Table_1_Novel Salinity Tolerance Loci in Chickpea Identified in Glasshouse and Field Environments.XLSX

A better understanding of the genetics of salinity tolerance in chickpea would enable breeding of salt tolerant varieties, offering potential to expand chickpea production to marginal, salinity-affected areas. A Recombinant Inbred Line population was developed using accelerated-Single Seed Descent of progeny from a cross between two chickpea varieties, Rupali (salt-sensitive) and Genesis836 (salt-tolerant). The population was screened for salinity tolerance using high-throughput image-based phenotyping in the glasshouse, in hydroponics, and across 2 years of field trials at Merredin, Western Australia. A genetic map was constructed from 628 unique in-silico DArT and SNP markers, spanning 963.5 cM. Markers linked to two flowering loci identified on linkage groups CaLG03 and CaLG05 were used as cofactors during genetic analysis to remove the confounding effects of flowering on salinity response. Forty-two QTL were linked to growth rate, yield, and yield component traits under both control and saline conditions, and leaf tissue ion accumulation under salt stress. Residuals from regressions fitting best linear unbiased predictions from saline conditions onto best linear unbiased predictions from control conditions provided a measure of salinity tolerance per se, independent of yield potential. Six QTL on CaLG04, CaLG05, and CaLG06 were associated with tolerance per se. In total, 21 QTL mapped to two distinct regions on CaLG04. The first distinct region controlled the number of filled pods, leaf necrosis, seed number, and seed yield specifically under salinity, and co-located with four QTL linked to salt tolerance per se. The second distinct region controlled 100-seed weight and growth-related traits, independent of salinity treatment. Positional cloning of the salinity tolerance-specific loci on CaLG04, CaLG05, and CaLG06 will improve our understanding of the key determinants of salinity tolerance in chickpea.

深入解析鹰嘴豆（chickpea）耐盐性的遗传机制，将有助于培育耐盐品种，从而有望将鹰嘴豆种植拓展至受盐渍化影响的边际土地。本研究通过两个鹰嘴豆品种——盐敏感品种Rupali与耐盐品种Genesis836的杂交后代，采用加速单粒传（accelerated-Single Seed Descent）法构建了重组自交系（Recombinant Inbred Line）群体。该群体通过三种方式开展耐盐性筛选：温室环境下的高通量图像表型分析（high-throughput image-based phenotyping）、水培试验（hydroponics），以及在澳大利亚西部梅里丁（Merredin）开展的两年田间试验。本研究基于628个独特的虚拟DArT（in-silico DArT）与单核苷酸多态性（SNP）标记构建了遗传图谱，总图距达963.5厘摩（cM）。在遗传分析中，将与连锁群（linkage group）CaLG03和CaLG05上两个开花位点连锁的标记作为协变量，以消除开花期对耐盐性响应的混淆效应。共鉴定到42个数量性状位点（Quantitative Trait Locus, 简称QTL），这些位点与对照及盐胁迫条件下的生长速率、产量及产量组分性状，以及盐胁迫下的叶片组织离子积累量相关。将盐胁迫条件下的最佳线性无偏预测（best linear unbiased prediction, 简称BLUP）值对对照条件下的BLUP值进行回归，所得残差可作为耐盐性本身的衡量指标，不受产量潜力的影响。在CaLG04、CaLG05与CaLG06连锁群上共鉴定到6个与耐盐性本身相关的QTL。总计有21个QTL定位在CaLG04连锁群的两个不同区域内：第一个区域特异性调控盐胁迫下的饱满荚果数、叶片坏死程度、籽粒数与籽粒产量，且与4个与耐盐性本身相关的QTL共定位；第二个区域则调控百粒重与生长相关性状，且不受盐胁迫处理的影响。对CaLG04、CaLG05与CaLG06连锁群上的耐盐特异性位点进行图位克隆（positional cloning），将有助于进一步解析鹰嘴豆耐盐性的关键决定因子。