Fresh water is increasingly limited due to climate change. One way to reduce fresh water use by irrigated agriculture is to breed plants that can produce adequate yields with less water. A wild tomato, Solanum habrochaites, is more water stress tolerant than cultivated tomato, S. lycopersicum L. Our study aimed to fine map quantitative trait loci (QTL) for maturity, yield, and water use efficiency (WUE)-related traits (shoot dry weight and carbon isotope discrimination, ∆¹³C) on chromosome 9 in S. habrochaites using a set of 21 sub-near isogenic lines (sub-NILs). These sub-NILs and controls were evaluated in field experiments grown under full and reduced irrigation treatments across 2 yr. Genotype × environment interactions were significant, so the data was separated into subsets of environments for further analyses. Significant QTL were detected for 20 trait–environment combinations. All QTL were partially or completely coincident. The presence of the S. habrochaites allele at QTL was associated with later maturity, lower yields, and greater WUE. However, yield and ∆¹³C exhibited no or low correlations with each other, suggesting these traits could be selected for improvement independently during breeding. Two of 21 sub-NILs showed superior performance for WUE and yield compared to controls. These two genotypes may prove useful in breeding programs to improve the WUE of tomato cultivars without negative effects on yield.

中文翻译：

---

田间马铃薯9号染色体水分利用效率相关性状QTL精细定位

由于气候变化，淡水越来越有限。减少灌溉农业淡水使用的一种方法是培育可以用更少的水产生足够产量的植物。野生番茄Solanum habrochaites比栽培番茄S. lycopersicum L 更耐水胁迫。我们的研究旨在精细定位数量性状位点 (QTL) 以了解成熟度、产量和水分利用效率 (WUE) 相关性状（芽干重和碳同位素鉴别，Δ ¹³ C) 在S. habrochaites 9 号染色体上使用一组 21 个亚近等基因系（亚 NIL）。这些亚 NIL 和对照在 2 年的完全和减少灌溉处理下生长的田间试验中进行了评估。基因型×环境相互作用很重要，因此数据被分成环境子集以供进一步分析。检测到 20 个性状-环境组合的显着 QTL。所有 QTL 部分或完全重合。QTL 中S. habrochaites等位基因的存在与晚熟、低产和高 WUE 有关。然而，产量和 ∆ ¹³C 之间没有相关性或相关性很低，表明可以在育种过程中独立选择这些性状进行改良。与对照相比，21 个亚 NIL 中有两个在 WUE 和产量方面表现出优异的性能。这两种基因型可能在育种计划中被证明是有用的，以提高番茄品种的 WUE，而不会对产量产生负面影响。