Significance of sources of valuable traits for cotton breeding

Purpose. Select valuable samples from the collection of cotton on the basis of “number of open bolls per plant” and “weight of raw cotton from one boll” for further use in the breeding process when creating new varieties and their impact on productivity. Methods. During 2002–2019 on the fields of selection crop rotation of the selection department of the Institute of Irrigated Agriculture of the National Academy of Sciences, 282 samples of cotton of different ripeness groups were studied. Results. Among the stu­died cotton gene pool, in 20.4% of samples, the number of bolls per plant was very small – < 65–75%, in 26.8% – small, in the remaining (52.8%) samples, an average number of open bolls was formed. The analysis of the boll mass indicators showed that 16.0% of the samples had a very small boll (less than 3.0 g), most of the collection – 66.0% had a small boll (3–4 g); average (5.0–6.0 g) – 18.0%. It was revealed that there is the most significant direct relationship between the productivity of samples and the number of open bolls per plant. The equation for the correlation-regression dependence of the productivity of one plant on the number of open bolls per plant is: y = 0.1807x – 0.5292; Coefficients: R2 = 0.852; r = 0.923. A direct positive dependence was observed in the samples of UF080000 ‘Pidozers­kyi 4’, UF0800027 ‘Populiatsiia 3’, UF0800241 ‘Populiatsiia 9’, UF0800029 ‘417 U’, UF0800228 ‘3737 U’, UF08000 ‘K 71’, UF0800056 ‘Mariia’, UF0800206 ‘1086/94’. The maximum productivity, from 45.0–49.2 g, was noted in the early matu­ring samples of the collection, compared with varieties that had a long vegetation period and productivity from 33.0 to 43.0 g. The excess over the standard is from 2.5 up to 6.7 g and from 9.5 to 0.5 g/plant, respectively. Conclusions. For the first time in the conditions of the Southern Steppe, the most significant direct relationship between the producti­vity of genotypes and the number of open bolls per plant was revealed – r = 0.923. The maximum productivity – from 45.0 to 49.2 g – was observed in early maturing samples of the collection. In the course of many years of cotton gene pool research, sources of valuable traits were identified.