The conducted study, with focus on the earliness and opening rate of bolls, and other economic traits of introgressive cotton lines, was carried out from 2017 to 2019 at the Institute of Genetics and Plant Experimental Biology, and Genetics and Evolution Biology Department, in Chirchik State Pedagogical Institute, Tashkent, Uzbekistan. Overall, the introgressive cotton lines were found to ripen two to 13 days earlier than a standard cotton cultivar C-6524. Particularly, in line L-РСМ, the vegetation period took 109 days and matured 12.3 days earlier than a standard cultivar check. According to the boll weight, the selected cotton lines were identified to have the best performance, as well as, good germination ability of seeds. The cotton line, Т-138, was found highly resistant to strains of Fusarium oxysporum f. sp. vasinfectum pathogenic fungi, while the lines, L-РСМ and L-138, had 80% to 100% resistance to Verticillium dahliaе fungi. The cotton lines, L-РСМ and L-141, were not infected with Fusarium solani fungi. The cluster analysis revealed that according to the economic traits, the first cluster included lines L-24 and L-138 and were found to be closely related to each other. The line, L-РСМ, was included in the third cluster, and it was found that this cotton line was among the cultivars with the best performance for all the valuable economic traits. The comparative analysis of cotton lines resulted in a creation of a new medium-fiber cotton cultivar “Niso,” with the productivity of 3,830 to 5,650 kg ha-1, boll weight of 6.0 to 6.7 g, boll opening at 109.0 to 112.0 days, type IV fiber, 1000-seed weight of 118.0 to 120.0 g, fiber percentage ranging from 36.9% to 41.4%, fiber length at 34.0 to 35.9 mm, and relative tensile strength (34.6 cN/tex). Cotton lines obtained on the basis of intergenomic introgression methods were included in the leading “Cotton gene pool” (Reference of the Academy of Sciences of the Republic of Uzbekistan №4/1255-2473 dated November 12, 2020). These introgressive cotton lines made it possible to enrich the collection of cotton, to evaluate wild cotton species, and to form a system of information and analysis of the electronic database of adaptable stress factors and genetically enriched samples.
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