Sources of resistance in chickpea (Cicer arietinumL.) to ascochyta blight (Ascochyta rabiei)

Abstract

Ascochyta blight is the major biotic stress that causes significant yield losses in chickpea (Cicer arietinum L.) all over the world. The disease is caused by the fungus Ascochyta rabiei (Pass.) Lab (telemorph Dydimella rabiei = Mycosphaerella rabiei (Kovachevski) v. Arx. The use of resistant cultivars is widely acknowledged as the most economic and environmentally friendly method for disease control. The aim of this study is to screen chickpea cultivars and lines for resistance to ascochyta blight with a view for using them in a breeding program. The investigations were carried out during 2012-2017 in Dobroudzha Agricultural Institute (DAI)-General Toshevo. Twenty chickpea accessions were inoculated under field and greenhouse conditions with 30 Ascochyta rabiei isolates. Disease reaction was estimated after 14 days by using 9-degree scale. Disease incidence (DI) was calculated according to the Mc Kinney index. Cluster analysis was used to group the accessions and isolates according to the DI. Nine accessions showed middle resistance under field conditions during the three years of investigations. No immune or resistant accession to all 30 isolates was found under greenhouse conditions. The cluster analysis grouped the accessions into two major classes. One of the classes consists of two accessions (XOOC01CA0490B0223D and XOOC01CA0490B2140D) which showed middle resistance to 12 and 13 of the isolates, respectively. The cluster analysis grouped the isolates into classes, subclasses and sub sub classes according to their virulence to the 20 chickpea accessions. The highest virulence showed five isolates (AR 883, AR 061, AR R1, AR 1013, AR 1015) with DI from 5.40 to 9.00 in all accessions. Differences in field and greenhouse results were expected and they were due to the strong dependence of disease development to climatic conditions. The results in this investigation showed that two chickpea accessions can be used in a breeding program for ascochyta blight resistance.