Genotype–environment interactions affecting preflowering physiological and morphological traits of Brassica rapa grown in two watering regimes

• Published in: Journal of experimental botany Vol. 65; no. 2; pp. 697 - 708
• Main Authors: El-Soda, Mohamed, Boer, Martin P, Bagheri, Hedayat, Hanhart, Corrie J, Koornneef, Maarten, Aarts, Mark G. M
• Format: Journal Article
• Language: English
• Published: England Oxford University Press [etc.] 01.02.2014; Oxford University Press
• Subjects: Alleles; arabidopsis; Biomass; Brassica - anatomy & histology; Brassica - genetics; Brassica - growth & development; Brassica - physiology; Brassica rapa; breeding; by-environment interactions; Chromosome Mapping; Chromosomes; Cluster Analysis; correlation; Drought; drought tolerance; Droughts; Environment; evolution; Flowers - anatomy & histology; Flowers - physiology; genetic architecture; genetic variance; genetic variation; Genotype; growth performance; hypocotyls; inbred lines; Inbreeding; leaves; loci; nutrient solutions; Phenotype; Phenotypic plasticity; Phenotypic traits; plant; Plant genetics; plant growth; Plant Stomata - physiology; Population characteristics; qtl analysis; Quantitative trait loci; Quantitative Trait Loci - genetics; Quantitative Trait, Heritable; quantitative traits; Reproducibility of Results; RESEARCH PAPER; root-system architecture; Stomatal conductance; temperature; Water; genotype–environment interaction; stomatal conductance; Brassica rapa; drought; plasticity; root/shoot ratio; Antagonistic fitness effect
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ert434

Plant growth and productivity are greatly affected by drought, which is likely to become more threatening with the predicted global temperature increase. Understanding the genetic architecture of complex quantitative traits and their interaction with water availability may lead to improved crop adaptation to a wide range of environments. Here, the genetic basis of 20 physiological and morphological traits is explored by describing plant performance and growth in a Brassica rapa recombinant inbred line (RIL) population grown on a sandy substrate supplemented with nutrient solution, under control and drought conditions. Altogether, 54 quantitative trait loci (QTL) were identified, of which many colocated in 11 QTL clusters. Seventeen QTL showed significant QTL–environment interaction (Q×E), indicating genetic variation for phenotypic plasticity. Of the measured traits, only hypocotyl length did not show significant genotype–environment interaction (G×E) in both environments in all experiments. Correlation analysis showed that, in the control environment, stomatal conductance was positively correlated with total leaf dry weight (DW) and aboveground DW, whereas in the drought environment, stomatal conductance showed a significant negative correlation with total leaf DW and aboveground DW. This correlation was explained by antagonistic fitness effects in the drought environment, controlled by a QTL cluster on chromosome A7. These results demonstrate that Q×E is an important component of the genetic variance and can play a great role in improving drought tolerance in future breeding programmes.