Genetic variability and correlation analysis for grain yield of a narrow base synthetic maize population NSA15

Abstract

S1 progenies of a narrow base maize population NSA15 unrelated to other heterotic sources, derived from a cross of NS15 x NS61 inbred lines, were tested simultaneously with two unrelated inbred-testers: NS732 (ID genetic background) and NS27 (BSSS background). Forty pairs of each HS progenies were made in such a manner that every pair has female parent (S1 line) in common. The families were separately randomized and planted in two trials, using incomplete block design, in two sets each with two replications per set and 20 HS families within a set. In each set, four hybrid checks, which represent a combination of tester lines and component lines of the populations, were planted. The trials were carried out during 2008 (at four locations) and 2009 (at three locations). The standard crop management practices were applied. Higher average yield in most combinations of S1 families x tester were obtained with NS27 line. Approximately 50% of families tested with both testers achieved grain yield higher than average value of the corresponding checks. Heritability for grain yield of HS-1 progeny group (NS732) was significant (h2=0.519±0.228), whereas HS-2 progeny group (NS27) had lower and insignificant heritability (h2=0.337±0.231). At the same time, genetic correlation between two groups of HS progenies for grain yield was also insignificant (rg=0.309±0.253). High values of standard errors for heritability and genetic correlation were mainly caused by drift due to random concentration of more productive genotypes in the set II of the HS-2 trial. The results for grain yield indicated that NS27 inbred-tester is of a greater value for further breeding programme with the population NSA15.

S1 potomstva populacije uže genetičke osnove NSA15 nastale ukrštanjem inbred linija NS15 x NS61, testirana su istovremeno sa dva nesrodna inbred-testera: NS732 (ID genetičke osnove) i NS27 (BSSS osnove). Proizvedeno je po 40 parova HS potomstava, tako da svaki par ima zajedničku majčinsku komponentu (S1 liniju). Porodice su posebno randomizirane i zasejane u dva nezavisna ogleda, po modelu nepotpunog blok dizajna, svaki u dva seta, sa dva ponavljanja u okviru seta i 20 HS familija u setu. Ogledi su izvedeni tokom 2008. (četiri lokaliteta) i 2009. (tri lokaliteta). Primenjena je standardna tehnologija gajenja. Veći prosečan prinos u većini kombinacija S1 familija x tester ostvaren je sa linijom NS27. Oko 50% testiranih familija sa oba testera ostvarilo je veći prinos zrna od proseka odgovarajućih standarda. Heritabilnost za prinos zrna kod HS-1 potomstava nastalih ukrštanjem sa testerom NS732 bila je signifi kantna (h2=0,519±0,228), dok je kod HS-2 potomstava nastalih ukrštanjem sa testerom NS27 zabeležena niža i nesignifikantna vrednost (h2=0,337±0,231). Genetička korelacija između dve grupe HS potomstava za prinos zrna je bila nesignifi kantna (rg=0,309±0,253). Visoke vrednosti standardnih greški za heritabilnost i genetičku korelaciju uslovljene su najvećim delom driftom nastalim slučajnom koncentracijom rodnijih genotipova u II setu HS-2 ogleda. Na osnovu dobijenih rezultata za prinos zrna, inbred-tester NS27 je pokazao perspektivnije rezultate za budući oplemenjivački program sa populacijom NSA15.