Mortality in Dalbergia sissoo (Roxb.) following heavy infection by Aristobia horridula (Hope) Bettles: will genetic variation in susceptibility play a role in combating declining health?

Genetic variation in mortality was studied by comparing survival of 70 progenies of Dalbergia sissoo originating from different parts of Nepal. The analysis was based on their performance in a so-called seedling seed orchard (SSO) that was heavily infested by Aristobia horridula ; a beetle that has become a severe pest infesting and killing young trees in sissoo plantings. Large and highly significant differences were found between families in mortality, showing that some progenies seem to resist the attack much better than others. Although dealing only with resistance against the beetle attachment, the results awaken hope that phenotypic selection in tree improvement programmes can be an important tool in tackling the general health problems in sissoo plantations. This calls for special interest in the dieback syndrome that has seriously decreased health of sissoo planting in Nepal, Pakistan and India.