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Five Cycles of Replicated S 1 vs. Reciprocal Full‐Sib Index Selection in Maize
Author(s) -
Odhiambo M. O.,
Compton W. A.
Publication year - 1989
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1989.0011183x002900020017x
Subject(s) - biology , selection (genetic algorithm) , population , index selection , inbred strain , replicate , statistics , mathematics , genetics , demography , gene , artificial intelligence , sociology , computer science
Five cycles of S 1 per se (S 1 ) and reciprocal full‐sib (RFS) selection were compared for the improvement of three maize ( zea mays L.) populations and two population crosses. The replicated structure of the selection experiments allowed direct comparisons of selection methods together with measures of genetic drift. The selection criterion used was a multiplicative index involving yield, moisture, upright plants, and undropped ears and therefore the experiment measures the value of this type of index in selection studies. Populations and population crosses evaluated were Nebraska B. Synthetic (NBS), Nebraska Stiff Stalk Synthetic (NSS), Nebraska Krug open pollinated variety (NKS), NBS ✕ NSS, and NBS ✕ NKS. Improvement was measured in random mated, bulked inbred (S 1 ) populations, and the population crosses. Both selection procedures were performed in three replicates. The entries for the evaluation study were derived from Cycle 0 and recombined replicate populations from Cycles 3 and 5. The evaluation trials were grown in 1985 and 1986 at Lincoln, NE. The S 1 selection increased index values in the bulked inbred populations by 5.8% per cycle when averaged over populations. The RFS selection increased index values of inbred populations by 3.4% per cycle. Both methods were equally effective in improving index values of the random mated populations with average responses of 2.0% for S 1 and 1.8% for RFS selection per cycle. The average index response in the population crosses was 3.6 and 2.9% per cycle for RFS and S 1 selection, respectively. Genetic drift was observed to cause significant differences among the replicate populations for index and its components.