The appearance of blotch/ tiger stripe on chickpea seeds is a genotype-specific seed marking which, although not considered a defect during seed inspection, is often rejected based on consumer trait preferences. This study aimed to investigate the expression of blotch/tiger stripe, thousand grain weight (TGW) and days to podding in Australian desi-type chickpea. A single seed-descent mapping population of 242 F derived progeny lines was selected from a controlled cross of two homozygous parent genotypes, PBA Slasher x Sonali. An independent set of nineteen cultivars/advanced genotypes was used to validate the results of the mapping population. Field trials were carried out over two years in Narrabri, north-western NSW, Australia. We phenotypically analysed the mapping population and validation set of cultivars/genotypes for the proportion of blotch/tiger stripe and then carried out composite interval mapping QTL analysis to identify genetic loci linked with the traits of interest. Significant markers that were identified in the mapping population were validated on the additional nineteen cultivars/genotypes. Significant phenotypic variation in the expression of blotch/tiger stripe was observed (P<0.001) and blotch/tiger stripe was found to be highly heritable (H = 0.98). TGW of seeds marked with blotch/tiger stripe (200.9 g) was significantly lower than that of unmarked seeds (208.2 g) (P<0.001). Five Quantitative Trait Loci (QTL) relating to blotch/tiger stripe were identified consistently across the two seasons. A major QTL linked with the reduced expression of blotch/tiger stripe was identified at QTL 1 which reduced the expression of the trait by up to 9.92%. KASP (Kompetitive Allele-specific PCR) markers were developed for this locus and validated in the set of nineteen cultivars/genotypes in which 13–19% of phenotypic variation was accounted for. Significant phenotypic variation in the expression of blotch/tiger stripe was observed and the trait was found to be highly heritable. Five QTL relating to blotch/tiger stripe were identified and the region at QTL 1 was identified as a candidate for fine mapping to determine the genetic variant which is responsible for the trait. KASP markers developed in this study will be of value to breeders, allowing marker assisted selection (MAS) to screen for this trait in the absence of phenotypic symptoms. This study will benefit the chickpea industry by increasing industry awareness of the marking and reducing the prevalence of blotch/tiger stripe in breeding germplasm, therefore reducing seed rejection and protecting grower profits.

中文翻译：

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澳大利亚 desi 型鹰嘴豆斑纹/虎纹的表型和基因型分析

鹰嘴豆种子上出现的斑点/虎纹是一种基因型特异性种子标记，尽管在种子检验过程中不被视为缺陷，但通常会根据消费者性状偏好而被拒绝。本研究旨在研究澳大利亚 desi 型鹰嘴豆中斑点/虎纹、千粒重 (TGW) 和结荚天数的表达。从两个纯合亲本基因型 PBA Slasher x Sonali 的受控杂交中选择 242 F 衍生后代系的单一种子下降作图群体。使用一组独立的十九个品种/高级基因型来验证绘制群体的结果。现场试验在澳大利亚新南威尔士州西北部的纳拉布里进行了两年多。我们对作图群体和品种/基因型的斑点/虎纹比例的验证集进行了表型分析，然后进行复合区间作图 QTL 分析，以识别与感兴趣的性状相关的遗传位点。在绘图群体中鉴定出的重要标记在另外 19 个品种/基因型上进行了验证。观察到斑点/虎纹表达的显着表型变异（P<0.001），并且发现斑点/虎纹具有高度遗传性（H = 0.98）。带有斑点/虎纹的种子的TGW（200.9 g）显着低于未标记的种子（208.2 g）（P<0.001）。在两个季节中一致鉴定出与斑点/虎纹相关的五个数量性状基因座（QTL）。在 QTL 1 处鉴定出与斑点/虎纹表达减少相关的主要 QTL，该 QTL 使该性状的表达减少高达 9.92%。针对该位点开发了 KASP（竞争性等位基因特异性 PCR）标记，并在 19 个品种/基因型组中进行了验证，其中 13-19% 的表型变异被考虑在内。观察到斑点/虎纹表达的显着表型变异，并且发现该性状具有高度遗传性。鉴定了与斑点/虎纹相关的五个 QTL，并将 QTL 1 的区域鉴定为精细定位的候选区域，以确定导致该性状的遗传变异。本研究中开发的 KASP 标记对育种者有价值，允许标记辅助选择 (MAS) 在没有表型症状的情况下筛选该性状。这项研究将提高行业对标记的认识并减少育种种质中斑点/虎纹的流行，从而减少种子排斥并保护种植者利润，从而使鹰嘴豆行业受益。