Grafting in cotton: A mechanistic approach for stress tolerance and sustainable development

Abstract Grafting is a classical technique to increase plant stress resistance and yield in horticultural crops. This review takes cotton (Gossypium spp.) as an example to summarize the application of grafting in sustainable development for the following subjects: (1) cotton production, such as improving stress tolerance, increasing nutrient and water use efficiency, and cultivating cotton perennially for high yield; (2) cotton breeding, such as conserving and propagating special germplasms, utilizing heterosis, breeding new varieties, improving the survival rate of transplanted plantlets, and accelerating virus-induced gene silencing (VIGS); and (3) cotton physiology and molecular biology research, such as the mechanism underlying root-shoot communication. In particular, cotton is a unique non-horticultural field crop, which can grow annually or perennially, depending on winter temperature. Therefore, cotton grafting has some unique aspects, e.g., annual cotton cultivars can be used in perennial cultivation when grafted on cold-resistant rootstocks to improve the over-winter survival abilities, and graft-propagated male sterile plants can be used for multi-year heterosis utilization in near tropics, which could be used to build a sustainable agricultural system. Moreover, future promises associated with grafting have been presented and discussed, such as whether cotton grafting could promote the exchange of genetic material (especially DNA) between rootstock and scion, resulting in stable inheritable variations that remains to be verified by molecular genetics.