Resistance to Six Races of Ascochyta rabiei in the World Germplasm Collection of Chickpea

Abstract

Ascochyta blight [caused by Phoma rabiei (Pass.) Khune & J.N. Kapoor; syn. Ascochyta rabiei (Pass.) Lab.] is the most important disease of chickpea (Cicer arietinum L.) in many countries. Progress in breeding blight‐resistant cultivars has been hampered by the absence of dependable sources of resistance. An effort was made to screen the world germplasm collection against races of P. rabiei with the objective of identifying resistant sources. A total of 19 343 germplasm accessions of chickpea (12 749 desi and 6594 kabuli types) were evaluated for resistance to six races of P. rabiei at Tel Hadya, Syria, between 1979 and 1991. Germplasm accessions were sown in the field during the winter season and inoculated by scattering ascochyta blightdiseased chickpea debris and spraying a spore suspension of a mixture of six races of P. rabiei prevalent in Syria and Lebanon. In greenhouse evaluations, germplasm accessions were grown in pots and inoculated by spraying the spore suspension of a composite of the six races; inoculated plants were incubated in plastic moist chambers for 1 wk. Blight severity was scored on a scale of 1 to 9, where 1 to 4 = resistant, 5 = tolerant, and 6 to 9 = susceptible. Only three desi accessions (ICC 4475, ICC 6328, and ICC 12004) and two kabuli accessions (ILC 200 and ILC 6482) were resistant in repeated field and greenhouse evaluations. Another six desi and three kabuli accessions were resistant in repeated Held tests but tolerant in greenhouse evaluations. These accessions will be used as sources of resistance in the ascochyta blight‐resistance breeding programs.