Assessing the resistance to root-lesion nematode (Pratylenchus thornei) in a new collection of wild chickpea (Cicer reticulatum and c. Echinospermum) from Turkey

Assessing the resistance to root-lesion nematode (Pratylenchus thornei) in a new collection of wild chickpea (Cicer reticulatum and c. Echinospermum) from Turkey

Chickpea (Cicer arietinum L.) is an ancient grain legume first domesticated some 10,000 years ago and is now the second major pulse produced worldwide. The rootlesion nematode Pratylenchus thornei is a microscopic eelworm, and is the foremost nematode species affecting chickpea production worldwide with yield losses of intolerant Australian cultivars estimated to be up to 25%. Crop improvement has been challenged by the narrow genetic diversity within cultivated chickpea and a previously limited world collection of wild chickpea. Crop wild relatives are a rich source of genetic diversity for new allelic variation including disease resistance, and thereby play a major role in meeting challenges for 21st century agriculture. Recent collection missions in southeastern Turkey have boosted numbers of accessions of wild chickpea, namely C. reticulatum Ladizinsky and C. echinospermum P. H. Davis, the only wild species crossable with the cultigen C. arietinum. This study evaluated 174 accessions (133 C. reticulatum and 41 C. echinospermum) under controlled-environment conditions to identify levels of P. thornei resistance within the collection. Assessments were determined at chickpea species level, with geographic locations and genetic population groups also assessed to identify any clusters of resistance.

Accessions of both wild Cicer species were, on average, more resistant (P < 0.001) than the cultigen C. arietinum. Multi-environment analyses to determine genetic rankings of accessions showed 53 (30%) accessions were significantly more resistant than the least susceptible Australian cultivar PBA Seamer. Collection sites and genetic population groups differed significantly (P < 0.001) for mean P. thornei population densities. This is the first study to evaluate nematode resistance of this new collection and it has revealed novel sources of P. thornei resistance that can be exploited by breeding programs worldwide for chickpea improvement. Furthermore, the study provides valuable quantitative information for future genetic studies to identify candidate genes for P. thornei resistance in chickpea.