**2. Production and constraints**

In the global lentil scenario, India ranked first in the area and second in the production with 39% and 22% of world area and production respectively. Canada ranking first in production (41.2%). The highest yield is recorded in Croatia (0.3 tons per ha) followed by New Zealand (0.25 tons per ha) [5] (**Table 1**).

Fusarium wilt epidemics depend on crop stages (seedling or adult flowering), environment and crop variety [20, 21]. Fusarium wilt is part of a disease complex under field conditions. In India, 12 fungal pathogens were identified where *Fol* is the dominant pathogen (30.8%), followed by *Rhizoctonia bataticola* (17.5%) and *Sclerotium rolfsii* (15.7%) [22]. The prevalence of wilt-root rot complex and their associated pathogens were reported by Chaudhary et al. (2010) from India and the main pathogens associated with plant mortality were *Fusarium oxysporum* f.sp. *lentis* (62.0%), *Rhizoctonia bataticola* (25.2%) and *Sclerotium rolfsii* (9.8%) [23]. In India, under natural conditions wilt incidence can reach 50–78% [21, 24] and cause up to 100% yield loss if the crop is affected at the seedling stage [17]. In Czechoslovakia yield losses can reach as high as 70% [25]. In South and Northwest Syria disease incidence can reach up to 29% [26–29]. Moreover, field experiments indicated that the percentage seed yield loss per unit change in wilt incidence was 0.89 [30]. The disease incidence due to lentil wilt in Pakistan was recorded as 5–10% and may result in 100% crop loss under favorable conditions [31, 32]. Recently, the first report of *Fusarium nygamai* causing wilt disease on lentil in Pakistan is also reported [33]. Presence of the nematode significantly increased Fusarium wilt incidence. It causes significant reduction in shoot length, root length and nodulation in both susceptible and resistant cultivars [34].

**Table 1.** Global ranking in area, production and yield: (area—million hectare, production—million tons, yield—tons/

World 4.52 World 4.83 World 0.107

**Rank Area Production Yield**

**Country Area % to world Country Prod % to world Country Yield**

Fusarium Wilt: A Killer Disease of Lentil http://dx.doi.org/10.5772/intechopen.72508 121

 India 1.80 39.8% Canada 1.99 41.2% Croatia 0.286 Canada 1.22 26.9% India 1.10 22.8% New Zealand 0.247 Turkey 0.24 5.4% Turkey 0.35 7.1% Armenia 0.226 Nepal 0.21 4.6% Australia 0.24 4.9% China 0.208 Iran 0.17 3.7% Nepal 0.23 4.7% Egypt 0.206 Australia 0.16 3.6% Bangladesh 0.16 3.3% Canada 0.163 Bangladesh 0.12 2.8% USA 0.16 3.2% Iraq 0.157 Syria 0.11 2.5% Ethiopia 0.14 2.8% USA 0.149 U.S.A 0.10 2.3% China 0.13 2.6% Australia 0.147 Ethiopia 0.10 2.2% Iran 0.08 1.8% Lebanon 0.146

*Fusarium oxysporum* is a pathogenic fungus commonly found around the world. It is a soil borne ascomycete causing Fusarium wilt, on many economically important crops. The pathogen comprises of over 120 known strains and each of which is specific to unique host plant in which it causes disease. *F. oxysporum* strains infect and kills many commercially harvested crops and

**3. Fusarium wilt pathogen**

Source: FAOSTAT 2015

hectare).

http://faostat3.fao.org/home/index.html

In many countries, lentil is cultivated as a rainfed crop and affected by several biotic (fungi, viruses, nematodes, insect pests and parasitic plants) and abiotic stresses (terminal drought, heat stress, cold, waterlogging and low soil fertility). Biotic stresses caused by pathogenic fungi include Fusarium wilt (*Fusarium oxysporum* f.sp. *lentis: Fol*), Ascochyta blight (*Ascochyta lentis*), Anthracnose (*Colletotrichum truncatum*), Stemphylium blight (*Stemphylium botryosum*), Rust (*Uromyces viciae-fabae*), Collar rot (*Sclerotiun rolfsii*), Root rot (*Rhizoctonia solani*), and Botrytis gray mold (*Botrytis cinerea*) [12, 13]. It is also known that lentil is susceptible to several species of *Orobanche* and *Phelipanche* prevalent in the Mediterranean region [14]. Till now, only *F. oxysporum* f.sp. *lentis* has been reported as the cause of Fusarium wilt of lentil but recently *F. redolens* was found associated with lentil wilt in Italy [15].

