Agronomy Department, Faculty of Agriculture, Kafr El-Sheikh University, P.O. 33516, Kafr El-Shiekh, Egypt.
Cotton Breeding Department, Cotton Research Institute, Agriculture Research Center, Giza, Egypt.
Sci Rep. 2022 Sep 8;12(1):15227. doi: 10.1038/s41598-022-18966-3.
This work was carried out to select cotton genotypes adapted to semi-arid climate conditions cultivated under irrigation for high yields and the standards of the fiber quality properties required by the textile industry. Also to determine the predicted and realized gains from different selection indices to improve some economic characters under water stress conditions. Except for lint percentage and Pressley index, F4 generation reduced PCV and GCV values for all studied characters due to reduction in genetic variability and heterozygosity due to different selection procedures that exhausted a significant part of variability. Except for fiber length and micronaire reading, mean performance in the F4 generation was revealed to be higher than those in the F3 generation for all studied characters. However, micronaire reading was lower (desirable) in F4 than F3 generation. Generally, genotypic correlations were higher than phenotypic correlations. Direct selection for lint index (Ped.3) was the most efficient in improving lint cotton yield/plant and bolls/plant. However, the multiplicative index involving all studied characters (I.5) exhibited the highest values for boll weight. Also, the Ped.2 index (direct selection for lint percentage) proved to be the most efficient in improving seed and lint indexes. Direct selection for lint cotton yield/plant (Ped.1) could produce the highest desirable values for lint percentage and seed per boll with a relatively reasonable yield. A selection index involving yield and its components (I.3) is recommended in improving uniformity index, fiber strength, and micronaire reading. The superior five families released from these indices in F4 generation exceeded the better parent for lint cotton yield/plant, bolls/plant, boll weight, seeds/boll, lint index, and reasonable fiber traits. These families could be continued to further generations as breeding material for developing water deficit tolerant genotypes.
这项工作旨在选择适应半干旱气候条件下灌溉种植的棉花基因型，以实现高产和满足纺织工业所需的纤维质量标准。同时，确定不同选择指数在水分胁迫条件下提高一些经济性状的预期和实际增益。除了纤维百分率和普雷斯利指数外，由于遗传变异和杂合性的减少，F4 代降低了所有研究性状的 PCV 和 GCV 值，因为不同的选择程序耗尽了大部分变异。除了纤维长度和马克隆值读数外，F4 代的平均表现显示出所有研究性状的表现均高于 F3 代。然而，F4 代的马克隆值读数（理想值）低于 F3 代。一般来说，基因型相关系数高于表型相关系数。直接选择 lint 指数（Ped.3）是提高 lint 棉花产量/株和铃/株的最有效方法。然而，包含所有研究性状的乘法指数（I.5）在铃重方面表现出最高的值。此外，直接选择 lint 百分率的 Ped.2 指数（直接选择 lint 百分率）被证明是提高种子和 lint 指数的最有效方法。直接选择 lint 棉花产量/株（Ped.1）可以在相对合理的产量下产生最高的理想 lint 百分率和每铃种子数。一个涉及产量及其组成部分的选择指数（I.3）建议用于提高均匀度指数、纤维强度和马克隆值读数。在 F4 代中，从这些指数中释放的前 5 个家族在 lint 棉花产量/株、铃/株、铃重、种子/铃、lint 指数和合理纤维性状方面均超过了更好的亲本。这些家族可以继续进一步的世代，作为培育耐旱基因型的育种材料。
