ROOTSTOCK STUDIES IN MANGIFERA INDICA L.

Rootstocks play an important role in the propagation of plants. It may modify form or stature, adapt a variety or species to a soil, fit in an incompatible climate, impart or resist disease to the scion, increase production, hasten maturity of crop, change the colour of the fruit, effect the flavour of the fruit, shorten life of the tree, increase the size of the fruit (3), develop vigour (Hatton, as quoted by Rogers and Beakbane, 5), effect salt tolerance (2) and influence storage capacity (7).

Very little work on this important aspect has yet been done in our country, particularly in mango. In the absence of any standard rootstock in mango, propagation is done on seedling stocks which are heterogenous in nature. Gunaratnam (1) recommended variety "Pullima" (Mangifera indica L.) which grows semi-wild in parts of Jaffna district, for use as stock on both budding cleft grafting. In a mango rootstock trial done at Sabour, no significant differences between the rootstocks could be found (6). However, in another mango rootstock trial, Oppenheimer (12) reported that the largest trees were produced on Sabre rootstocks, in spite of its dwarfing character and he made important recommendations for the mango growers. A perusal of the literature shows that no recommendations based on scientific findings are available in respect of suitable rootstock for important commercial mango variety, Dashehari as yet. Therefore, to study the effect of rootstocks on scion trial, a trial in 1959 was laid out at the Fruit Research Station, Basti.

The trial was laid out in a randomized block design having five different rootstocks as treatment, with four plants per treatment and replicated five times. Rootstocks used for Dashehari scion were four poly-embryonic varieties viz. Ambalavi, Mylepalium, Olour and Vellai Kolamban, and Seedling of Dashehari. The requisite number of seeds were sown in the nursery. One year old seedlings of healthy and uniform growth were selected and grafting was done with Dashehari scion. The plants thus prepared were planted in the field at a distance of 36' x 36' during 1959. Single external guard row was provided around the experimental area. Care was taken to provide uniform cultural treatments throughout the period of growth.