## Abstract

Theory and methods for identifying populations (P_{y}) with the highest frequency of favorable dominant alleles not present in an elite single cross (I_{1}× I_{2}) have been developed recently. During selection, new favorable alleles can be transferred from P_{y}to either I_{1} or I_{2} only at the risk of losing favorable alleles already present in the single cross. A "net improvement" (NI) statistic, which estimates the relative number of favorable alleles that can be gained from P_{y}minus the relative number of favorable alleles that can be lost from I_{1} or I_{2}, is presented. NI is calculated as maximum [(I_{1}×P_{y}-I_{1}×I_{2})/2,(I_{2}×P_{y}-I_{1}×I_{2})/2]. Because I_{1} × I_{2} is constant in an experiment, the method reduces to choosing P_{y}populations with the best mean performance in combination with either I_{1} or I_{2}. For a set of maize (Zea mays L.) grain yield data, NI was highly correlated to three other statistics proposed for choosing populations, namely: (1) minimally biased estimate (l {Mathematical expression}μ′) of the relative number of favorable dominant alleles present in P_{y}but not in I_{1} and I_{2}; (2) minimum upper bound on l {Mathematical expression}μ; and (3) predicted performance of the three-way cross [P_{y}(I_{1}× I_{2})]. While l {Mathematical expression}μ′ estimates potential improvement likely to be achieved only through long-term recurrent selection, NI is probably a better predictor of short-term improvement in single-cross performance.

Original language | English (US) |
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Pages (from-to) | 349-352 |

Number of pages | 4 |

Journal | Theoretical and Applied Genetics |

Volume | 80 |

Issue number | 3 |

DOIs | |

State | Published - Sep 1 1990 |

## Keywords

- Favorable alleles
- Populations
- Zea mays L