Genetic Diversity of F₁ Hybrids Population of Different Broccoli Varieties

Taking 144 F₁ populations of 7 different broccoli varieties as test materials, SSR molecular marker method was adopted to research genetic diversity and variation of F₁ generation of broccoli crosses, in order to provide reference for breeding of new broccoli varieties.The results showed that a total of 27 alleles were detected by 3 pairs of SSR primers in the tested materials, and the average number of alleles was 9 per SSR marker; the average value of the number of effective alleles（N_e）,Shannon′s diversity index（I）,observed heterozygosity（H_o）,expected heterozygosity（H_e）,Nei′s expected heterozygosity and average heterozygosity were 2.536 4,1.129 7,0.768 0,0.598 7,0.598 4 and 0.454 8,respectively; the genetic differentiation coefficient indicated that genetic variation mainly existed in different F₁ progeny populations（74.07%）;the analysis of molecular variance showed that the genetic variation of broccoli F₁ generation mainly came from within its population（82.12%）,which was consistent with the result of genetic differentiation coefficient; the results of UPGMA cluster analysis showed that 7 different broccoli varieties could be clustered into 3 groups at the genetic distance of 0.2;F₁ progenies of the same broccoli variety or broccoli varieties with similar genetic distance could be clustered together by PCA analysis, which was basically consistent with the results of population genetic structure analysis, and F₁ offspring of different broccoli varieties had the phenomenon of cross overlap, which also existed in extensive gene exchange among them.