RAPD markers for screening shoot gall maker (Betousa stylophora Swinhoe) tolerant genotypes of amla (Phyllanthus emblica L.)

Phyllanthus emblica Linn. is the most important medicinally useful tree crop in Asian Subcontinent and is severely infested by Betousa stylophora Swinhoe, known as shoot gall maker (SGM). This pest tunnels the shoots of seedlings and actively growing branches of trees and develops gall, leading to stunted growth, unusual branching and death of actively growing shoots. Our study revealed that trees possessing smooth bark were free from the attack of this pest than those with rough bark surface. Unfortunately, this character is not detectable either at seedling stage or during early growth of trees in the orchard. RAPD genetic fingerprinting of trees possessing smooth and rough bark revealed distinguishable and highly reproducible DNA banding pattern between the two genotypes. Of the 20 RAPD primers tested, five of them produced distinguishable RAPD bands between rough and smooth barked genotypes of P. emblica. Trees with smooth bark produced five unique RAPD bands with molecular weight ranging from 350 bp to 1500 bp and those with rough bark produced six RAPD bands (350 bp-650 bp) to utilize these DNA bands as potential DNA marker for screening tolerant genotypes of this crop against SGM. The utility of this finding in genetic improvement of this tree crop against SGM is discussed.