ISHS Acta Horticulturae 1404: IV Asian Horticultural Congress - AHC2023
Evaluation of Cucumis zambianus as a genetic resource for Fusarium wilt resistance in melon |
| Authors: | M. Yamaga, Y. Matsumoto |
| Keywords: | Cucumis melo, embryo, interspecific cross, ovule, pollen tube |
| DOI: | 10.17660/ActaHortic.2024.1404.130 |
| Abstract:
Fusarium wilt of melon, caused by Fusarium oxysporum f. sp. melonis, is one of the most destructive melon diseases, causing considerable damage to melon production worldwide. In particular, as no melon lines are resistant to race 1.2y Fusarium oxysporum f. sp. melonis, genetic resources are required for breeding. Although some wild Cucumis species are resistant to Fusarium wilt of melon, these cannot be used for melon breeding because of strong reproductive barriers. However, among these species, C. zambianus showed slight inhibition of pollen tube elongation and high fruiting rate when crossed with melon. Therefore, it was considered a promising genetic resource for melon interspecific hybridization. In this study, we investigated the cross compatibility of C. zambianus with melon and embryo rescue methods. Furthermore, resistance of C. zambianus to Fusarium wilt of melon was evaluated. We examined the pistil of C. zambianus × melon, which showed an elongated pollen tube in the melon stigma compared to that of C. zambianus. Although many viable ovules were observed at 14- and 21-days after pollination (DAP), the number of viable ovules decreased at 28-DAP. In the ovule cultures, the ovules from self-pollinated C. zambianus mature fruits showed a higher percentage of germination. The percentage of callus formation increased as the fruits developed. Although the ovules from C. zambianus × melon did not germinate, some green ovules were observed. In previous studies, greening of the embryo was rarely observed in melon interspecific crosses. Therefore, embryo rescue would be feasible using the 21- or 28-DAP embryos. Furthermore, two accessions showed high resistance to race 1.2y. Therefore, C. zambianus may represent a promising genetic resource for introducing resistance to wilt of melon. | |
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