Spatial distribution and epidemiology of chickpea wilt in major chickpea-growing regions of Maharashtra, India

Introduction

Chickpea (Cicer arietinum L.) is one of the most important pulse crops cultivated worldwide and is a valuable source of protein, carbohydrates, vitamins, and minerals, especially in developing countries (Jukanti et al., 2012) [9] . In addition to its nutritional value, chickpea improves soil fertility through biological nitrogen fixation, making it an important component of sustainable farming systems. India is the leading producer of chickpea, contributing nearly 65 percent of the global cultivated area and 68 percent of total production (Reddy and Mishra, 2010) [18] . Maharashtra is among the major chickpea-growing states in the country. Despite its importance, chickpea productivity is greatly affected by several diseases, among which Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceri, is one of the most serious. The disease is widespread across major chickpea-growing regions of the world and can cause yield losses ranging from 10-40 percent, reaching up to 100 percent under favourable conditions (Nene et al., 1984; Jalali and Chand, 1992) [12,6] . The pathogen survives in soil and seed for long periods and infects plants at different growth stages, resulting in yellowing, vascular discoloration, wilting, and eventual plant death (Pande et al., 2007; Jiménez-Fernández et al., 2011) [15,8] . In India, the incidence of Fusarium wilt varies with agro-climatic conditions, cropping practices, and pathogen populations (Singh et al., 2007; Dubey et al., 2010) [20,3] . Considering the importance of chickpea cultivation in Maharashtra and the potential impact of wilt disease, a systematic survey was undertaken to assess the incidence and distribution of Fusarium wilt in major chickpea-growing areas and to generate baseline information for future disease management and resistance breeding programmes.

Material and Method: Survey and Assessment of Wilt Incidence

A roving survey was conducted during the Rabi season (2021-2022) to assess the occurrence and distribution of chickpea wilt in major chickpea-growing areas of Maharashtra State. Efforts has been made to collect the wilt samples from 22 districts of Maharashtra and inspected for wilt disease incidence. The incidence of chickpea wilt was recorded based on the number of wilted plants observed in each field and expressed as percentage disease incidence using the following formula:

Wilt incidence (%) = Number of wilted plants X 100 Total number of plants observed Plants exhibiting typical wilt symptoms such as yellowing, drooping, vascular discoloration and complete wilting were collected from different surveyed locations in sterile paper bags and transported to the laboratory for further studies.

Isolation of the Pathogen

Wilted chickpea plants collected during the survey were used for isolation of the pathogen. Small pieces of infected root and stem tissues from the collar region were washed thoroughly under running tap water and surface sterilized with 1 percent sodium hypochlorite solution for 1-2 min, followed by three washings with sterile distilled water. The sterilized tissue bits were dried on sterile blotting paper and aseptically transferred onto Potato Dextrose Agar (PDA) medium plates. The inoculated plates were incubated at 27±2 °C for 5-7 days. Emerging fungal colonies were purified by hyphal tip/single spore isolation and maintained on PDA slants for further identification and studies.

