Teak population structure and genetic diversity in Gujarat, India

The teak (Tectona grandis L.) is forest tree, has a diploid chromosome number 2 n = 2x= 36. Farmers grow teak wood for commercial purposes since it is one of the most valuable tropical timbers. Therefore, modern approaches for studying the diversity of outstanding teak have shifted their emphasis to enhancements and conservation. In this instance, 134 teak samples from 14 populations were collected from various locations in Gujarat state of India. A total of 65 SSR primers were tested for diversity; 23 primers with distinct and clear bands were chosen for further investigation. All populations were grouped into three main clades based on SSR data with some admixture. The mean value of the observed alleles was 18, ranging from 11 to 29. The PIC values for SSRs 16 and 2 were respectively 0.95 and 0.82, with an average of 0.89. SSR 62 had the highest expected heterozygosity of 0.88, while SSR 16 had the lowest expected heterozygosity of 0.97, with a mean value of 0.94. SSR 22 had the largest gene flow, 0.73 and SSR 62 had the lowest gene flow, 0.13, with a mean value of 0.35. Nei's genetic diversity averaged 0.90, with SSR 16 having the highest value (0.95) and SSR 2 having the lowest (0.84). Dendrogram based on Nei's genetic diversity classified all 14 populations into three major clusters. The cluster I consisted of eight populations: Ranipura, Shivrajpur, Jambughoda, Ukai, Vansda, Sabarkantha, Junagadh and Girnar. Cluster II contained only one Achhala population, which was the most diverse of all the populations. Cluster III was composed of the five populations of Anand, Rajpipla, Valsad, Bharuch and Godhara. The data led to the conclusion that SSR maker would be the best alternative for population structure and marker-assisted selection as compared to RAPD and ISSR because it showed 100 % polymorphism and a high PIC value, indicating its capacity to differentiate between distinct populations. Based on these findings the diverse populations may be preserved by in situ conservation, and genetic advancement will be supported by population variety.