Towards the use of modelling in genetic improvement: example of peach fruit quality
Résumé
Improving fruit quality raises major difficulties. To overcome these difficulties, an interdisciplinary approach has been developed which consists in forwards and backwards between modelling, ecophysiological analysis and quantitative genetics. This approach has been applied to studies of fruit quality in peach. A population of 140 genotypes derived from a clone of wild peach (Prunus davidiana) by three generations of crosses with commercial cultivars of nectarine (Prunus persica) was studied and genotyped with 8O markers. The ecophysiological model predicts fruit and stone dry and fresh masses and total sugar concentration in relation to environmental conditions. Quantitative Trait Loci (QTL) were detected for all the model parameters and in many cases they were common to both years of experimentation. Co-locations between QTLs for quality traits and QTLs for parameters were observed. The QTL results were used to predict, for any genotype of the populations studied, the values of each parameter which were integrated into the ecophysiological model. This approach could provide a framework for understanding physiological and biological phenomena via the dissection of the quality traits into basic processes. The integration of genetic information into the ecophysiological model may be used for practical purposes, such as predicting the genotypic variations of a plant response to environmental conditions. It may also help to solve genotype and environment (GxE) interactions and to predict the behaviour of plants from the population with any combination of alleles under any climatic scenario.