| In this experiment,by the results of phenotypic clustering analysis and SSR molecular marker clustering analysis of 60 pop maize selfing lines with large genetic differences,14 selfing lines with distant genetic relationship were selected.On this basis,hybridized combinations(9female parents and 5 male parents)were designed and prepared according to NCⅡ imcomplete diallel cross.The obtained F1 generation and its parents were planted in the experimental field,and their main characters were investigated and statistically analyzed.The results are as follows :(1)Phenotypic characters of 60 selfing lines are analyzed by clustering analysis,60 selfing lines can be divided into 4 major groups at the similarity coefficient of 32.08,the first group includes 22 selfing lines mainly sourced from excellent lines.The second group includes 7 selfing lines mainly sourced from foreign varieties,the third group includes 29 selfing lines mainly sourced from variation varieties,the fourth group includes 2 selfing lines mainly sourced from native varieties.(2)SSR molecular marker clustering analysis was performed on 60 selfing lines.and the 60 selfing lines can be divided into 5 major groups under the genetic coefficient of 0.82.The first group includes 4 selfing lines,the second group includes 44 selfing lines,the third group includes2 selfing lines,the fourth group includes 3 selfing lines,and the fifth group includes 7 selfing lines.(3)It is showed that F1 generation is generally superior in heterosis according to the statistical analysis of 18 characters of 45 hybridized combinations.Among the researched characters,the quantity of positive mid-parent heterosis and heterobeltiosis is greater than that of negative mid-parent heterosis and heterobeltiosis.M1×F1,M1×F2,M2×F5,M7×F4,M1×F5,M6×F5 and M3×F2 have strong advantages in terms of popping rate.M1×F1,M1×F2,M6×F5,M8×F3,M1×F3,M2×F1 and M1×F4have strong advantages in terms of expansion multiple.M1×F1 and M1×F2 have strong advantages in popping rate and expansion multiple.(4)According to the analysis of general combining ability of parent selfing line and the specific combining ability of hybridized combination,the selfing lines of the five good parents F2,F3,M1,M3 and M9 usually have positive general combining ability,so they can be used as the excellent selfing lines in the breeding of excellent popcorn varieties.M6×F5,M5×F2,M2×F5,M1×F1,M7×F4,M7×F3,M1×F2 and M9×F5 have higher and postive specific combining ability of expansion multiple and popping rate,and they are excellent hybridized combinations.(5)In the correlation analysis,the characters with greater correlation between main characters and popping rate are as follows : expansion multiple > ear row number > axis diameter >stem diameter > ear diameter.the characters with greater correlation between main characters and expansion multiple are as follows : popping rate > stem diameter > starch content > ear length >100-grain weight.(6)In the path analysis,the main characters have greater direct effects on popping rate are as follows : grain yield > ear length > expansion multiple > ear row number > ear diameter.The main characters have greater indirect effects on popping rate are as follows : ear diameter > grain yield > axis diameter > ear length > ear weight.(7)The order of broad sense heritability is as follows : expansion multiple > popping rate >protein content > grain yield > plant height > ear height > barren tip length > ear weight > grain number per row > ear length > axis weight > stem diameter > axis diameter > ear row number >fat content > starch content > 100-grain weight > ear diameter.The order of narrow sense heritability is as follows : popping rate > expansion multiple > axis diameter > starch content >fat content > plant height > ear height > protein content > grain yield > stem diameter > ear row number> ear diameter > 100-grain weight > axis weight > grain number per row > barren tip length > ear length > ear weight.It can be selected in early era if broad sense and narrow sense heritability are both high,but if not,it is easy to influence with environment,so it is better to select in late era.(8)According to the quadratic polynomial regression analysis method,when the stem diameter is 3.85 cm,the ear diameter is 3.80 cm,the era row number is 20,the axis diameter is2.40 cm,and the expansion multiple is 29.55,the theoretical maximum value of the popping rate is 1.30.(9)The principal component analysis is used to comprehensively analyze the 45 groups of hybridized combinations.These 11 main characters of popcorn are reduced to 5 principal components.The combination of M5×F3 performs better in the first principal component,the combination of M2×F2 performs better in the second principal component,the combination of M8×F2 performs better in the third principal component,the combination of M9×F2 performs better in the fourth principal component.The comprehensive performance of the combination of M9×F2 and the combination of M1×F1 are better. |
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