Nematode and fungal diseases of food legumes under conservation cropping systems in northern Syria

Abstract

Conservation agriculture is becoming popular due to its potential for enhanced productivity and cost savings among small scale farmers in developing countries. The International Center for Agricultural Research in Dry Areas is promoting conservation cropping systems that involve cereal-legume rotation in West Asia and North Africa region. Studies were made on the impact of long-term rotation trial on diseases of chickpea and lentil as well as the evaluations of lentil genotypes for their reactions to Fusarium wilt and downy mildew under two tillage practices. In the long-term rotation trials, the two season results showed no significant differences between tillage practices, crops and planting dates and their interactions in affecting mean percent cyst nematode disease. The mean cyst nematode disease incidence ranged from 7.3% on early planted lentil on CT to 14.5% in late planted chickpea on ZT. Tillage practices significantly (P <= 0.05) affected Ascochyta blight incidence but not its severity. The incidence ranged from 4% to 22.5% under early planted chickpea on both tillage practices. Moreover, the mean severity ranged from 3.2 to 5.5 rating in early planted CT and ZT, respectively. The combined analysis showed significant differences (P <= 0.05) among genotypes but not their interactions with tillage for Fusarium wilt and downy mildew reactions. All the genotypes showed less than 10% Fusarium wilt mortality indicating high levels of resistance. The mean downy mildew severity ranged from 1.3 in ILL7991 to 2.6 rating in ILL6994. This study showed that both soil borne and foliar diseases could be a problem in conservation cropping system and continuous monitoring of diseases is essential to prioritize management practices in relation to conservation agriculture in Mediterranean type environments. Moreover, cool-season legume genotypes with disease resistance and high yield can be developed under conservation agriculture that could also serve traditionally tilled production systems. (C) 2012 Elsevier B.V. All rights reserved.