Production of haploid and doubled haploid plants of melon (Cucumis melo L.) for use in breeding for multiple virus resistance

Abstract

We have developed improved procedures for recovery of haploid and doubled haploid (DH) melon plants, using hybrids derived from crosses of lines with multiple virus resistance. Seeds formed after pollination with irradiated pollen were cultured in liquid medium for 10 days before excision of the embryos for further culture. This made it easier to identify the seeds containing parthenogenetic embryos, thereby reducing the effort required and increasing the percentage of plants recovered. The plants obtained (approximately 175) were transferred to a greenhouse for evaluation. Three fertile lines were identified, and selfed seeds were obtained for evaluating virus resistance. Flow cytometry of leaf tissues showed that two of these lines were spontaneous DH and the third was a mixoploid containing haploid and diploid cells. The other plants remained sterile through the flowering stage. Flow cytometry of 20 sterile plants showed that all were haploid. Attempts to induce chromosome doubling by applying colchicine to greenhouse-grown plants were unsuccessful. Shoot tips from the haploid plants were used to establish new in vitro cultures. In vitro treatment of 167 micropropagated haploid shoots with colchicine produced 10 diploid plants as well as 100 mixoploid plants. Pollen from male flowers that formed in vitro on the colchicine-treated plants was examined. High percentages of viable pollen that stained with acetocarmine were found not only in the diploids but also in >60% of the plants scored as mixoploid or haploid by flow cytometry. Efficient recovery of DH from hybrid melon lines carrying combinations of important horticultural traits will be a valuable tool for melon breeders.

Morphogenetic response of cotyledon and leaf explants of melon (Cucumis melo L.) cv. Amarillo Oro

“…Several protocols for melon have been described using different explants such as hypocotyls, cotyledons, leaves and roots (Moreno et al, 1985;Trulson and Shahin, 1986;Niedz et al, 1989;Bordas et al, 1991;Tabei et al, 1991;Souza, 1999;Souza, 2001;Lotfi et al, 2003). The results have shown that protocols using leaf explants were less efficient.…”

Evaluation of Factors Affecting Embryo-like Structure and Callus Formation in Unpollinated Ovary Culture of Cucumber (Cucumis sativus)

“…Both in vitro androgenesis and gynogenesis have been induced in cucurbit crops for doubled haploid production (Metwally et al, 1998;Lotfi et al, 2003;Song et al, 2007;Gałązka and Niemirowicz-Szczytt, 2013). However, many reports show low frequency of gynogenesis and/or regeneration rates that limit their success in breeding programs.…”

Screening for Cucumber Mosaic Resistant Lines From the Ovule Culture Derived Double Haploid Cucumbers

“…DHs can facilitate the selection of desired (e.g., disease-resistance) genotypes for breeding. Lotfi et al (2003) used a hybrid melon which showed resistance to various viruses as a donor for the production of DH melons. DH cucumber is produced by culturing the ovaries at one day before an thesis to induce new plants through cytogenesis.…”