Analysis Of The Genetic Relationship Between Maize Parents And Their Hybrids In Grain Dehydration Rate

Maize is one of the most common cereal crops in China,which plays an important role in China’s grain production.With the labor shortage and the increase of production cost,direct harvest of maize grain has become a general trend.The grain water content is the key problem that restricts the mechanized harvesting of seeds.In order to select a variety with fast dehydration rate and suitable for direct grain harvest,NSS male parent and SSS male parent were matched with SSS line female parent and NSS line female parent respectively.The relationship between the grain dehydration rate of the same male parent and different female parent was analyzed and compared,and the combining ability analysis and genetic parameter estimation were carried out.The main results are as follows:1.Among the 4 paternal materials,the grain dehydration rate of the NSS male parents was higher than the SSS male parents,and the grain dehydration rate of NSS-T01 was the highest of 2.24(%/d),SSS-T02 had a minimum grain dehydration rate of 1.70(%/d).Among 401female parent materials,the average grain dehydration rate of NSS female parent was higher than that of SSS female parent,and the coefficient of variation of grain dehydration rate of NSS female parent was smaller.2.The difference in grain dehydration rate among hybrid combinations of different types of male parent materials reached a very significant level,and the grain dehydration rate of hybrid combinations of SSS male parent combinations was higher,with an average value of0.5913(%/d).The grain dehydration rate of the hybrid combinations composed of different male parent materials of the same type also showed extremely significant differences.The average grain dehydration rate of the 213 hybrid combinations obtained from NSS-T04 as the male parent in the male parent of the NSS line was higher;the average grain dehydration rate of the 188 hybrid combinations obtained from the SSS-T02 as the male parent in the male parent of the SSS line was higher.3.The grain dehydration rate was significantly negatively correlated with bract tightness,100-grain weight,and grain width,and was significantly positively correlated with the number of ear rows,and had little correlation with other traits.From the perspective of the correlation coefficient,the grain dehydration rate was most affected by the tightness of the bracts,and the more compact the bracts,the lower the grain dehydration rate.4.Principal component analysis results showed that the eigenvalues of the five principal components are greater than 1,and the total cumulative contribution rate was 72.83%,which basically represented the genetic information reflected by the 15 agronomic traits.The first principal component could be parsed as an ear weight factor,the second principal component was positively correlated with the grain thickness,the third principal component had the largest weight coefficient for the grain width,the fourth principal component was positively correlated with the bract’s tightness,and the fifth principal component was shelling percentage.Among the five principal components,the first two principal components were positively correlated with the grain dehydration rate,and the last three principal components were negatively correlated with the grain dehydration rate.5.The highest general combining ability(GCA)of grain dehydration rate was SSS-T02,and the lowest was SSS-T01.Among the female parent materials,NSS-84 has the largest value of GCA of grain dehydration rate,while NSS-138 and NSS-142 was the lowest.Among all 802hybridize combinations,395 of them had a positive effect on the special combining ability(SCA)of grain dehydration rate.The hybridize combinations with better performance were NSS-82×SSS-T01(0.53),NSS-26×SSS-T01(0.53),SSS-56×NSS-T04(0.58).There were 17others hybridize combinations with SGA of grain dehydration rate greater than 0.4,which would have a certain application prospect.There was a significant positive correlation between the phenotypic value of grain dehydration rate in hybrid combinations and the sum of parental GCA effects(P<0.01),and the correlation coefficient was greater than 0.5.The results showed that there was a linear relationship between the total combining ability effect and the grain dehydration rate of the hybrid combinations,and the coefficient of determination(R~2)was 1,which indicated that the grain dehydration rate of the hybrid combination was affected by the general combination effect of the parents and the special combining ability effect of the hybrid combinations.6.The additive variance of SSS lines were greater than that of NSS lines,regardless of whether they are used as male parent or female parent.The SSS line had a great influence on grain dehydration rate.The variance of general combining ability of grain dehydration rate was much smaller than that of special combining ability,and the narrow sense heritability was low,which indicated that non-additive effect was more important in hybrid populations,dominant and epistatic effects played a major role,and the grain dehydration rate was greatly affected by environment.