Study On The Heredity Of Kernel Protein And Lysine Content And Main Agronomic Characters In Maize In Different Ecological Conditions

ABSTRACT Main nutritional quality of 192 maize inbred lines including self-selected inbred lines and elite lines was analyzed,10 inbred lines belonging to different heterotic groups from elite lines were crossed each other by a 10×10 complete diallel cross design.15 self-selected inbred lines from 5 basic groups as female and 5 elite lines as male were crossed by NCâ…¡design.Hybrid seeds of F₁ were planted in three different ecological conditions in Henan province.Protein and lysine content of kernel by NIRS (Near Infrared Spectroscopy)and the main agronomic characters and growth stages of F₁ generation were measured.The content of protein and lysine in germplasm,F₁ and F₂ generations,the heterosis in F₁ and F₂ related with their parents and other nutritional quality were analyzed.Genetic effects of protein and lysine content and that of main agronomic characters were calculated,analyzing the effects of genotype(G),environment(E) and G×E for F₂ kernel protein and lysine content and F₁ plant main agronomic characters.The results were as below:1)In this study,the protein and lysine content were 11.42 percent and 0.37 percent, with the varied range from 8.03 to 15.31 percent and from 0.27 to 0.49 percent separately.Nutritional qualities were different with different genetic origin.The self-selected lines based on group M and "8822" had higher content of protein and lysine,the resources from the groups Z508 and Z512 had a little higher content of starch, which can be used as the parents of hybrids with high protein or starch respectively.It was possible to select germplasms from basic groups varied broadly according to different breeding goals.2)The protein content in grain was significantly positive correlation with lysine while protein and lysine were both significantly negative correlation with starch.3)The additive effect was main genetic effect for the content of protein and lysine, the broad heritability and narrow heritability for protein content were about 40 percent and 34 percent respectively,while those of lysine were about 14 percent and 13 percent. The protein and lysine content with lower heritability were influenced greatly by environment and lysine was more influenced by environment than protein.The same character showed different heritability in crosses under different genetic backgrounds.4)The inbred lines with higher GCA(General Combining Ability)of protein and lysine were NO.2,NO.3,P13,P4 and P9,while NO.10 and P3 had the lowest GCA, The crosses 3×9,1×7,1×10 and 2×4 had higher SCA(Special Combining Ability),especially 3×9 has the highest SCA in both protein and lysine characters.5)The protein and lysine showed a certain positive heterosis in F₁ generation,the heterosis of lysine was more significant than that of protein,while the heterosis declines in F₂ generation,the declining degree in protein was more than in lysine.6)The order of correlation coefficient between the content of protein and lysine in F₁ and their parents content was female parents＞mid parents＞male parents,while in F2 the correlation with male and female was not different,the correlation coefficient was the highest between protein content and mid parents,the correlation for lysine with mid parent and low parent was similar.7)The difference of protein and lysine content among different genotypes and years was significant.The interaction effect on protein and lysine content showed a certain influence,The protein and lysine content varied with latitude,appeared to be higher in north than in south in Henan province,which had affinity with local ecological and cultivated conditions.8)The main agronomic traits was affected not only by genotype but also by interaction.The additive and non-additive were both important for the dry ear weight. The heredity of other agronomic characters was additive effect mainly.The additive effect of dry ear weight,forming kernel rate,thousand kernel weight,tasselling stage, silking stage and pollen stage was mainly from female additive effect,while other traits from male.The heritability of ear lines was the highest.9)The inbred lines NO.3,NO.8,NO.7,P13,P6 and P9 had higher GCA in kernel yield,The crosses 10×9,3×5,8×10,3×9,P15×Pa,P13×Pd and P6×Pd had higher SCA. In this study,the cross with 3 and 9 as parents is a more perfect cross with both the highest protein and lysine content and higher kernel yield.