Premium
A Comparison of Replicated S 1 per se vs. Reciprocal Full‐Sib Index Selection in Corn. I. Indirect Response to Population Densities 1
Author(s) -
West D. R.,
Compton W. A.,
Thomas M. A.
Publication year - 1980
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/cropsci1980.0011183x002000010009x
Subject(s) - biology , selection (genetic algorithm) , population , demography , sociology , computer science , artificial intelligence
Two cycles of S 1 per se selection have been completed in each of three corn ( Zea mays L.) populations: Nebraska B Synthetic (NBS), Nebraska Stiff Stalk Synthetic (NSS), and improved Nebraska Krug variety (NKS). In addition, two cycles of reciprocal full‐sib recurrent selection (RFS) have been completed between NBS and NSS and between NBS and NKS. Each selection scheme was replicated three times. Selection was based on an index (resulting in a calculated value of yield on standing plants) and on yield trials generally grown at 51,666 plants/ha. Response at 68,888 and 17,222 plants/ha (called here indirect density response) is reported in this study. Each replicate of each selection procedure was grown as an S 1 , random mating (RM), or variety cross population. Index values of cycle 2 (C 2 .) were increased 20% or more over C 0 in tests of bulked S 1 populations selected by S 1 per se performance while response to RFS selection varied from an increase of 9% in C 2 of NKS to a negative response of −10% in NBS. Significant selection ✕ plant populaion density effects were found only in the random mating test of the NKS population. Response to S 1 per se selection was significantly greater than response to RFS selection in the NBS random mating population, but response to the two methods did not differ in NSS or NKS grown as random mating populations. Index means of variety crosses of C 2 were approximately 12% above C 0 variety crosses and there were no differences between selection methods. The evaluation of selection response indicated that in the early cycles of selection, response to selection at one plant density will be unchanged when selection products are grown at other plant densities. Response to S 1 per se selection was greater than RFS selection response in bulk S 1 and RM evaluations, but the RFS and S 1 per se methods resulted in equal improvement of variety cross performance.