Morphological, anatomical and molecular characterization of full-sib pseudo-F₂ (F₁) progenies in mulberry with resistance to bacterial leaf spot (Xanthomonas campestris pv. mori)

Bacterial leaf spot (BLS), caused by Xanthomonas campestris pv. mori is a devastating foliar disease of mulberry. Full-sib progenies descendent from control cross between BLS resistant source ‘Morus rotundiloba’ and susceptible commercial cultivar ‘S-1’ were evaluated for BLS disease reaction. The continuous population distribution of BLS disease severity (DSI) across the progenies indicated additive nature of the resistant trait. Besides, morphological and anatomical characterization of the selected resistant and susceptible progenies showed high significant positive correlation between DSI and stomata frequency. Significant negative correlation of DSI was observed with leaf thickness, thickness of upper epidermis and upper cuticle layers. RAPD profiling with Genei primer 17 and 18 generated two unique DNA fragments of 500bp and 450bp for five each of resistance and susceptible progenies, respectively. The dendrogram using the binary statistic of RAPD analysis exhibited distant relationship between the parents as well as resistant and susceptible progeny groups.