Among the biotic stresses, Fusarium wilt is a serious disease in reducing lentil yield in India, West Asia, North Africa and East Africa [16]. Fusarium wilt can cause yield losses up to 50% of the production to complete yield loss if severely affected. The disease appears at seedling stage (early wilt) or during the reproductive stage (late wilt) [17, 18]. The pathogen can survive in the soil as chlamydospores which can remain viable for many years [19] making crop rotation as a control option ineffective.


http://faostat3.fao.org/home/index.html

seeded (microsperma) and large seeded (macrosperma) [6]. Lentil is recognized as one of the most nutritious pulse crops ranking next to chickpea among cool-season food legumes. It contains 57–60% carbohydrate, 24–26% protein, 3.2% and 1.3% fiber. It is also a rich source of minerals containing calcium (69 mg per 100 g), phosphorus (300 mg per 100 g) and Iron (7 mg per 100 g) of seed [7, 8]. Lentil seed contains lysine, an essential amino acid, found only at low levels in cereal protein. Lentil is a valuable human food, mostly consumed as dry seeds as well as used as fodder, and generally grown as a crop rotation after cereals to enrich the soil by their nitrogen fixing ability [9]. In South East Asia, lentil mostly grows on residual soil moisture after post rainy season under rainfed conditions. The inclusion of lentil as a crop rotation can benefits the succeeding crops by improving the soil health through biological nitrogen fixation and carbon sequestration. The amount of nitrogen fixed by plants varies from 0 to 192 kg total N/ha around a mean of 80 kg total N/ha [10]. This estimate of N fixation is similar

120 Fusarium - Plant Diseases, Pathogen Diversity, Genetic Diversity, Resistance and Molecular Markers

Since 1970s there have been significant achievements in national and international lentil programs in developing phenologically adapted, stress resistant and high-yielding cultivars [11]. During the past three decades, different national agricultural systems released more than 90 improved cultivars from germplasm developed by the International Centre for Agricultural Research in the Dry Areas (ICARDA) [11]. Therefore, the current review covers past achievements in managing the disease, pathogen diversity and identify gaps in managing Fusarium

In the global lentil scenario, India ranked first in the area and second in the production with 39% and 22% of world area and production respectively. Canada ranking first in production (41.2%). The highest yield is recorded in Croatia (0.3 tons per ha) followed by New Zealand

In many countries, lentil is cultivated as a rainfed crop and affected by several biotic (fungi, viruses, nematodes, insect pests and parasitic plants) and abiotic stresses (terminal drought, heat stress, cold, waterlogging and low soil fertility). Biotic stresses caused by pathogenic fungi include Fusarium wilt (*Fusarium oxysporum* f.sp. *lentis: Fol*), Ascochyta blight (*Ascochyta lentis*), Anthracnose (*Colletotrichum truncatum*), Stemphylium blight (*Stemphylium botryosum*), Rust (*Uromyces viciae-fabae*), Collar rot (*Sclerotiun rolfsii*), Root rot (*Rhizoctonia solani*), and Botrytis gray mold (*Botrytis cinerea*) [12, 13]. It is also known that lentil is susceptible to several species of *Orobanche* and *Phelipanche* prevalent in the Mediterranean region [14]. Till now, only *F. oxysporum* f.sp. *lentis* has been reported as the cause of Fusarium wilt of lentil but

Among the biotic stresses, Fusarium wilt is a serious disease in reducing lentil yield in India, West Asia, North Africa and East Africa [16]. Fusarium wilt can cause yield losses up to 50% of the production to complete yield loss if severely affected. The disease appears at seedling stage (early wilt) or during the reproductive stage (late wilt) [17, 18]. The pathogen can survive in the soil as chlamydospores which can remain viable for many years [19] making crop

to the quantities fixed by chickpea and dry bean.

wilt to improve productivity and production of the crop.

recently *F. redolens* was found associated with lentil wilt in Italy [15].

**2. Production and constraints**

(0.25 tons per ha) [5] (**Table 1**).

rotation as a control option ineffective.

**Table 1.** Global ranking in area, production and yield: (area—million hectare, production—million tons, yield—tons/ hectare).

Fusarium wilt epidemics depend on crop stages (seedling or adult flowering), environment and crop variety [20, 21]. Fusarium wilt is part of a disease complex under field conditions. In India, 12 fungal pathogens were identified where *Fol* is the dominant pathogen (30.8%), followed by *Rhizoctonia bataticola* (17.5%) and *Sclerotium rolfsii* (15.7%) [22]. The prevalence of wilt-root rot complex and their associated pathogens were reported by Chaudhary et al. (2010) from India and the main pathogens associated with plant mortality were *Fusarium oxysporum* f.sp. *lentis* (62.0%), *Rhizoctonia bataticola* (25.2%) and *Sclerotium rolfsii* (9.8%) [23]. In India, under natural conditions wilt incidence can reach 50–78% [21, 24] and cause up to 100% yield loss if the crop is affected at the seedling stage [17]. In Czechoslovakia yield losses can reach as high as 70% [25]. In South and Northwest Syria disease incidence can reach up to 29% [26–29]. Moreover, field experiments indicated that the percentage seed yield loss per unit change in wilt incidence was 0.89 [30]. The disease incidence due to lentil wilt in Pakistan was recorded as 5–10% and may result in 100% crop loss under favorable conditions [31, 32]. Recently, the first report of *Fusarium nygamai* causing wilt disease on lentil in Pakistan is also reported [33]. Presence of the nematode significantly increased Fusarium wilt incidence. It causes significant reduction in shoot length, root length and nodulation in both susceptible and resistant cultivars [34].
