Archives of Current Research International

Ethylene-releasing compounds such as ethephon (commonly known as ethrel) are also used in commercial cultivation to shift the floral balance toward femaleness and enhance yield potential.  Most of the available research on PGR-induced changes in cucumber sex expression has been conducted under controlled or semi-controlled conditions, with limited studies addressing their comparative effects under open-field environments. This gap in research is particularly significant, considering the fluctuating environmental variables in field settings that may influence hormonal responses. The study was conducted from February to May 2021 at the Vegetable Research Farm, Department of Horticulture, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi (U.P.), India. Cucumber (Cucumis sativus L.), a monoecious species, was recognized as the second most widely cultivated cucurbit after watermelon. As sex expression played a critical role in influencing yield, the experiment aimed to evaluate the effects of various plant growth regulators (PGRs) gibberellic acid (GA₃), naphthalene acetic acid (NAA), silver nitrate (AgNO₃), and ethrel applied at three concentrations alongside a control. The experiment followed a randomized block design (RBD) with thirteen treatments and three replications under open-field conditions. Significant variation (p < 0.05) was observed among treatments for all phenotypic traits. Ethrel at 300 ppm exerted the strongest feminizing effect, resulting in the highest number of female flowers per vine (23.00), the earliest female flower initiation (38.00 days), and the lowest sex ratio (0.48). In contrast, AgNO₃ at 375 ppm induced the highest number of male flowers (24.33) and the highest sex ratio (1.66). GA₃ promoted early flowering while maintaining a balanced sex ratio, whereas NAA increased both male and female flower production without significantly altering sex expression. Control plants exhibited delayed flowering (45.33 days) and a higher nodal position for the first female flower (12.22). Overall, Ethrel proved to be the most effective PGR in enhancing femaleness, highlighting the potential for hormonal manipulation to regulate sex expression and improve cucumber yield. The findings highlighted how targeted hormonal interventions shaped floral dynamics effectively. Utilizing such plant growth regulators has proven valuable for strategic crop planning, hybrid seed production, enhanced yield outcomes and optimizing cucumber cultivation practices.