Scion preconditioning and cytokinin treatment improved graft compatibility in Red Globe grape grafted on Dogridge rootstock

Abstract

Cultivation of 'Red Globe' grapes are gaining popularity in India's mild tropical climate owing to its bold berries, attractive red colour, and better shelf life, thus fetching a better price in the market. 'Dogridge' is the preferred rootstock in India because of its wide adaptability to different soils and climatic conditions, besides its tolerance to drought and salinity. Though most of the commercial grape varieties are grafted on 'Dogridge' rootstock, the success of grafting 'Red Globe' onto 'Dogridge' is little, or it needs repeated grafting for vineyard establishment. Hence, to improve the grafting success on 'Dogridge' rootstock, we tried different combinations of scion treatments. The scions were treated with cytokinin compounds like kinetin or benzyl amino purine (BAP) or a combination of hormones with scion preconditioning or etiolating and compared with the control. Among these treatments, scions preconditioned on mother vines for five days combined with treating them with BAP @ 100 ppm for 60 seconds before grafting, improved the grafting success to 68%. Biochemical and enzyme studies also indicated higher activity of antioxidant enzymes like peroxidase and polyphenol oxidase in the same treatment. Scion preconditioning and BAP treatment helped better callus production and vascular connectivity between stock and scion, contributing to better graft success. The role of biochemical parameters and antioxidant enzymes in improving graft success has been discussed.