engleski

Changes of agronomic traits and SSR allele frequencies in the M3S maize population after three cycles of recurrent selection

M3S maize population was developed by intercrossing 12 domestic inbred lines showing good combining ability with both BSSS and Lancaster testers. The population has been subjected to three cycles of recurrent selection to improve grain yield and standability. In the first two cycles selfed progeny selection was used and in the third cycle two selection methods, S1 and full-sib (FS), were conducted separately. Resulting populations were designated as C0, C1, C2, C3-S1 and C3-FS. The objectives of this study were: 1) to evaluate changes in population means for grain yield and stalk rot incidence due to recurrent selection, 2) to compare effectiveness of S1 and FS method, performed separately in the third cycle of selection, in improving population performance and 3) to examine the effect of selection on allele frequency changes in the population. The five cycle populations were evaluated in three growing seasons in natural conditions (N) as well as under artificial inoculation with Colletotrichum graminicola (CG) fungi. Changes in allele frequencies in the population were monitored based on analysis of 32 individuals from C0, C3S1 and C3FS at 37 SSR loci. In N, grain yield increased 10% in the C2 compared to C0. After the third cycle of selection no further improvement of grain yield (C3-FS) or a decrease of grain yield (C3-S1) was observed. In CG grain yield was improved only in C3-FS. A decrease of stalk rot incidence was observed in improved populations as compared to C0 for both N and CG. The FS method was more efficient than S1 method in improving stalk rot resistance. Neutrality test revealed 30% loci in C3-S1 and 40% loci in C3-FS with significant changes of allele frequencies after three cycles of recurrent selection.

maize

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