Effect of medium composition on in vitro ovary culture of cucumber

Ovary culture is among the most effective techniques for haploid induction in horticultural crops, including cucumber. The application of doubled haploid technology can significantly accelerate cultivar development by enabling the rapid production of homozygous inbred lines. This study evaluated the effects of culture medium combinations of plant growth hormones (2,4-D, NAA, IAA, IBA, PUT, BAP, KIN, TDZ) on haploid induction in cucumber via ovary culture. Four induction and five regeneration media were tested across four cucumber varieties: Beith Alpha, PTK40, Botanik, and Sardes. The highest embryo formation rate (88%) was observed in the Botanik variety, followed by Sardes, PTK40, and Beith Alpha, particularly on induction medium supplemented with 2,4-D and PUT. Plant regeneration was achieved on a medium containing IAA and BAP. Flow cytometric analysis of twenty randomly selected plants confirmed that all were diploid, with no haploids detected. This outcome indicates that the primary objective of inducing haploid plants was not successfully accomplished. These findings highlight substantial limitations in the current induction protocol and underscore the need for further optimization to improve haploid recovery efficiency. The authors recommend more research to develop and improve ploidy level stability for cucumber ovary culture.