Results and Discussion

The present investigation was conducted during 2020-25. The study evaluated that the occurrence of chickpea wilt, pathogen characterization, screening of antagonistic microorganisms, and efficacy of bioagents and pesticides under laboratory, pot culture, and field conditions. Their effects on wilt incidence, plant growth, and yield were assessed to develop effective integrated disease management strategies for chickpea wilt. A roving survey was conducted during the cropping season in twenty-two major chickpea growing districts of Maharashtra and assessed the incidence of chickpea wilt caused by Fusarium oxysporum f. sp. ciceris. In each district, five representative fields were selected, and wilt incidence was recorded based on the proportion of wiltaffected plants to the total number of plants observed at each location. (Table 1). The results clearly indicated substantial spatial variation in wilt incidence across the surveyed districts, ranging from 6.81 to 18.10 percent, confirming that chickpea wilt is endemic but unevenly distributed across the state. Similar spatial heterogeneity in wilt distribution has been reported earlier by Nikam et al., (2011) [14] and Sontakke et al., (2020) [21] in different chickpea-growing regions of Maharashtra. Among all the districts, the highest wilt incidence i.e. (18.10%) was recorded in Akola district, followed by Parbhani (17.32%), Dharashiv (17.07%), Amaravati (16.89%), Hingoli (16.46%) and Jalna (16.29%). These districts represent major chickpea production belts characterised by continuous chickpea cultivation, intensive cropping and favourable soil environments, which are known to promote inoculum build-up and disease expression (Haware and Nene, 1980; Nikam et al., 2020) [5,14] . Moderate levels of wilt incidence were observed in Aurangabad (15.63%), Washim (15.11%), Nanded (14.48%), Latur (13.78%), Solapur (13.40%) and Ahmednagar (13.57%) districts, indicating intermediate disease severity. Comparable levels of incidence have been reported from Marathwada and adjoining regions by Patra et al., (2017) [17] and Sontakke et al., (2020) [21] . In contrast, comparatively lower wilt incidence (<10%) was recorded in Gadchiroli (6.81%), Gondia (7.78%), Chandrapur (7.81%), Beed (8.12%), Jalgaon (9.13%), Yavatmal (9.66%) and Bhandara (9.73%). Lower disease incidence in these districts may be attributed to less intensive chickpea cultivation, lighter soil texture and relatively cooler or forest-influenced agro-ecologies, as also suggested by Nathawat et al., (2020) [11] . The observed variation in wilt incidence among districts may also be associated with differences in soil physicochemical properties, cropping history, cultivar susceptibility and prevailing environmental conditions. Higher disease incidence in the central and Marathwada regions could be attributed to repeated cultivation of chickpea in the same fields, leading to the gradual accumulation of Fusarium oxysporum f. sp. ciceri inoculum in the soil. Furthermore, warm temperatures and moisture stress during the reproductive stage are known to favour disease development and wilt expression. Similar regional variations in chickpea wilt incidence and disease severity have been reported by Pande et al., (2012) [16] , Sharma and Ghosh (2016) [19] , Dubey et al., (2010) [3] , Jiménez-Díaz et al., (2015) [7] and Mahesh et al., (2019) [10] , who highlighted the combined influence of pathogen population density, environmental factors and host susceptibility on disease occurrence. [22] . 4. Available Nitrogen: Available nitrogen ranged from 121 to 260 kg ha⁻¹. Lower nitrogen levels in Parbhani and Sambhajinagar were associated with higher wilt incidence, although high nitrogen alone did not consistently suppress the disease, as observed in Akola (Haware et al., 1996) [23] . 5. Available Phosphorus: Available phosphorus ranged from 5.7 to 31.9 kg ha⁻¹. Districts showing phosphorus imbalance, such as Parbhani (deficiency) and Amaravati and Washim (excess), recorded moderate to high wilt incidence. Similar observations were reported by Patra et al., (2017) [17] . 6. Clay Content: Clay content ranged from 17.9 to 42.8 percent. Higher clay content was observed in Akola, Amaravati and Latur, which also recorded comparatively higher wilt incidence, indicating the favourable role of heavy clay soils in wilt development.

Conclusion

The present survey confirmed that chickpea wilt caused by Fusarium oxysporum f. sp. ciceri is widely distributed in the major chickpea-growing districts of Maharashtra, with disease incidence varying from 6.81 to 18.10 percent. The variation in wilt incidence among districts indicates the significant influence of local soil and environmental conditions on disease development. Higher wilt incidence was generally observed in districts with alkaline soils and greater clay content, while electrical conductivity showed little influence on disease occurrence. Overall, the study highlights the importance of soil characteristics, cropping practices, and environmental factors in the epidemiology of chickpea wilt. The findings provide useful baseline information for identifying disease-prone areas and formulating effective integrated management strategies for sustainable chickpea production.

