correlation between the content of oleic acid and the content of linoleic acid.Path analysis showed that the direct influence of the five factors on the oil content per ear from big to small: kernel weight per ear> oil percentage> linoleic acid content> rough protein content>oleic acid content.Among them,the direct effect of oleic acid content has minimal negative effect,and the direct effect of the other four characters have positive effect.There was a significant positive correlation between the kernel weight per ear and the oil content per ear,and the path coefficient of grain weight of single ear was also the maximum value,which indicated that increasing the grain weight of single ear was the best way to increase the oil content per ear.