Identification of resistant source in lentil germplasm against Fusarium wilt in relation to environmental factors

Lentil is a valuable human food and one of the oldest known protein rich food legumes which is also known as poor men’s meat. Owing to biotic and abiotic stresses, the crop yield is below attainable levels which are mainly attributed to pathological factors especially lentil wilt caused by Fusarium oxysporum f.sp. lentis. It is a potential threat to lentil production not only in Pakistan but worldwide as well that can cause complete crop failure. Current studies were designed to screen the available lentil germplasm against the lentil wilt disease in relation to environmental factors. Twenty eight lentil lines were sown in a previously developed wilt sick bed in the research area of Pulses Research institute, Faisalabad using augmented design. Natural inoculum was also relied upon. Disease severity data were recorded and area under disease progress curve was calculated. Results revealed that sixteen lines were found highly susceptible, seven remained susceptible, and three lines were moderately resistant whereas two demonstrated resistance responses against the disease. Furthermore, disease severity data along with weekly environmental conditions were subjected to correlation and stepwise regression analysis to screen environmental variables not having a significant influence on lentil wilt development. All the environmental factors were positively correlated with disease development and best explained using linear regression. Maximum disease severity was recorded at 17-18 o C and 7-10 o C air temperature (Max. and Min.), 60-78% relative humidity and 2 mm rainfall respectively. Stepwise regression employed to predict lentil wilt incidence, the model developed significantly fit to the data and their predicted values of lentil wilt incidence were in close conformity with the observed values.