References

1. Ahmad F, Gaur PM, Croser JS. Chickpea (Cicer arietinum L.). In: Genetic Resources, Chromosome Engineering and Crop Improvement. CRC Press; 2010.
2. Cho S, Muehlbauer FJ. Genetic effect of chickpea wilt caused by Fusarium oxysporum f. sp. ciceri. Plant Dis. 2004;88:817-824.
3. Dubey SC, Singh SR, Singh B. Morphological and pathogenic variability of Fusarium oxysporum f. sp. ciceri. Indian Phytopathol. 2010;63:273-277.
4. Gupta O, Kotasthane SR, Khare MN. Diseases of chickpea and their management. Technical Bulletin. JNKVV, Jabalpur; 1997.
5. Haware MP, Nene YL. Influence of wilt at different growth stages on yield loss in chickpea. Bull Trop Legumes. 1980;19:38-44.
6. Jalali BL, Chand H. Chickpea wilt. In: Plant Diseases of International Importance. Vol. 1. Prentice Hall, New Jersey; 1992. p. 429-444.
7. Jiménez-Díaz RM, Castillo P, Jiménez-Gasco MM, Landa BB, Navas-Cortés JA. Fusarium wilt of chickpeas: Biology, ecology and management. Crop Prot. 2015;73:16-27.
8. Jiménez-Fernández D, Jiménez-Díaz RM, TraperoCasas A. Persistence of Fusarium oxysporum f. sp. ciceri in soil. Plant Pathol. 2011;60:100-108.
9. Jukanti AK, Gaur PM, Gowda CLL, Chibbar RN. Nutritional quality and health benefits of chickpea (Cicer arietinum L.): A review. Br J Nutr. 2012;108(S1).
10. Mahesh M, Saifulla M, Prasad PS, Kulkarni S. Survey and incidence of Fusarium wilt of chickpea in major chickpea-growing areas of Karnataka. J Pharmacogn Phytochem. 2019;8(4):1887-1890.
11. Nathawat BDS, Sharma OP, Yadav AL. Studies on the incidence of wilt disease in major chickpea growing areas. Int J Chem Stud. 2020;8(3):263-265. doi:10.22271/chemi.2020.v8.i3d.9238.
12. Nene YL, Haware MP, Reddy MV. Chickpea diseases: Resistance-screening techniques. ICRISAT Information Bulletin No. 10; 1984.
13. Nene YL, Sheila VK, Sharma SB. A World List of Chickpea and Pigeonpea Pathogens. 5th ed. ICRISAT, Patancheru, India; 1996.
14. Nikam PS, Jagtap GP, Sontakke PL. Survey, surveillance and cultural characteristics of chickpea wilt caused by Fusarium oxysporum f. sp. ciceri. Afr J Agric Res. 2011;6(7):1913-1917.
15. Pande S, Sharma M, Gaur PM. Host plant resistance to chickpea diseases. Plant Dis. 2007;91:1221-1227.
16. Pande S, Sharma M, Gaur PM, Mangala UN. Disease management through monitoring and surveillance of chickpea diseases. Int Chickpea Newsl. 2012;18:12-18.
17. Patra S, Biswas B. Morphological, cultural and pathogenic diversity in Fusarium oxysporum f. sp. ciceri isolates on PDA. Plenum Press, New York. 2017;2:52-57.
18. Reddy MV, Mishra JP. Chickpea production and protection technologies. Indian Institute of Pulses Research, Kanpur; 2010.
19. Sharma M, Ghosh R. Occurrence and distribution of major chickpea diseases under diverse agro-ecological conditions. Legume Perspect. 2016;12:24-27.
20. Singh AK, Bharati RC, Chandra N. Disease management in chickpea. Indian J Pulses Res. 2007;20:45-52.
21. Sontakke PL, Dhutraj DN, Ambadkar CV, Badgujar SL. Status of chickpea wilt caused by Fusarium oxysporum f. sp. ciceri in Marathwada region of Maharashtra State. Int J Curr Microbiol App Sci. 2020;9(7):2553-2560.
22. Alabouvette C, Olivain C, Migheli Q, Steinberg C. Microbiological control of soil-borne phytopathogenic fungi with special emphasis on wilt-inducing Fusarium oxysporum. New Phytologist. 2009 Nov;184(3):529544.
23. Haware MP, Nene YL, Natarajan M. The survival of Fusarium oxysporum f. sp. ciceri in the soil in the absence of chickpea. Phytopathologia mediterranea. 1996 Apr 1:9-12.