Modelling the genetic basis of response curves underlying genotype x environment interaction

Abstract

To increase tolerance to abiotic stresses in breeding programmes, typically families and collections of genotypes are evaluated in series of trials (environments) representing different levels of stress. The statistical analysis of the data from such trials concentrates on modelling the phenotypic behaviour of the genotypes across the set of environments. This phenotypic behaviour can be modelled in the form of genotype-specific linear and non-linear response curves in relation to environmental characterizations. Non-parallelism of the response curves indicates genotype × environment interaction. Identification of the genetic basis of the parameters determining the response curves will help in the development of breeding programmes for improving abiotic stress tolerance and understanding genotype × environment interaction. In this paper we present two strategies for locating quantitative trait loci for response-curve parameters and estimation of their allele effects. The procedures are illustrated by an application to drought stress in maize