The effects of different colchicine applications on spontaneus chromosome doubling of embryos in pepper (Capsicum annuum L.) anther culture

Anther culture is the most preferred method for obtaining pure lines that play an important role in the development of hybrid varieties. Spontaneous chromosome doubling can be observed in the plants obtained at the end of culture, due to the practices and media contents during culture. Different antimitotic substances are used for haploid plants that do not exhibit spontaneous chromosome doubling to transition to diploid structure. Among these antimitotic substances, colchicine is the most used. Colchicine is a costly compound and needs to be used in high doses in in vivo applications. In this study, the effects of colchicine on the promotion of haploid embryo formation and spontaneous chromosome doubling in Capsicum annuum anther culture were investigated. Colchicine 0.0%, 0.3%, 0.4% and 0.6% was applied to anthers for 14 and 21 days in semi-solid and bi-layer media.. Embryos developing from colchicine-free medium were immersed in 0.5% colchicine solution for 2 hours for chromosome doubling. The embryo, developing plant and SDH plant rates obtained from the applications were calculated. In order to determine the ploidy level in plants, pollen in flowers, seeds in fruits, number of stomata in leaves, stomata width and length were examined. The highest embryo formation rate, 21.03%, was obtained from a dose of 0.6% colchicine in semi-solid medium for 14 days. The development rates of embryos into plants obtained from 0.3%, 0.4% and 0.6% colchicine doses added to the nutrient medium; It was determined as 52.75%, 50.33% and 47.56%, respectively, in the semi-solid medium and 27.21%, 47.32% and 36.11%, respectively, in the bi-layer medium. The number of stomata in plants obtained from the control group was evaluated as 12-15, in the donor plant as 10-12, in SDHs developed from colchicine-containing media as 10-15, and in haploids as 17-26. It has been observed that the addition of colchicine to the nutrient medium has a significant effect on the embryo rate, plant regeneration and the number of spontaneous double haploid (SDH) plants. Semi-solid medium was found to be more successful than bi-layer medium.