The article presents the results of the research carried out to study the manifestation of performances of traits for cotton weight per boll, fiber yield and fiber length in the populations which were grown in 2020 in the conditions of Tashkent region and belonging to upland cotton varieties and lines created by breeders of a number of scientific research institutes operating in the Republic of Uzbekistan. At the end of the article, it was stated that forms such as Bukhara-102, T- 1391, T-1278, Mehnat, Yulduz, C-8290 showed higher results in terms of weight of cotton per boll, UzFA-710, Yulduz, T-19, T-1278, Kelajak varieties in terms of fiber yield, T- 1470, Bukhara-102, Kelajak, UzFA-707, C-6524, UzFA-710, T-1336, T-41 and T-1326 varieties and lines in terms of fiber length trait than other sources of research.