Phenotypic stability for economic traits of Bulgarian and foreign cotton varieties | Phenotypic stability for economic traits of Bulgarian and foreign cotton varieties

إنجليزي. The interaction genotype × environment and stability for most important economic traits of 31 Bulgarian and foreign cotton varieties were studied in 2016 – 2019. The years of research were used as different ecological environments. To evaluate the stability, different stability methods were used: the stability variances (σ2i, S2i) of Shukla (1972), the ecovalence (W2 i) of Wricke (1962), the parameter YSi of Kang (1993) and the regression parameters (bi, S2di) of Eberhart & Russel (1966) (for the seed cotton yield only). There was significant genotype × year interaction for all traits under study. Stability was found for all traits, some genotypes showed stability for two traits. According to the regression parameters (bi and S2 di), regarding seed cotton yield, the varieties Helius, Trakia, possessing high productivity, Dorina and Chirpan-539 (standard variety) showed a relatively stable performance in different year conditions. The Helius variety, combining high yield and stability according to the regression and variance parameters, outlined as the most valuable for the cotton production. Viki and Denitsa varieties, high yielding, showed specific adaptation to favorable environments and they also were very valuable for implementation in the production. The Greek variety 791-169 combined high average level for the boll weight (5.5 g) and high stability. The Viki, Avangard-264, Eva and Vega varieties (boll weight 5.4-5.5 g) also showed stable performance on all stability parameters. The Viki variety emerged as the most valuable in terms of ginning out turn, combining high mean value (36.1%) and stability. The Boyana and Nelina varieties showed also stable performance (ginning out turn 35.3-35.7%). The varieties Natalia, Dorina, Perla-267 and Colorit in fiber length were compared with the foreign ones and had stable performance by all stability methods. Given the estimates of the parameter YSi and the overall performance according to the variances σ2i, S2i and ecovalence Wi 2, the varieties Eva, Natalia, Millennium, Perla-267 and Colorit combined best 1st fruiting branch height and stability, which makes them very valuable for the cotton breeding programs.

البلغارية. The interaction genotype × environment and stability for most important economic traits of 31 Bulgarian and foreign cotton varieties were studied in 2016 – 2019. The years of research were used as different ecological environments. To evaluate the stability, different stability methods were used: the stability variances (σ2i, S2i) of Shukla (1972), the ecovalence (W2 i) of Wricke (1962), the parameter YSi of Kang (1993) and the regression parameters (bi, S2di) of Eberhart & Russel (1966) (for the seed cotton yield only). There was significant genotype × year interaction for all traits under study. Stability was found for all traits, some genotypes showed stability for two traits. According to the regression parameters (bi and S2 di), regarding seed cotton yield, the varieties Helius, Trakia, possessing high productivity, Dorina and Chirpan-539 (standard variety) showed a relatively stable performance in different year conditions. The Helius variety, combining high yield and stability according to the regression and variance parameters, outlined as the most valuable for the cotton production. Viki and Denitsa varieties, high yielding, showed specific adaptation to favorable environments and they also were very valuable for implementation in the production. The Greek variety 791-169 combined high average level for the boll weight (5.5 g) and high stability. The Viki, Avangard-264, Eva and Vega varieties (boll weight 5.4-5.5 g) also showed stable performance on all stability parameters. The Viki variety emerged as the most valuable in terms of ginning out turn, combining high mean value (36.1%) and stability. The Boyana and Nelina varieties showed also stable performance (ginning out turn 35.3-35.7%). The varieties Natalia, Dorina, Perla-267 and Colorit in fiber length were compared with the foreign ones and had stable performance by all stability methods. Given the estimates of the parameter YSi and the overall performance according to the variances σ2i, S2i and ecovalence Wi 2, the varieties Eva, Natalia, Millennium, Perla-267 and Colorit combined best 1st fruiting branch height and stability, which makes them very valuable for the cotton breeding programs.