Microsatellite Analysis to Study Genetic Diversity in Khasi Pine (Pinus Kesiya Royle Ex. Gordon) Using Chloroplast SSR Markers

Pinus kesiya (Khasi pine) is the principal pine species in northeast India having high commercial value. Chloroplast microsatellites (cpSSR) were used to study the genetic diversity and population genetic structure of 10 populations of P. kesiya covering entire natural range of distribution in India. A total of 33 primer pairs (cpSSRs) of P. thunberghii and P. sylvestris were tested in P. kesiya for their transferability, out of which 18 chlo­roplast primers showed positive amplification and 10 were found polymorphic. A total of 250 individuals from 10 different populations were genotyped using the selected 10 cpSSRs. When alleles at each of the 10 loci were jointly analysed a total of 36 size variants were discovered, which combined to desig­nate 90 haplotypes among 250 individuals. None of the haplo­type was found common among the populations as they were population specific. The cpSSR indicated that P. kesiya popula­tions have maintained a moderately high genetic diversity (HT=0.638) which is typical in most coniferous species. Howe­ver, the inter-population genetic diversity was higher than the intra population diversity and the genetic differentiation bet­ween populations was also found to be very high (FST=0.47). A Bayesian cluster analysis separated the populations into six clusters where most of the individuals were found in single population clusters with minor admixtures. The distribution of genetic diversity and sub structuring of P. kesiya reflect week pollen mediated gene flow due to geographic isolation and genetic drift. The study has revealed useful cpSSR markers for P. kesiya, which were lacking earlier and also added an insight into the state of Khasi pine forest in the region, which can be useful for the better management and future conservation programs.

Genetic Diversity Assessment of Khasi pine (Pinus kesiya Royle ex. Gordon) from Meghalaya Using Chloroplast Microsatellite Markers

The study conducted on four populations of P. kesiya using cpSSR markers reported that the overall genetic diversity was higher (HT=0.547) as compared to within population genetic diversity (HS=0.285). Gene flow estimate was found to be relatively low (Nm=0.543). The analysis of molecular variance (AMOVA) revealed 51.09% of the variation to be within population and 48.91% of the variation to be among populations. UPGMA clustering segregated the populations into a single cluster and the identity matrix showed that the population from Jowai was genetically distinct and requires special attention. The study highlighted sufficient levels of genetic variation among the populations of this region which should be conserved. Information obtained from this study can be useful in setting up proper management strategies for the conservation of P. kesiya forest in Northeast India.

Distribution of ectomycorrhizal fungi in pure stands of different age groups of Pinus kesiya

A study on ectomycorrhizae and mycorrhizal fungi of Pinus kesiya (Royle ex Gordon) in 2-, 4-, 11-, and 17-year-old pine plantations was carried out. Thirteen mycorrhizal fungi forming ectomycorrhiza with khasi pine were observed. Diversity index of mycorrhizal fungi was directly proportional to the age of the pine stand. The maximum number of fungal species was observed in the oldest stand. Evenness of the sheathing mycorrhizal fungi was also increased with the increase in age of pine. The sporocarps of Boletus luteus, Scleroderma aurantium, Tricholoma saponaceum, and Hygrophorus limacinus were observed as an early colonizing fungi with Pinus kesiya. However, in older plantations Russula lepida and Amanita phalloides were observed as late stage fungi. Boletus luteus and Scleroderma aurantium were dominant species in all the pine stands. Sporocarps of mycorrhizal fungi were maximum during the rainy season and minimum during the winter months. A positive correlation was observed between the number of ectomycorrhizae and mycorrhizal infection with soil moisture, soil pH, total nitrogen, available phosphorus, exchangeable potassium, and organic matter of the soil. The number of sporocarps exhibited a positive significant correlation with soil moisture content in all the plantations.Key words: ectomycorrhiza, fungi, physicochemical characters, Pinus kesiya.