Submitted to: International Chickpea and Pigeonpea Newsletter
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 1, 2004
Publication Date: August 1, 2004
Citation: Chen, W., Mcphee, K.E., Muehlbauer, F.J. 2004. Use of grafting top study chickpea resistance to ascochyta blight. International Chickpea and Pigeonpea Newsletter. 11:39-41. Interpretive Summary: Resistance to Ascochyta blight in chickpea has been an important tool for managing Ascochyta blight. However, the mechnisms of resistance are not well understood. This study was carried to detect any disease-mediating agents in chickpea that are translocated between resistant and susceptible chickpea genotypes. Reciprocal grafting between resistant and susceptible chickpeas followed by inoculation with A. rabiei showed that the rootstock had no detectable contribution to the disease phenotype of the shoots (scions), and the disease phenotypes was conditioned locally by the scion genotypes. No movement of any disease-mediating agents across the graft junction was detected using the disease bioassay.
Technical Abstract: Ascochyta blight caused by Ascochyta rabiei is an important disease of chickpea. The pathogen is known to produce several phytotoxins. Reciprocal grafting between resistant and susceptible chickpea genotypes was employed to elucidate possible mechanisms of resistance by detecting translocations of disease-mediating agents such as toxin receptors or detoxifying enzymes across the graft junction. Chickpea genotypes Dwelley and Spanish White were grafted reciprocally and self-graft, and inoculated with isolates of either pathotype I or pathotype II of A. rabiei. Results showed that the scions of a given genotype grafted onto either resistant or susceptible genotype rootstocks reacted similarly to infection by A. rabiei. The genotype of the rootstock showed no detectable effect on the disease phenotype of the scion. The disease phenotype is conditioned locally by the scion genotype.