Rooting behavior and biochemical changes in relation to IBA concentrations in different grape rootstocks

Indole-3-butyric acid (IBA) treatments at different concentrations (750, 1000, 1500 and 2000 ppm) were given to the hardwood stem cuttings of six grape rootstocks before planting in rooting medium. The bud sprouting success of cuttings was not significantly influenced by the IBA treatments. However, the days taken for bud sprout were significantly reduced with 750 ppm concentration. Shoot length, root length, leaf area and number of root primordia exhibited varied response among rootstocks. Biochemical analysis showed significant changes in sugar and protein content of leaves. Higher protein content was recorded at 750 ppm IBA in 1613C, St. George and 140-Ru rootstocks and was superior over other concentrations. Total phenolics content increased significantly with increase in IBA concentration in St. George. Considering the days taken for bud sprout, sprouting success and root primordia, 2000 ppm IBA was better for Dog Ridge. It can be concluded that 1000 ppm IBA concentration was for rooting success and growth in 1613C and 140-Ru. In 41-B and Freedom, the sprouting success was higher at 1500 & 2000 ppm. The numbers of root primordia also varied significantly among the rootstocks. Maximum numbers of root primordia were recorded in 1613C and St. George rootstocks as compared to all other rootstocks indicating their distinct genotypic behavior.