Effect of indole-butyric acid (IBA) and wounding on rooting ability and vegetative characteristics of apple rootstock cuttings under Nepal conditions

Abstract

Use of seedling rootstocks is widespread in Jumla and research on the evaluation of clonal rootstocks for propagation has still not started. Study on the concentration of IBA and wounding effect in cuttings is also deficit. Therefore, this investigation was carried out in the Hi-tech Greenhouse of Kalika nursery in Jumla, Nepal from February to July, 2018 to investigate the rooting response of MM111 apple rootstock to wounding (with or without) and various Indole-Butyric Acid (IBA) concentrations (0, 2000, 2500 and 3000 ppm). The experiment was laid out in a factorial Complete Randomized Design by preparing cuttings of 20 cm length and 5 to 10 mm diameter and planting them in rooting media made by mixing perlite, cocopeat, forest soil and vermicompost in 1:1:1:1 ratio after 15 second of quick dip in IBA solution. All the rooting and vegetative parameters were significantly affected by different concentration of IBA solution and wounding. The results revealed minimum number of days to first sprouting (15.50), highest rooting percentage (68.52%), highest number of roots per cutting (23.11), highest length of the longest root (22.83 cm), maximum diameter of main sprout (2.92 mm), maximum number of leaves at 86 DAT(20.06), 93 DAT(22.50) and 100 DAT(30.17) in the cuttings treated with IBA 2000 ppm. Increasing the IBA concentration beyond 2000 ppm produced negative effects. Similarly, wounding resulted in better root and shoot parameters of cuttings than with no wounding. The rooting percentage (57.4%), number of roots per cutting (21.83), length of the longest root (20.96 cm), diameter of the main sprout (2.66 mm) were significantly higher in wounded cuttings which also recorded the lower days for first sprouting. The interaction effect was significant (p<0.01) only on the rooting percentage while all other parameters were non-significant. The results indicated that 2000 ppm IBA with basal wounding perform better than other treatments.