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This article in CS

  1. Vol. 17 No. 5, p. 754-757
     
    Received: Feb 6, 1976


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doi:10.2135/cropsci1977.0011183X001700050019x

Comparison of Combined Half-sib and S1 Family Selection with Half-sib, S1, and Selection Index Procedures in Maize

  1. C. K. Goulas and
  2. J. H. Lonnquist2

Abstract

Abstract

A combined half-sib (HS) and Sl family evaluation procedure (HS-S1) in a maize (Zea mays L.) population was compared with HS and S1 per se evaluation and with a selection index of the form I = b1Xl + b2X2 where X1 and X2 are grain yields of the HS and S1 families, respectively. The combined HS-S1 evaluation resulted in lower selection differentials than either HS or S1 evaluation. Combined HS-S1 selection in the CO (original population) identified 81, 71, and 77% of the selected families in common with HS, S1 and a selection index, respectively, and 60, 58, and 85% in CI. HS-S1 resulted in selection of genotypes better buffered to environmental differences than either HS or $1 alone. The evidence indicates that HS evaluation results in selection of genotypes with above average population heterotic response and greater than average inbreeding depression while S1 evaluation has the opposite effect. Selection on combined HS-S1 evaluation resulted in genotypes with less than average inbreeding depression and average or better heterotic response. The selection index has a similar effect. Expected gains showed combined HS-S1 with resynthesis using S1 progenies to be equal to or greater than other procedures.

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