The relationship between parental genetic or phenotypic divergence and progeny variation in the maize nested association mapping population

Abstract

Appropriate selection of parents for the development of mapping populations is pivotal to maximizing the power of quantitative trait loci detection. Trait genotypic variation within a family is indicative of the family's informativeness for genetic studies. Accurate prediction of the most useful parental combinations within a species would help guide quantitative genetics studies. We tested the reliability of genotypic and phenotypic distance estimators between pairs of maize inbred lines to predict genotypic variation for quantitative traits within families derived from biparental crosses. We developed 25 families composed of B200 random recombinant inbred lines each from crosses between a common reference parent inbred, B73, and 25 diverse maize inbreds. Parents and families were evaluated for 19 quantitative traits across up to 11 environments. Genetic distances (GDs) among parents were estimated with 44 simple sequence repeat and 2303 single-nucleotide polymorphism markers. GDs among parents had no predictive value for progeny variation, which is most likely due to the choice of neutral markers. In contrast, we observed for about half of the traits measured a positive correlation between phenotypic parental distances and within-family genetic variance estimates. Consequently, the choice of promising segregating populations can be based on selecting phenotypically diverse parents. These results are congruent with models of genetic architecture that posit numerous genes affecting quantitative traits, each segregating for allelic series, with dispersal of allelic effects across diverse genetic material. This architecture, common to many quantitative traits in maize, limits the predictive value of parental genotypic or phenotypic values on progeny variance.

Combining ability, heterosis, genetic distance and their intercorrelations for waterlogging tolerance traits in chrysanthemum

“…Wegary et al (2013) also reported that morphological distances were less important than molecular marker-based genetic distances for predicting the F 1 performance of heterosis and SCA effects for grain traits. Nevertheless, PD was a better predictor of gene variance than GD across a 26 maize bi-parent group for 19 traits (Hung et al 2012). …”

Hallauer’s Tusón: a decade of selection for tropical-to-temperate phenological adaptation in maize

“…Among the sample of families from across 10 generations, averaged across nine environments, the timing from planting to silking and anthesis spanned 37 and 27 days, respectively; PLHs ranged from 162 to 267 cm, and ERHs ranged from 73 to 182 cm. The range and magnitude of genotypic variation found here in Hallauer's Tusón exceeded or was comparable to that of the diverse multi-parent NAM population (Buckler et al, 2009;Hung et al, 2012a). The NAM population was designed to maximize the sampling of molecular diversity and has been used to identify numerous loci associated with variation in the aforementioned traits.…”

ZmCCT and the genetic basis of day-length adaptation underlying the postdomestication spread of maize

“…The total number of inbred lines evaluated in field experiments was 5,481. Details of experimental design and phenotype data analysis are provided in the work of Hung et al (38) and in SI Appendix, SI Materials and Methods. Each NAM and IBM line was genotyped with a common set of 1,106 SNP markers chosen to have high informativeness in these crosses (14).…”

“…The maize NAM population was created by crossing 25 diverse inbred lines to the common reference parent B73 and deriving 200 RILs from each cross to form 5,000 mapping lines (14). The NAM population was evaluated in 11 environments, including eight environments with mean day lengths greater than 13 h during the growing season (long-day length environments) and three environments with mean day lengths less than 13 h (short-day length environments) (38). A sample of 200 intermated B73 × Mo17 (IBM) RILs (39) and a panel of 281 lines encompassing much of the global diversity of public maize inbreds ("maize association panel") (32) were also included alongside the NAM lines in field evaluations.…”