Nine cycle of mass section to increased oil content in the two synthetics populations of maize (Zea mays L.)

Abstract

The objectives of this study were to estimate changes in oil content and grain yield in the maize populations DS7u and YuSSSu. As estimations were performed at CO and C9 for both populations, it was possible to observe changes occurring following long-term mass selection for high oil content. The synthetic population DS7u was developed by recombination of 29 inbreeds of Yugoslav, Canadian and US origin. The synthetic population YuSSSu is an Iowa Stiff Stalk Synthetic - BSS(R)C5. The following statistical and genetic parameters were analyzed: means, frequency distribution, components of genetic variance and heritability. Progenies were derived according to the North Carolina Design II. Results were indicated that nine cycles of selection led to statistically significant increase in oil content and statistically significant decrease for grain yield in both populations. Estimates of additive and dominance variances for grain oil content were highly significant in C0 and C9 of the population DS7u. Dominance variance showed significance in the initial cycle of the population YuSSSu, but it disappeared in the course of nine cycles of mass selection. Additive and dominance variances for grain yield were highly significant in both initial populations. Loss of significance did not result from selection, while the proportion of dominance vs. additive variance became greater. High narrow-sense heritability was detected for grain yield and oil content in the initial cycles of both populations. Mass selection resulted in increased heritability for oil content in the DS7u population.

Cilj ovog istraživanja je bio da se utvrde promene u sadržaju ulja i prinosu zrna u populacijama kukuruza DS7u i YuSSSu. Pošto su procene parametara rađene za CO i C9 za obe populacije, moguće je pratiti promene tokom dugoročne masovne selekcije za visok sadržaj ulja. Sintetička populacija DS7u dobijena je rekombinacijom 29 inbred linija jugoslavenskog, kanadskog i američkog porekla. Sintetička populacija YuSSSu je Iowa Stiff Stalk Synthetic -BSSSC5- Familije su dobijene prema North Carolina Design II modelu. Rezultati su pokazali daje 9 ciklusa selekcije dovelo do statistički značajnog povećanja sadržaja ulja i statistički značajnog smanjenja prinosa zrna u obe populacije. Aditivna i dominantna varijansa za sadržaj ulja su visoko značajne u CO i C9 populacije DS7u. Dominantna varijansa je značajna u početnom ciklusu populacije YuSSSu, ali je ova značajnost nestala posle devet ciklusa masovne selekcije. Aditivna i dominantna varijansa za prinos zrna su visoko značajne u obe početne populacije. Gubitak značajnosti nije nastao usled selekcije, dok se odnos dominantne prema aditivnoj varijansi povećao. Visoka heritabilnost u užem smislu dobijena je za prinos zrna i sadržaj ulja u početnom ciklusu obe populacije. Masovna selekcija dovela je do povećanja heritabilnosti za sadržaj ulja u populaciji DS7u.