Complex Relationships among Water Use Efficiency‐Related Traits, Yield, and Maturity in Tomato Lines Subjected to Deficit Irrigation in the Field

Abstract

Cultivated tomato (Solanum lycopersicum L.) is susceptible to abiotic stresses, including water stress. In contrast, a wild tomato relative, S. habrochaites S. Knapp & D.M. Spooner, is highly tolerant to abiotic stresses. Previously, we used a set of 18 sub‐near‐isogenic tomato lines (sub‐NILs) containing chromosome 9 introgressions from S. habrochaites to investigate the genetic basis of tolerance to rapid‐onset water stress imposed by root chilling. In the present study, this same set of 18 sub‐NILs was subjected to slow‐onset water stress imposed by deficit irrigation in field experiments conducted for 2 yr. Trait data were analyzed with principal component analysis, ANOVA, and MANOVA to investigate the underlying relationships among proxy traits for water‐use efficiency (WUE) including carbon isotope discrimination (Δ13C) and specific leaf area (SLA) with horticultural traits including maturity and yield. The majority of total phenotypic variation among the sub‐NILs was accounted for by Δ13C and SLA, with minor contribution from the horticultural traits. While many trait QTL were coincident or overlapping, our analyses suggest that the genes controlling QTL for Δ13C and SLA in this chromosome 9 region are distinct from each other and also from genes controlling maturity and yield. This introgressed region contains potentially valuable wild alleles for breeding cultivated tomatoes with improved WUE while selecting for yield maintenance.

Genomic Designing for Climate-Smart Tomato

“…They identified no less than 90 seed-quality QTLs under stress conditions. Physiological parameters under WD and nitrogendeficiency conditions were mapped in sub-NILs (Arms et al 2016) and 130 F10 RILs (Asins et al 2017) populations, respectively. Metabolite variation in tomato seeds under SS was studied by Rosental et al (2016) and several QTLs were identified in 72 ILs derived from the introgression of chromosome fragments of S. pennellii LA716 into the domesticated tomato cultivar M82.…”

Fine mapping of QTL for water use efficiency‐related traits on chromosome 9 of Solanum habrochaites in the field

“…Arms et al. (2016) found a low positive correlation between ∆ 13 C and yield traits (RYLD and TYLD) in tomato chromosome 9 sub‐NILs derived from S. habrochaites , indicating a negative correlation with WUE. In the present study, correlations between yield and ∆ 13 C were environmentally dependent.…”