Development of a muskmelon cultivar with improved resistance to gummy stem blight and desired agronomic traits using gene pyramiding

Abstract

Gummy stem blight (GSB), caused by Didymella bryoniae (Auersw.) Rehm., is a severe disease affecting Cucurbitaceae crops including melons. The resistance of current melon varieties that carry a single Gsb resistance gene is insufficient to protect against the abundant variation of the D. bryoniae isolates. Pyramiding multiple Gsb resistance genes into melon cultivars is an effective way to develop a broad resistance spectrum and to increase the duration of GSB resistance. In this study, two resistance genes (Gsb-4 and Gsb-6) from two resistant accessions, PI482398 and PI420145, were pyramided into one variety using marker-assisted selection (MAS). The donor parent 4598 that contained Gsb-4 and Gsb-6 was hybridized with muskmelon Baipicui to produce BC<sub>1</sub>F<sub>1</sub> and BC<sub>2</sub>F<sub>1</sub>. Phenotyping and MAS enabled identification and pyramiding of two Gsb genes in individuals of F<sub>1,</sub> BC<sub>1</sub>F<sub>1</sub> and BC<sub>2</sub>F<sub>1</sub>. Field cultivation showed that individuals carrying both Gsb-4 and Gsb-6 had improved resistance to GSB and improved fruit quality. The results indicated that MAS-based pyramiding is an effective strategy for breeding melon cultivars with increased resistance to GSB.

Genome-Wide Characterization of NBS-Encoding Genes in Watermelon and Their Potential Association with Gummy Stem Blight Resistance

“…The ultimate target of both breeders and researchers is to develop GSB-resistant cultivars, since chemical treatment is not an environmentally suitable approach for controlling GSB [ 29 ]. Gene pyramiding is an effective way to increase the chances of conferring stable resistance to plant diseases, but disease resistance can break down due to increasing mutation rates in the pathogen population [ 9 , 30 ].…”

“…It is difficult to properly control GSB using chemical methods and the frequent use of fungicides is not desirable due to their negative impact on the environment [ 4 , 8 ]. Consequently, developing GSB-resistant watermelon cultivars containing major resistance genes through gene pyramiding represents the most environmentally sustainable and economically viable means of GSB management [ 4 , 9 ].…”

Gummy Stem Blight Resistance in Melon: Inheritance Pattern and Development of Molecular Markers

“…Gummy stem blight (GSB), which is caused by the fungal pathogen Didymella bryoniae (Auersw.) Rehm, is a devastating disease of cucurbitaceous crops, including melon, throughout the world [ 4 , 5 ]. Disease symptoms can appear on all parts of the plant (e.g., leaves, stems, and fruits), except the roots.…”

“…Limited success has been achieved in controlling GSB with chemical methods; therefore, the most effective means of GSB management is to use resistant cultivars [ 5 , 7 ]. The agricultural importance of this disease means that the search for genetic resistance has been ongoing for some time, yet, to date, most of the available GSB-resistant melon cultivars and breeding cultivars come from one line, plant introduction 140471 (‘PI140471’) [ 1 , 8 ].…”

Differentiation between Resistance and Susceptibility of Flax Cultivars to Powdery Mildew by Molecular Techniques

“…It allows rapid selection at all growing season, there by significantly shortening the breeding process (Poolsawat et al, 2017). Various molecular markers have been used in several crop breeding programs (Arunakumari et al, 2016, Kassa et al, 2017, Poolsawat et al, 2017, and Zhang et al, 2017.…”