160 JAVAID AHSAN AND M.I.R. KHAN 



GENETIC VARIATION 



Because of the extensive and discontinuous range of blue pine over 

 a variety of habitats, discontinuous genetic variation may exist. 



A project to investigate genetic variation in blue pine was started 

 in 1967 at the Pakistan Forest Institute, Peshawar. Material consisting 

 of twigs, cones, and seed is being collected from localities throughout 

 the range of blue pine in West Pakistan (Fig. 1) . The material is 

 collected from 10 trees representative of the stand in each locality. 

 Morphological and anatomical studies on the cones and needles are under- 

 way. Differences among characters of blue pines of the various habitats 

 only can be surmised at present. Definite results will be available only 

 after the study is completed. The interim results indicate that the blue 

 pine seed from the highly xeric habitat is small and reddish brown in 

 color, whereas that from the mesic habitat is large and greyish to black. 

 The following preliminary observations show quite pronounced differences 

 in the seed size from various localities. 



Mesic habitat Xeric and highly xeric habitats 

 South- North- 

 west west 



Murree Swat Swat Dir range nar Gilgit 



Average 



seed length 



(cm) 0.84 0.84 0.80 0.81 0.74 0.77 0.67 



Average 



seed breadth 



(cm) 0.50 0.S2 0.49 0.50 0.47 0.48 0.45 



Average No. 



of seeds 



per pound 6,960 6,430 7,425 6,210 9,360 8,000 10,080 



Observations recorded for needle length of the few localities 

 covered so far again indicate that drier localities (Parachinar, Gilgit, 

 Sulaiman range, Dir) have shorter needles and the moister localities have 

 longer needles . 



Sulai- 





man 



Parachi- 



range 



nar 



South- 



Para- 



east 



chinar 



Swat 



(Speena 



(Beha) 



shaga) 







North- 



Sulai- 





west 



man 



Dir 



Swat 



range 



(Patrak) 



(Atror) 



Gilgit 



Average 



needle 



length 



(cm) 14 11 12.2 12.5 13 13.3 



SUSCEPTIBILITY TO PHYSICAL AND BIOLOGICAL INJURIES 



Blue pine suffers from snow more than any other conifer of West 

 Pakistan. The snow clings to the crown, either causing top breakage or 



