Direct regeneration of haploid or doubled haploid plantlets in cucumber (Cucumis sativus L.) through ovary culture

Abstract

This paper reports a simple and effective method of directly producing cucumber plants through unfertilized ovary culture. The paper involves an experiment investigating factorial interactions between TDZ treatment, cold pretreatment, genotypes of cucumber, to improve plant induction. Cold pretreatment was effective in stimulating the ovary. The results showed that cold pretreatment for 4 days, TDZ for 0.06 mg·L−1, the interaction with genotype can be used as an effective strategy to improve the efficiency of gynogenesis. The plant regeneration induction rate was highest (79.3%). In addition, we observed the process of cucumber megasporogenesis and plant regeneration. The plants obtained from ovary culture of cucumber were identified as diploid or haploid by flow cytometry, consistent with the results of chromosome counting. The diploid plants were further identified as pure doubled haploid using simple sequence repeats (SSR). The doubling treatment we used was one of the simplest and most effective methods, completed in a short time (1 h) with a doubling rate of 75%. The acclimation rate for the surviving was 70%. This work provides a basis for promoting haploid breeding in cucumber.