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Probability of Net Gain of Favorable Alleles for Improving an Elite Single Cross
Author(s) -
Metz Grant
Publication year - 1994
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/cropsci1994.0011183x003400030013x
Subject(s) - allele , biology , epistasis , genetics , dominance (genetics) , zea mays , gene , agronomy
Choice of donor to improve an elite single cross maize ( Zea maize L.) hybrid is critical to the success of a breeding program. Theory has been developed to identify lines (I w ) possessing favorable dominant alleles not present in the elite single cross (I 1 × I 2 ). This paper evaluates the probability of I w to improve I 1 × I 2 . Assuming complete dominance, μG' estimates the relative number of loci with favorable alleles in I w but not in I 1 or I 2 . The estimates μD' and μF' are the relative number of loci with favorable alleles in I 1 or I 2 , respectively, but not in I w . Thus, the probability of a net gain of favorable alleles (PNG g ) from I w = max[μG'/(μG' + μ μG'/(μG' + μF')], which estimates the relative number of loci where favorable alleles can be gained as a proportion of the relative number of loci where favorable alleles ca be either gained or lost. The PNG g can be estimated from phenotypic values of I 1 × I w , I 2 × I w , I 1 × I 2 , I 1 , and I 2 . I w per se need not be evaluated. If partial dominance and/or complementary epistasis is prevalent, μE' and μC' estimate additional loci where favorable alleles could be gained from I w to improve I 1 and I 2 , respectively, while μD', μF', and μB' estimate additional loci where favoralbe alleles could be lost from I 1 , I 2 , or both I 1 and I 2 , respectively. Thus, the probability of a net gain of favorable alleles (PNG ccg ) from I w = max[(μE + μG)'/(μB + μD + μE + μG)',(μC + μG)'/(μB + μ + μF + μG)']. In this case, I w needs to be evaluated. The statistics PNG g and PNG ccg can be used to estimate the genetic probability to success of a donor (I w ) to improve an elite hybrid.