Study On Heterosis And Inheritance Of Popping Characters In Popcorn

In this experiment,16 inbred lines featuring great genetic differences and long genetic distances were selected out of 50 pop maize inbred lines using phenotypic clustering method and SSR molecular marker clustering method.On this basis,hybridized combinations were designed according to the incomplete dillel cross test（incl.9 female parents,and 7 male parents）.Then,F1 generation and parent plants were planted in the field for carrying out test measurement,heterosis analysis,combining ability analysis,path analysis,and quadratic polynomial regression.Results are presented as follows:（1）50 inbred lines fall into five categories at the genetic distance of 0.42.To be specific,the first category is composed of 19 inbred lines,most of which are quality lines introduced from other areas;the second category consists of 22 inbred lines,most of which are quality lines with mutation;the third category includes 7 inbred lines;and the fourth and fifth categories each have 1 inbred line.（2）50 inbred lines clustering analysis is performed.Also,50 inbred lines are divided into five different categories at the genetic distance of 0.89.To be concrete,the first category covers 41 inbred lines;the second category is comprised of 4 inbred lines;the third category owns 3 inbred lines;and the fourth and fifth categories each have 1inbred line.（3）16 inbred lines are selected for carrying out an incomplete dillel cross test in the following year.It is found that F₁ is generally superior in heterosis according to the analysis of data of 18 traits of 63 crossbreeds.Moreover,from the perspective of trait data,the number of positive combinations of heterosis over better of parents and heterosis over mean of parents is much more than the number of negative combinations.Besides,M3×F1,M6×F6,M1×F7,M6×F4,M7×F2 have strong advantages in terms of expansion multiples,while M3×F6,M9×F4,M8×F7,M5×F1,M1×F4 have certain superiority from the angle of the trait of popping rate.（4）Four parents of F5,M4,M6,and M8 with higher combining abilities can be selected as fine parents according to the analyses on the general combining ability of the parental inbred lines and the special combining ability of the cross combination.（5）The magnitude on the correlation with popping rate is:plant height>e kernel rows per ear>ear length>weight per hundred kernels>fat content>protein content>axis diameter>axis weight>kernel numbers per row>ear position>starch content>ear diameter>stem diameter>moisture>bare top length>expansion multiple>axis weight.The magnitude on the correlation with expansion multiples is:axis diameter>stem diameter>ear weight>moisture>ear position>protein content>axis weight>bald top length>weight per hundred kernels>kernel numbers per row>starch content>ear diameter>head progeny row>ear length>plant height>popping rate>fat content.（6）The magnitude on the direct influence of traits on popping rate in path analysis is:ear length>ear weight>plant height>axis weight>ear height>protein content>fat content>axis diameter>weight per hundred kernels>expansion multiples>starch content>bald top length>kernel rows per ear>moisture>stem diameter>axis diameter>kernel numbers per row>weight per hundred kernels.（7）As can be seen from the polynomial,the highest popping rate（0.908）in theory can be obtained when the plant height is 282.54cm;the ear weight is 84.79g;the ear length is 19.4cm;the kernel number per row is 16.94;the axis diameter is 1.42cm;the weight per hundred kernels is 19.97g;the fat content is 5%;and the protein is 11%.