Identifying sources of resistance in chickpea to seed rot and seedling damping‐off caused by metalaxyl‐resistant Pythium ultimum

Abstract

AbstractChickpea (Cicer arietinum L.) has been a globally important source of nutrition for human and animal diets for several thousand years. In the United States, chickpeas are integral components of dryland agriculture systems throughout the Pacific Northwest and Northern Plains, but seed rot and preemergent damping‐off of chickpea caused by metalaxyl‐resistant isolates of Pythium ultimum Trow have emerged as diseases of increasing importance in the U.S. Pacific Northwest. The objective of this study was to identify sources of resistance to metalaxyl‐resistant P. ultimum in chickpea. Resistance was evaluated based on the emergence of chickpea seedlings from soil artificially infested with the pathogen. Significant differences in emergence were consistently detected between the desi chickpea cultivar ‘Myles’ and the kabuli chickpea cultivar ‘Sierra’. These two cultivars were used as checks to screen two different chickpea mini‐core collections, including a 39‐accession mini‐core collection from the U.S. National Plant Germplasm System and 209 accessions from a chickpea mini‐core collection developed by International Crops Research Institute for the Semi‐Arid Tropics (ICRISAT). A total of 194 desi accessions and 41 kabuli accessions were significantly more resistant than Sierra, whereas 85 desi accessions identified from the ICRISAT collection were highly resistant to both P. ultimum isolates. Accessions with pigmented seed coats were significantly more resistant than accessions with beige seed coats, which is a characteristic of kabuli chickpeas. Two accessions, W6 25882 and W6 25884, may be especially promising parental materials for improving kabuli cultivars based on their consistent resistant reactions to P. ultimum isolates and higher 100‐seed weight.