Response of Two Local Varieties of Onion to Chemically Induced Male Sterility

The research was carried out during two agricultural seasons 2020 and 2021 at the General Commission for Scientific Agricultural Research in Damascus. The objective was to study the response of two local varieties of onion plants to three chemical treatments, GA 3 (250, 500, and 1000 mg/l), clothes washing powder (5, 10, and 15 g/l), 2,4-D (0.1, 0.5, and 1 ml/l) to induce artificial male infertility. The experiment was designed as a randomized complete block design with four replicates . The results showed the efficiency of used chemicals in inducing male sterility in both varieties . The 1000 mg/L treatment of GA 3 was superior and significantly affected flowering parameters (inflorescence diameter, number of flowers per inflorescence, number of set flowers, percentage of flower setting) of both varieties Baladi red (10.03 cm, 1077.9 flower/inflorescence, 5 set flowers/inflorescence, and a percentage of 0.44%) and Salmon white (9.33 cm, 1084.2 flower/inflorescence, 5.1 set flowers/inflorescence, and a percentage of 0.47%), compared to the controls (7.67 cm, 695.1 flower/inflorescence, 495.78 set flower/inflorescence, 71.43%; 8.02 cm, 652.9 flower/ inflorescence, 545 set flower/inflorescence, and 82.76%, respectively). This was reflected positively in decreasing seed productivity per inflorescence to 0.009 g in Baladi red, 0.003 g in Salmoni white compared to the controls (8.86 g, 10.89 g). GA 3 can then be considered to have a selective effect on reducing or de-masculinize flowers, thus inducing male sterility and facilitating the production of F1 hybrid seeds without the need for back crossing within future breeding programs.