Greenhouse Evaluation of Melon Rootstock Resistance to Monosporascus Root Rot and Vine Decline as Well as of Yield and Fruit Quality in Grafted ‘Inodorus’ Melons

Abstract

Melons (Cucumis melo L.) are generally grafted onto Cucurbita rootstocks to manage soilborne pathogens such as Monosporascus root rot and vine decline (MRR/VD) and Fusarium wilt. However, grafting onto Cucurbita rootstocks reportedly results in the reduction of fruit quality. In this study, the resistance to MRR/VD, yield, and fruit quality of melons grafted onto melon rootstocks were evaluated under greenhouse conditions. Eight melon rootstocks (R1 to R8) were used and the inodorus melon 'Homerunstar' was used as scion. Melon rootstocks R1 to R6 were selected based on resistance to MRR/VD under greenhouse conditions. Non-grafted 'Homerunstar' and plants grafted onto squash interspecific hybrid 'Shintozwa' rootstock (Cucurbita maxima D. × C. moschata D.) served as controls. Grafted melons were cultivated in the greenhouse infested with Monosporascus cannonballus during two growing seasons (summer and autumn). The responses to MRR/VD, yield, and fruit quality differed depending on the rootstocks and growing season. The melons grafted onto 'Shintozwa' exhibited less severe disease symptoms and higher survival rates than non-grafted melons in both seasons. While the melon rootstocks in the summer cultivation did not increase the survival rate compared to non-grafted melons, the melon rootstocks R1 and R2 in the autumn cultivation led to higher survival rates. The melon rootstocks resistant to MRR/VD increased the percentage of marketable fruits and marketable yields. Grafting onto the melon rootstocks caused little or no reduction of fruit quality such as low calcium content, fruit softening, and vitrescence, especially in lower-temperature autumn season. Accordingly, these results suggest that grafting onto the melon rootstocks may increase the tolerance to MRR/VD and the marketable yield without a reduction of fruit quality.

Interspecific hybrids of wild Cucumis species (‘Fian’ and ‘Fimy’): new rootstocks for melon highly resistant to biotic soil stress

“…In melon (Cucumis melo L.), an increase of fruit size and seed cavity (Verzera et al, 2014) or modifications of flesh firmness (Colla et al, 2006;Zhao et al, 2011) as a result of grafting have been described. Vitrescence (Jang et al, 2014), flesh colour variations, and changes in pH and soluble solids content have also been reported (Colla et al, 2006;Verzera et al, 2014).…”

Effect of Low-Temperature Tolerant Rootstocks on the Growth and Fruit Quality of Watermelon in Semi-Forcing and Retarding Culture

“…The vigorous root growth of rootstock has been reported to promote the growth of grafted seedlings [16,[36][37][38]. 'Shintozwa' rootstock has a vigorous root system [39].…”

Food quality attributes of melon (Cucumis melo L.) influenced by grafting

“…The development of vitrescence in melons is often used to refer to the effect of grafting (Jang et al, 2014;Rouphael et al, 2010;Colla et al, 2017). Softening and vitrescence can usually be observed due to forcing in autumn and in cultivation in summer when a variety with traits of lower flesh firmness is grafted to "Shintosa" rootstock.…”

“…Softening and vitrescence can usually be observed due to forcing in autumn and in cultivation in summer when a variety with traits of lower flesh firmness is grafted to "Shintosa" rootstock. Jang et al (2014), revealed that plants grafted to "Shintosa" rootstock developed vitrescence in 89% of the plansts, in contrast only 50% of plants grown on their own roots showed this problem. Plants grafted on melon rootstock showed an even lower vitrescence development rate.…”