Using host plant resistance to manage biotic stresses in cool season food legumes

Research paper by F. J. Muehlbauer, W. J. Kaiser

Indexed on: 01 Jan '93Published on: 01 Jan '93Published in: Euphytica


The cool season food legumes are seriously affected by diseases and pests that collectively cause yield reductions variously estimated at over 50% on a world wide basis. The use of host plant resistance to increase and stabilize yields depends on a well planned plant breeding program, i.e., germplasm evaluation, hybridization with otherwise adapted material, and screening and selection methods that efficiently identify segregants with combined resistance to multiple diseases and insect pests. Sequential and simultaneous screening has successfully combined resistance to Ascochyta blight and Fusarium wilt of chickpea; Fusarium wilt, powdery mildew, and viruses of pea; and Fusarium wilt and rust of lentil.Resistance has generally been durable for the soilborne diseases; however, resistance to Ascochyta blight has often been overcome by new pathotypes. Resistance to powdery mildew, pea enation mosaic and other viruses has been durable. Some of the most serious biotic stresses of the cool season food legumes remain as chronic production constraints. These include Aphanomyces root rot of pea, rust and Ascochyta blight of lentil, root rot of chickpea, chocolate spot of faba bean, and Orobanche ssp. that parasitize all of the cool season food legumes.The use of host plant resistance to control insect pests is almost non-existent; however, resistance to Heliocoverpa and leaf miner of chickpea has been identified and work is underway toward developing resistant cultivars. The control of Bruchus spp. and Sitona spp. through host plant resistance remains as a remote possibility.Cultivars which are resistant or tolerant to one or more biotic stresses are a critical component of integrated pest management. Decisions as to crop rotations, monitoring of field populations of pathogens or insects, pesticides or biological control agents, tillage, planting dates, method of planting, and other factors can all be critical to reducing the effects of biotic stresses. Successful production of cool season food legumes appears to depend on the creation of cultivars with genetic resistance to one or more pests followed by management decisions designed to delay development of pathotypes or biotypes capable of overcoming the available resistance.