Evaluation of lentil cultivars and lines for resistance to Fusarium oxysporumf.sp. lentis

Abstract

Editors and Sections Genetics and Breeding Atanas Atanasov (Bulgaria)Svetlana IntroductionLentil (Lens culinaris Medik.) is one of the most important food legume crops in the farming and food systems of many countries, including Bulgaria. In recent years lentil fields increased in our country. The productivity of lentil is affected by a number of biotic and abiotic stresses of which Fusarium wilt (Fusarium oxysporum f.sp. lentis-Fol) is the most important yield-limiting factor (Bayaa et al., 1997;Mohammadi et al., 2012;Pouralibaba et al., 2016; Al-Husien et al., 2017). Fusarium wilt occurs during seedling and reproductive stages of the crop and can cause up to 100% yield losses under favorable conditions for disease development (Khare, 1981). Disease symptoms include stunting, wilting, marked reduction of root system, and internal vascular discoloration of the lower stem (Tosi and Cappelli, 2001). Management practices for disease control include long-term crop rotation with nonsusceptible hosts and removal and destruction of infected crop debris (Tosi and Cappelli, 2001). Seed treatment with carbendazim, captan (Maheshwari et al., 2008), benzimidazoles and tiram (Tosi and Cappelli, 2001) can reduce disease incidence and plant mortality. Breeding resistant cultivars is the major approach to control the disease and many resistant lines and cultivars are released in different countries (Pandya et al., 1980;Mihov et al., 1987; Bayaa et al. 1997; El-Ashkar et al. 2004;Mohammadi et al., 2012). Sources of resistance to wilt have been found in the cultivated lentil (Bayaa and Erskine, 1990;Mohammadi et al., 2012;Pouralibaba et al., 2016) and lentil wild relatives (Bayaa et al., 1995). Resistance of lentil to Fol is controlled by major genes (Eujayl et al., 1998). For many years, it was believed that no races/pathotypes are existing in the Fol population (Bayaa et al., 1997), but pathogenic and genetic variability of the pathogen has been reported from Algeria, India and Iran (Belabid and Fortas, 2002; Belabid et al., 2004). In 2016 Pouralibaba et al. (2016) developed a differential set with four lentil accessions and identified seven Fol pathotypes.Fusarium wilt in Bulgaria is caused by Fol and Fusarium gibbosum but Fol has predominant distribution (Stanoeva, 2007). Cultural and pathogenic characteristics of the pathogens, the effect of the year, genotype and inoculum dose on the disease incidence (DI), and the reaction of lentil accessions to the pathogen under field condition have been investigated but no resistant varieties and breeding lines were found (Stanoeva, 2007). Since then systematic screening of the germplasm has not been undertaken.The aim of this investigation is to evaluate lentil cultivars and lines to Fol with a view to their use for breeding purposes. Material and methodsThe investigations were carried out during 2013-2015 at Dobrudzha Agricultural Institute, General Toshevo. Thirty two lentil accessions (14 cultivars and 18 lines) were sown in 1m rows in three replications. In every two rows, l...