Seasonal influences on the rooting response of Chir pine (Pinus roxburghii Sarg.)

Rooting ability of the vegetative cutting depends upon the various factors: age, size, and diameter of cutting, season, rooting substrate and con- centration of the applied growth hormone. For assessing the seasonal varia- tion in rooting ability of shoot, cuttings were taken from 4 year old hedges. Shoot cuttings were collected after every two months of hedging spring (March), summer (June), autumn (September) and winter (December) and treated with 4000 ppm Indole Butyric Acid (IBA), mixed with talc powder and planted in vermiculite filled beds. Suitable control was also maintained, wherein only talc powder was applied to the basal portion of cuttings. Pe- riodical observations were taken on cuttings, with regard to root initiation. The cuttings were uprooted after 12 weeks of planting and observations were recorded. Highly significant differences were observed between root length, shoot length, number of roots per cutting and rooting percentage. This has led to the evaluation of a standard technique for application of mass clonal propagation of Chir pine during summer season (June), which would result into a good success in rooting percentage. This technique could also be helpful in the establishment of germplasm banks of desired geno- types and Clonal Seed Orchards (CSOs). Further, this will also help in over- coming the problem of stock and scion incompatibility, which is commonly faced, when Clonal Seed Orchards are established through grafted material. Keywords seasonal variation, rooting ability, Chir pine, vegetative multipli- cation Garden (VMG), Clonal Seed Orchard (CSO).