Start codon targeted (SCoT) polymorphism-based genetic relationships and diversity among populations of Tecomella undulata (Sm.) Seem-an endangered timber tree of hot arid regions

Tecomella undulata (Sm.) Seem commonly called Rohida or Desert teak (family bignoniaceae) is an important agroforestry tree having an important pharmacological and therapeutic uses. Its distribution is restricted to hot arid regions of India and Pakistan having < 150 to 500 mm annual rainfall. Genetic diversity status of this important endangered timber tree species designated state flower of Rajasthan remains unrevealed. Genetic diversity of 21 populations (108 accessions) encompassing yellow, red and orange coloured flower bearing morphotypes collected from all 12 districts of western Rajasthan, India, has been examined using start codon targeted (SCoT) polymorphism for the first time. Fingerprinting with 22 SCoT primers (out of 36 screened) generated 294 amplicons of 100 to 3000 bp size, of which 212 (71.6%) were polymorphic. Amplicon number varied from 4 (SCoT-9) to 24 (SCoT-15) with an average of 13.4 amplicons per primer. Average polymorphism information content (PIC), Nei's diversity index (H) and Shannon index (I) were 0.54, 0.22 and 0.36, respectively. Dendrogram generated using unweighted pair-group method with arithmetic mean (UPGMA) delineated the 108 accessions into 5 clusters while 2 accessions out grouped. Principal coordinate analysis (PCoA) also revealed similar clustering. High level of genetic differentiation among accessions/populations was attributed to cross pollination and continuous evolution under harsh agro-climatic conditions.