Whole chromosome analysis of height in wheat

Abstract

The genetical architecture of height in the cross between the wheat varieties Chinese Spring and Cappelle-Desprez is examined using crosses involving the complete set of single chromosome substitution lines of Cappelle-Desprez into Chinese Spring. Seventeen of the 21 chromosome pairs exhibit genetical variation with respect to this character and in addition to additive and dominance effects, epistatic effects of an additive × additive type are shown to be an important component of the variation. The details of the genetical architecture revealed by whole chromosome analysis on the one hand and conventional generation means analysis on the other are very similar. However, the whole chromosome analysis reveals a much greater complexity and in particular shows that the heterosis exhibited in the between the parents is explained by the dispersion of increasing chromosomes between the parents with directional dominance for increasing loci, combined with between chromosome interactions. Estimation of the effects of individual chromosomes is attempted but a satisfactory model is not found. Nevertheless, tentative predictions as to the consequences of new chromosomal combinations are made on the basis of the best fitting model. © 1977, The Genetical Society of Great Britain. All rights reserved.