Exploiting Rootstock Diversity: Enhancement of Growth, Stress Resilience, Physiology, and Molecular Regulation in Cucurbits

Cucurbitaceous vegetables hold a prominent position in horticultural production around the world. Cucurbits are cultivated intensively, covering 5% of total vegetable production in India. Prolonged and continuous cultivation of cucurbits led to outbreaks of diverse pests and diseases. Cucurbitaceous vegetables are also susceptible toward abiotic stress, which hinders their normal physiological functions. To overcome these barriers, the grafting technique was acknowledged as a promising solution. Watermelon, melon, and cucumber are the most grafted cucurbits. Bottle gourd ( Lagenaria siceraria ) is widely used as the rootstock; other than that, Cucurbita moschata , Cucurbita maxima , C. maxima × C. moschata , Cucurbita ficifolia , Cucumis metuliferus , Cucumis pustulatus , Luffa cylindrica , and many wild species of the cucurbitaceous family are also used for grafting. Each rootstock influences the scion differently depending on its genetic constitution. The effects of rootstock are reflected on the growth, physiology, and molecular aspects of the scion. The rootstock imparts tolerance to various biotic and abiotic stresses, especially most of the rootstocks used to confer tolerance for Fusarium wilt and drought due to their extensive and deep root system. The translocation of signaling molecules from rootstock to scion through graft union is accountable for the alteration in the expression of stress‐responsive genes, vigorous growth, and changes in hormonal balance in grafts. Multiple stress tolerance rootstocks like the interspecific hybrid squash rootstock ( C. maxima × C. moschata ) are emerging as a preferable choice for grafting. It is tolerant to Fusarium and Verticillium wilt, root and crown rot, drought, salinity and mineral toxicity. Through the evaluation of various wild species and interspecific hybrids, elite rootstocks can be identified, which can be used to alleviate stress and strengthen the cultivation of cucurbitaceous vegetables.