SHARMA, K.R.MEENA, DHARM SINGH2017-02-072017-02-07200947113http://krishikosh.egranth.ac.in/handle/1/5810000385ABSTRACT The present investigation entitled, “Studies on relationship between resin duct characteristics and oleoresin yield in Chirpine (Pinus roxburghii Sargent)” was carried out in the laboratory of department of forest products and in the campus area of Dr Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan- 173230 (H. P.) with the objectives to study the relationship between morphological parameters and resin duct characteristics with oleoresin yield. The trees were classified into three oleoresin yield classes i.e., high resin yielders (HRY’s), medium resin yielders (MRY’s) and low resin yielders (LRY’s). The oleoresin yield showed increasing trend with increase in diameter at breast height and number of bore holes. The maximum oleoresin yield (853 g/hole/tree) was obtained from first bore hole (B1) with 40-45 cm diameter class (D3). Higher oleoresin yielders were recorded in trees having dark green (136 A) needle colour, followed by green (137 B) needle colour. Trees with yellowish- green (145 A) needles gave lowest oleoresin yield. The needle thickness, needle length and bark thickness showed association with oleoresin yield. The average value for resin ducts parameters was recorded maximum in HRY’s and minimum in LRY’s. The number of vertical resin ducts/mm2 was found to be maximum in a HRY (R-93) and maximum value for diameter of vertical resin ducts was noticed in R-11 and R- 74, and minimum value of diameter in LRY’s marked as R-20 and R-58. The number of horizontal resin ducts/mm2 was maximum in a HRY (R-93) and the minimum numbers were observed in LRY’s (0.50). The maximum value for diameter of a horizontal resin duct (108 μm) was recorded in two high resin yielding trees (R-11 and R-93) and minimum value of diameter (54 μm) was noticed in LRY’s. To predict the oleoresin yield multiple component analysis was conducted and a regression equation was formulated, which indicated that six characters, viz. needle length, bark thickness, number of vertical resin ducts, diameter of vertical resin ducts, number of horizontal resin ducts and diameter of horizontal resin ducts, contribute maximum to the resin yield.enirrigation, energy resources, biological phenomena, land resources, environment, wood, economics, seasons, manpower, plantingThesis