HETEROSIS BASED ON MALE STERILITY IN COTTON

Heterosis is a method of increasing productivity and is used in many crops. In cotton, heterosis is mainly related to yield and fiber length. Two male-sterile cotton lines ms 273 and ms 274 were included in crosses with five modern varieties: Chirpan-539, Natalia, Rumi, Helius and Nelina. Heterosis manifestations were found for productivity/plant (7.4-63.8%) and fiber length in the F1 hybrids. The cultivar Chirpan-539 and Rumi variety, with high GCA for fiber length and high variances of SCA, emerged as suitable for heterosis selection of this trait. The crosses 273 x Nelina and 274 x Nelina, with the highest productivity\plant (39.5-42.1 g) and the highest heterosis (61.9-63.8%), the second one with high SCA effects, are of interest for the heterosis selection of productivity. The crosses 274 x Chirpan-539 and 274 x Natalia, with the longest fibers (28.9-29.3 mm) and heterosis (2.1-3.5%), the first one manifested high SCA effects, are of interest for the heterosis selection of fiber length. The results obtained are encouraging for the development of heterotic selection and practical use of heterosis in cotton based on male sterility.