A. STOILOVA and D. DECHEV
Cotton and Durum Wheat Research Institute, BG-6200 Chirpan, Bulgaria
STOILOVA, A. and D. DECHEV, 2002. Genotype environment interaction and phenotypic stability of economic traits in cotton lines. Bulg. J. Agric. Sci., 8: 485–491
The genotype x environment interaction and stability of 14 breeding lines and 3 cultivars of G. hirsutum L. cotton were investigated during 1996–1998. Twelve lines and one cultivar contained in their genotypes germplasm of G. barbadense L. species. The years of the investigation appeared to be as different ecological environments. The folowing stability parameters were calculated: coefficient and variance of the linear regression (bi and S2di) (Eberhart and Russele, 1966); stability variances (σ2i and S2i) of Shukla (1972) and YSi index of Kang (1993).
It was found that the cotton lines and cultivars tested interacted significantly with environmental conditions (years) in terms of total and September yields, and of fibre output. For efficient breeding of these traits, the genotypes have to test in different years. There were no significant genotype x environment interaction for the fibre length, the boll weght and for the index of earliness. Efficient selection for these three traits should be conducted independent on the environmental conditions. A breeding usefull stability was observed in all three traits, with a significant genotype – by-environment interaction. The lines Nos. 400 and 412 had a superior combination of yield and stability simultaneously; the standard cultivars Chirpan-603 and Beli Izvor – of fibre output and stability. The lines Nos. 364, 431, 412 and cv. Avangard-264, containing G. barbadense L. germplasm responsible for the longer fibre, showed high stability for the traits with significant genotype x environment interaction, are recommended as very valuable in cotton breeding programs.