Abstract Upland cotton (Gossypium hirsutum) is the most important fiber crop and an important oilseed crop in the world. Developing drought tolerant cultivars is important to sustainable cotton production in arid and semi-arid regions. However, there is a lack of information on genetic variation for drought tolerance in breeding populations. In this study, a backcross inbred line (BIL) Upland population with germplasm introgression from a more drought-tolerant American Pima cotton (G. barbadense) parent was evaluated in multiple field environments under well-watered (WW) and water-limited (WL) conditions at the flowering stage. Drought at the flowering stage reduced seedcotton yield (SCY), lint yield (LY), boll weight (BW), fiber length (FL), and fiber strength (STR) but increased lint percentage (LP), micronaire (MIC), neps per size, nep per gram, seedcoat nep size, and seed coat fragment count by gram. Significant genetic differences in the BIL population were detected for most agronomic and fiber quality traits and drought susceptibility index (DSI) for these traits. DSI of SCY and LY ranged from 0.01 to 1.5 and 0.1–1.45, respectively, reflecting the tolerance level of the BILs under WL conditions. The broad-sense heritability estimates were moderate for most agronomic traits and moderate to high for most fiber quality traits. Results indicated that highly positive correlation was detected for agronomic and fiber quality traits between WW and WL conditions, with the highest correlations for SCY, LY, UHM, SCY, and MIC. Promising BILs with drought tolerance were identified. This study has provided a line of evidence that field drought tolerance was transferred from the more drought tolerant Pima line to Upland cotton.

中文翻译：

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田间条件下干旱对陆棉回交自交系群体中农艺和纤维品质的影响

摘要 陆地棉（Gossypium hirsutum）是世界上最重要的纤维作物和重要的油料作物。开发耐旱品种对于干旱和半干旱地区的可持续棉花生产非常重要。然而，缺乏育种群体耐旱性遗传变异的信息。在这项研究中，在充足浇水 (WW) 和限水 (WL) 条件下的多个田间环境中评估了回交自交系 (BIL) 高地种群，该种群具有来自更耐旱的美国比马棉 (G. barbadense) 亲本的种质渗入) 开花期的条件。开花期干旱降低了籽棉产量 (SCY)、皮棉产量 (LY)、铃重 (BW)、纤维长度 (FL) 和纤维强度 (STR)，但增加了皮棉百分比 (LP)、马克隆值 (MIC)、棉结每个尺寸，每克棉结，种皮棉结大小和种皮碎片按克计。对于大多数农艺和纤维品质性状以及这些性状的干旱易感性指数 (DSI)，在 BIL 种群中检测到显着的遗传差异。SCY 和 LY 的 DSI 范围分别为 0.01 至 1.5 和 0.1-1.45，反映了 WL 条件下 BIL 的耐受水平。大多数农艺性状的广义遗传力估计为中等，大多数纤维品质性状的广义遗传力估计为中等至高。结果表明，WW和WL条件之间的农艺性状和纤维品质性状呈高度正相关，其中SCY、LY、UHM、SCY和MIC的相关性最高。确定了具有耐旱性的有希望的 BIL。