Seed source variation and conservation of Pinus wallichiana in India

Abstract

Pinus wallichiana A.B. Jacks is an important component of the middle and high altitude Himalayan forests having large natural distribution ranging between 260 to 360 N latitude and 690 to 750 E longitudes. It is commonly known as Himalayan blue pine or blue pine, being indigenous to Himalayan Mountain regions and because of its bluish or grayish-green leaves. It is a five needle pine which gained world-wide attention for its resistance to blister rust among white pines. This species has been crossed successfully with other white pines and vigorous hybrids have been obtained. Considerable variation in morphological and anatomical characteristics of needles, cones and seeds in natural stands exists across the natural distribution of the species, especially in mesic and xeric habitats. These variations suggested the differentiation of this species in ecotypes or varieties as reported by various authors. However, the level of genetic diversity was found to be relatively high and the degree of genetic differentiation was low compared to other pines. The wide range of climatic conditions in the natural distribution of this pine is expected to result in high genetic variation within different populations of the species. The study aims to determine the nature and extent of variation present in the populations of the species in respect to cone and seed characteristics across its natural distribution. Seed of 17 seed sources from the states of Uttaranchal and Himachal Pradesh was collected and analyzed for cone characters (fresh weight of cones, cone length, cone width, specific gravity) and seed characters (seed weight, moisture content, germination percent, cotyledon number). Significant variations have been observed in these traits among different seed sources of the species. The cone weight varied from 44.4 to114g and the higher cone weight was recorded at higher altitudes. The germination percent varied from 40 to 85 whereas cotyledon number varied from 7 to12. Seed weight ranged from 35.70 to 69.30g in all seed sources. These variations can be utilized further in identifying the best seed sources in improving the productivity of the species. The genetic variability present in this pine has been conserved in preservation plots demarcated and maintained in its natural ranges of distribution in the country, since the early 19th century.