Effect of some growth regulators on haploid plant regeneration in eggplant (solanum melongena L.) anther culture

Eggplant (Solanum melongena L.) is an important species belonging to the Solanaceae family, rich in vitamins, minerals and carbohydrates, and is a vegetable with great economic value. The chromosome number of the plant is 2n = 2x = 24 and it ranks fifth among the most produced vegetables in the world. Eggplant is grown in both open fields and greenhouses in Türkiye, and there are many problems that limit its production and quality. Although it is an important agricultural product in Türkiye, eggplant breeding is mostly done with classical breeding methods. The main reason for this is that effective biotechnological techniques that can be integrated into classical breeding methods have not been developed sufficiently. Classical breeding methods, which normally require a long process of 10-15 years, can be shortened by 1/3 when supported by appropriate biotechnological methods. In this study, Aydın Siyahı variety was used to develop an efficient protocol for haploid embryo induction. For this purpose, BAP, IAA and GA3 plant growth regulators were added to MS FeNa-EDTA (PhtoTech Labs Catalog No: 5800) medium at different concentrations (1, 2, 3, 4, 5 mg/l) for anther culture study and the effects of these regulators on eggplant anther culture were investigated. Before the anthers were cultured, the most suitable microspore development stages were determined. Buds at the appropriate stage were collected daily and cold pretreatment was applied at +4°C for 24–36 h. The effectiveness of the various nutrient media prepared was evaluated on the parameters of direct regeneration (plant), anther that develops only root, callus formation, shoot formation from callus, callus that's develops only root, and rooted shoot formation from callus. The results obtained from this study revealed that there was callus induction at varying levels in hormone-applied media, with the highest rates observed in media containing 5 mg/l GA3 (15.2%) and 3 mg/l BAP (11.8%). While no shoot formation was observed in media containing IAA and GA3, shoot formation was observed in media containing 3 mg/l BAP (22.04%). Although shoot regeneration occurred in 3 mg/l BAP, these structures did not form roots. However, the anther callus and shoot results presented in this study are important in terms of revealing the effects of these growth regulators (BAP, IAA and GA3). These findings indicate that the applied hormones partially induced morphogenesis, but the Aydın Siyahı variety may have low androgenic potential or protocol optimization may be needed.