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Genetic divergence in two tropical maize composites after four cycles of reciprocal recurrent selection
Author(s) -
Kolawole Adesike O.,
Menkir Abebe,
Gedil Melaku,
Blay Essie,
Ofori Kwadwo,
Kling Jennifer G.
Publication year - 2017
Publication title -
plant breeding
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.583
H-Index - 71
eISSN - 1439-0523
pISSN - 0179-9541
DOI - 10.1111/pbr.12439
Subject(s) - biology , genetic diversity , selection (genetic algorithm) , linkage disequilibrium , genetic divergence , population , allele , reciprocal , genetics , haplotype , demography , linguistics , philosophy , artificial intelligence , sociology , computer science , gene
Two tropical maize composites were subjected to four cycles of reciprocal recurrent selection to develop divergent inbred lines with good combining ability. This study was conducted to examine the extent of genetic diversity, changes in allele composition and genetic structure, of 100 randomly selected S 1 lines each from the original (C 0 ) and advanced (C 4 ) selection cycles of TZL COMP 3 and TZL COMP 4, genotyped using single nucleotide polymorphism ( SNP ) markers. Results revealed that the proportion of alleles at both low and high frequencies decreased from C 0 to C 4 , whereas those at intermediate frequencies increased at C 4 in the two composites. More unique and other alleles were lost at C 4 in TZL COMP 3 relative to those in TZL COMP 4. The changes in different measures of genetic diversity were either small or negligible with selection in the two composites. The proportion of markers departing from Hardy–Weinberg equilibrium ( HWE ) decreased with selection, whereas the total number of pairs of markers in linkage disequilibrium increased with selection in the two composites. Examination of changes in population structures using a model‐based approach as well as cluster and multivariate analyses found a high degree of concordance in stratifying the 400 S 1 lines into four non‐overlapping groups corresponding to the two selection cycles each within the reciprocal composites. The observed molecular‐based divergence between cycles within the same composite and the clear differentiation between the complementary composites highlight the importance of reciprocal recurrent selection for preserving genetic diversity for long‐term selection. This increases the potential of the advanced selection cycles to sustain genetic gain in productivity of hybrids adapted to the savannas in West and Central Africa.