Studies On The Relationship Between Genetic Laws And Heterosis In High Oil Maize Inbred Lines

By the method of NCⅡ(6×6), with 12 maize inbred lines, 36 combinationswere made to study the combining ability, genetic parameter, correlationanalysis, path analysis and heterosis of 15 characters. Main results were asfollows:The analysis of combining ability indicated that there were significantdiferences estimates of general combining ability (GCA) on high oil inbred linesexcept for the silking and plant height. The oil content and plant yields of allcombinations didn't coincide with estimates of special combining ability (SCA),but coincide with estimates of total combining ability (TCA) for oil content andplant yields. It showed that the oil content and plant yields could be predicted bytheir TCA, and inbred lines H46 and H63 were the best general combiningability (GCA) for oil content and yield traits.Evaluation of genetic parameter revealed that the sequence of Vg(%) andVs(%) from high to low was reverse among 15 characters, and Vg(%) of allcharacters except for silking and plant height was larger than Vs(%). Itsuggested that these characters are controlled mainly by additive gene. The sixcharacters—kernel oil contents, embryo oil contents, 100-kernel weight, axisdiameter, ear diameter, sterile length, their narrow-sense heritability andbroad-sense heritability were all high, so these characters could be selected at early generations.The correlation analysis among 13 major agronomic characters indicatesthat ear weight, ear diameter, plant height, ear height, 100-kernel weight, kernelnumber per row, axis diameter to kernel weight per ear showed high significantpositive, that heading, sterile length, silking to kernel weight per ear showedsignificant or high significant negative. The correlation analysis among the mainyield character and oil contents indicates that kernel number per row to kerneloil contents showed significant positive, that 100-kernel weight, axis diameter tokernel oil contents showed significant or high significant negative.The path analyses showed that the contributions of 8 characters to kernelweight per ear were ear diameter＞kemel number per row＞plant height＞earlength＞100-kemel weight＞ear height＞row number of ear＞sterile length,among them only the sterile length had a negative direct effect on kernel weightper ear, that the contributions of 4 characters to kernel oil content were earweight＞embryo oil contents＞100-kernel weight＞kernel weight per ear,among them only ear weight and embryo oil contents had positive direct effects.The heterosis analysis showed that the hybrid of L75×H46 was the bestamong all 36 hybrids, it's kernel oil content is 10.02%, and kernel weight perear's over-standard heterosis is -2.19%. These results indicated that this hybridwill be useful in field planting in future.