Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad, 38040, Pakistan.
Federal Seed Certification and Registration Department, Ministry of National Food Security and Research, Islamabad, 44090, Pakistan.
BMC Plant Biol. 2023 Oct 23;23(1):508. doi: 10.1186/s12870-023-04441-2.
Drought is one of the limiting factors for quality and quantity of cotton lint in tropical and sub-tropical regions. Therefore, development of drought tolerant cotton genotypes have become indispensable. The identification of drought tolerant genotypes is pre-requisite to develop high yielding cultivars suitable for drought affected areas.
Forty upland cotton accessions were selected on the basis of their adaptability and yield. The collected germplasm accessions were evaluated at seedling stage on the basis of morphological, physiological and biochemical parameters. The experiment was conducted under controlled conditions in greenhouse where these genotypes were sown under different levels of drought stress by following factorial under completely randomized design. The data were collected at seedling stages for root and shoot lengths, relative leaf water content, excised leaf water losses, peroxidase content and hydrogen peroxide concentrations in leaf tissues.
The biometrical analysis revealed that germplasm is significantly varied for recorded parameters, likewise interaction of genotypes and water stress was also significantly varied. The cotton germplasm was categorized in eight clusters based on response to water stress. The genotype Cyto-124 exhibited lowest HO content under drought conditions, minimum excised leaf water loss under stress environment was exhibited by genotypes Ali Akber-802 and CEMB-33. Overall, on the basis of morphological and biochemical traits, SL-516 and Cyto-305 were found to be drought tolerant. Genotypes 1852 - 511, Stoneville 15-17 and Delta Pine-55 showed low values for root length, peroxidase activity and higher value for HO contents. On the basis of these finding, these genotypes were declared as drought susceptible.
The categorization of cotton germplasm indicating the differential response of various parameters under the control and drought stress conditions. The recorded parameters particularly relative leaf water contents and biochemical assays could be utilized to screen large number of germplasm of cotton for water deficit conditions. Besides, the drought tolerant genotypes identified in this research can be utilized in cotton breeding programs for the development of improved cultivars.
干旱是热带和亚热带地区棉花纤维质量和数量的限制因素之一。因此，培育耐旱棉花基因型已变得不可或缺。耐旱基因型的鉴定是开发适合干旱地区的高产品种的前提。
根据适应性和产量选择了 40 个陆地棉品种。根据形态学、生理学和生物化学参数，在幼苗期对收集的种质资源进行评价。该实验在温室控制条件下进行，通过完全随机设计的因子试验，在不同水平的干旱胁迫下播种这些基因型。在幼苗期收集根长和茎长、相对叶片水分含量、离体叶片水分损失、过氧化物酶含量和叶片组织中过氧化氢浓度的数据。
生物计量分析表明，记录参数的种质存在显著差异，同样基因型和水分胁迫的相互作用也存在显著差异。根据对水分胁迫的反应，将棉花种质分为八个聚类。在干旱条件下，基因型 Cyto-124 的 HO 含量最低，在胁迫环境下，基因型 Ali Akber-802 和 CEMB-33 的离体叶片水分损失最小。总体而言，根据形态和生化特征，SL-516 和 Cyto-305 被认为是耐旱的。基因型 1852-511、Stoneville 15-17 和 Delta Pine-55 的根长、过氧化物酶活性值较低，HO 含量值较高。根据这些发现，这些基因型被宣布为耐旱。
根据对照和干旱胁迫条件下各种参数的不同反应对棉花种质进行分类。记录的参数，特别是相对叶片水分含量和生化分析，可以用于筛选大量棉花种质资源以适应水分亏缺条件。此外，本研究中鉴定的耐旱基因型可用于棉花育种计划，以开发改良品种。
