Budburst in Sultana grapevine as influenced by salinity and rootstock

Abstract

The time to budburst in Sultana grapevine growing on its own root system, or else grafted to Dogridge, 161 3, Harmony, Ramsey (often incorrectly referred to as Salt Creek) rootstocks, was studied in plants that had been irrigated with 0, 12.5, 25, 50 or 75 mM solutions of chloride salts under glasshouse conditions during the previous growing season. Budburst was delayed on scions grafted to Ramsey and Dogridge rootstocks. Increased chloride concentration within canes was negatively correlated with time to budburst for all of the rootstock combinations. Accounting for temperature variation during the period of budburst did not affect the relation between time to budburst and chloride concentration within canes. Correlation of mean time to budburst (both on a day basis and a temperature summation basis) with mean chloride content for each rootstock at each level of salt treatment yielded a linear relation (P < 0.001), in which 64-68% of the variability in time to budburst was accounted for by chloride concentration in canes. An increase of 0.1% in cane chloride advanced budburst by 4.2 days and reduced temperature summation to budburst by 327 degree-hours.