Improvement of two locally adapted cotton cultivars in earliness by induced mutations

Abstract

Seeds from two locally adapted cotton cultivars, Eva and Zeta-2, were irradiated by 300 Gy γ-irradiation in order to create useful variability for earliness within each cultivar, and then to select for desirable recombinations. Selection for earliness was applied in the M2 generation and the earliest 2% of the mutants were selfed for further evaluation. After eliminating the undesirable phenotypes, the remaining material was sown in progeny rows as the M3 generation. Selection for earliness based upon morphological and physiological characteristics resulted in 5 early mutants from cv. Eva and 3 early mutants from cv. Zeta-2. These lines were further evaluated the following year for earliness, yield, fibre, and seed quality in 3 locations across the Greek cotton belt, using a randomised complete block experimental design with 4 replications. Among the 5 early mutants of cv. Eva, only one was consistently early at all 3 locations, whereas the other 4 mutants showed significant differences in the first growth stages. From the 3 early mutants of cv. Zeta-2, one was consistently early at all 3 locations. Plant height, lint yield, length, micronaire, strength, etc., as well as oil %, protein %, and gossypol %, were not significantly different from the untreated checks.