Watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] is an important cucurbit crop cultivated worldwide. In an effort to map WBNV resistance, the current study consisted of two populations derived from a WBNV resistant accession, IIHR-82 belonging to Citrullus lanatus var. citroides (Syn. Citrullus amarus). The first population is a backcross inbred population (BC1F6) of 141 families (Pop I) that was developed by crossing IIHR-82 to an elite cultivar Arka Manik. A resistant family, BIL-53 belonging to Pop I was crossed to IIHR-140 to develop F3 population, consisting of 112 families (Pop II). Each of these populations was evaluated for WBNV incidence for two years under natural epiphytotic conditions. A significant correlation was observed for various resistance traits across years and populations. The frequency distribution graphs of Area Under Disease Progress Curve for WBNV incidence in both the populations exhibited a continuous distribution, indicating that trait is quantitative in nature. A total of 163 markers were mapped for the Pop I which spread onto 15 linkage groups (LGs) spanning a total map length of 3310.17 cM with a mean marker interval of 20.31 cM. The linkage map for the Pop II was constructed with 135 markers spread over 12 linkage groups spanning a total length of 1965.53 cM with an average interval between markers of 14.56 cM.The QTL analysis for WBNV resistance related traits revealed 14 major QTL's for Pop I and 19 for Pop II with a maximum PVE upto 21.20%. Multi-trait QTL regions were observed on LG 3b for Pop I and LG 2, LG 4, LG 7 and LG 8 for Pop II. Importantly, we observed common QTL regions for plant survival on LG 2 and PDI on LG 3 and LG 8 for both the populations. As this is the first attempt to map QTL's for WBNV resistance, the results obtained in the present study may provide a guide for fine mapping multi-trait QTL regions.

中文翻译：

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绘制西瓜对西瓜芽坏死正孢病毒抗性的数量性状基因座 [Citrullus lanatus (Thunb.) Matsum & Nakai]

西瓜 [Citrullus lanatus (Thunb.) Matsum & Nakai] 是世界范围内种植的重要葫芦科作物。为了绘制 WBNV 抗性图，目前的研究由来自 WBNV 抗性种质 IIHR-82 的两个种群组成，属于 Citrullus lanatus var. citroides (Syn. Citrullus amarus)。第一个种群是 141 个家族 (Pop I) 的回交自交种群 (BC1F6)，它是通过将 IIHR-82 与优良品种 Arka Manik 杂交而开发的。属于Pop I的抗性家族BIL-53与IIHR-140杂交形成F3群体，由112个家族（Pop II）组成。在自然附生条件下对这些种群中的每一个进行了两年的 WBNV 发病率评估。观察到不同年份和种群的各种抗性性状的显着相关性。两个群体中WBNV发病率的疾病进展曲线下面积的频率分布图表现出连续分布，表明性状本质上是定量的。Pop I 总共绘制了 163 个标记，这些标记扩展到 15 个连锁群 (LG)，总地图长度为 3310.17 cM，平均标记间隔为 20.31 cM。Pop II 的连锁图谱由分布在 12 个连锁群的 135 个标记构建，总长度为 1965.53 cM，标记之间的平均间隔为 14.56 cM。 WBNV 抗性相关性状的 QTL 分析揭示了 Pop I 和Pop II 19，最高PVE高达21.20%。在流行 I 的 LG 3b 和流行 II 的 LG 2、LG 4、LG 7 和 LG 8 上观察到多性状 QTL 区域。重要的，我们在 LG 2 上观察到植物存活的共同 QTL 区域，在 LG 3 和 LG 8 上观察到两个种群的 PDI。由于这是首次尝试绘制 WBNV 抗性 QTL，因此本研究中获得的结果可为精细绘制多性状 QTL 区域提供指导。