Rootstocks influence granulation in Kinnow mandarin (Citrus nobilis x C. deliciosa)

A study was conducted on Kinnow mandarin to determine the incidence and degree of granulation, and whether the recommended rootstocks, viz. Troyer citrange (dwarfing), Karna Khatta (semi-vigorous) and Sohsarkar (vigorous) influence granulation. Standard procedures were followed to observe the incidence and degree of granulation, diastase and pectinesterase enzyme activities and pheno-physiological fruit characteristics. The incidence of granulation in Kinnow was observed to be as high as 25.6%, which was influenced by different rootstocks, being very high for fruit from trees on Sohsarkar (38.3%) and very low for fruit from trees on Troyer citrange (5.9%). Pectinesterase and diastase enzyme activities, which have a close relationship with granulation, were lower in granulated fruit than in normal (healthy) fruit, and were significantly influenced by different rootstocks. The highest activities of these enzymes were exhibited by Sohsarkar and lowest by Troyer citrange. Granulated fruit were larger than normal fruit, but were inferior in quality characteristics. In general, all quality characteristics were significantly influenced by rootstock. Kinnow fruits from trees on Troyer citrange were smaller, but were superior in quality characteristics compared with fruit from trees on Karna Khatta and Sohsarkar rootstocks.