Polymorphism of SSR markers in maize hybrids

Genetička divergentnost 97 savremenih hibrida kukuruza, koji se gaje u Srbiji u poslednjih nekoliko godina, procenjena je pomoću 12 jednostavnih ponavljajućih sekvenci ili SSR (eng. Simple Sequence Repeats) markera. Ukupno je utvrđeno 94 alela, sa prosečno 7,8 alela po lokusu, u rasponu od 5 do 17 alela. Više od 50% su bili retki aleli sa frekvencijom manjom od 5%. PIC (eng. Polymorphism Information Content) vrednosti kretale su se od 0,42, za umc1792, do 0,81, za dupssr10, sa prosekom od 0,64. Ritlandove vrednosti srodnosti varirale su od 0,787 do -0,129. Minimalan broj markera dovoljan da se utvrdi razlika između hibrida sa jedinstvenim genotipom bio je osam. Analiza glavnih koordinata razdvojila je ranostasnu i kasnostanu grupu hibrida kukuruza, iako stepen diferencijacije između grupa nije bio velik (Fst = 0,4%). Tri markera, bnlg1556, umc1075 i dupssr10, najviše su doprineli razdvajanju ranih i kasnih genotipova, pri čemu je razdvajanje za prva dva markera bilo statistički značajno.The aim of this study was to assess genetic diversity among 97 modern maize hybrids that represent maize varieties grown in Serbia during the last several years. To this end, 12 simple sequence repeat (SSR) markers were used for fingerprinting. In total, 94 alleles were detected, with the average number of 7.8 alleles per locus, ranging from 5 to 17. More than 50% were rare alleles with frequency less than 5%. The polymorphic information content ranged from 0.42, for umc1792, to 0.81, for dupssr10, with an average of 0.64. Pairwise relatedness Ritland‟s values varied from 0.787 to -0.129. The minimum number of markers sufficient to differentiate hybrids with unique genotypes was eight. A principal coordinate analysis distinguished early and late maturing groups of hybrids, although the observed differentiation between groups was rather low (Fst = 0.4%). Three markers, namely bnlg1556, umc1075 and dupssr10, contributed most to the discrimination between early and late genotypes, the first two significantly