Screening of chickpea varieties for resistance against the pulse beetle, Callosobruchus maculatus F. (Coleoptera: Bruchidae)

Introduction

Chickpea (Cicer arietinum L.), originating from Southeastern Turkey, holds a pivotal position among global leguminous crops (Ladizinsky, 1975; Toker, 2009) [9,22] . It dominates as the foremost rabi season food legume worldwide, cultivated across 15 m ha and yielding 15.9 mmt (Anonymous, 2023) [2] . Known for its nutritional richness, chickpea provides essential energy, protein, minerals, vitamins, fiber, and beneficial phytochemicals. Its nutrient-dense profile, often likened to "poor man's meat," makes it a popular choice for both human consumption and animal feed (Jukanti et al., 2012; Kaur and Prasad, 2021) [7,8] . The cultivation of chickpea spans approximately 57 countries, showcasing its adaptability to diverse environmental conditions (Mallikarjuna et al., 2000) [10] . India, as the largest producer, contributes significantly with 65% of the global production (9.07 mt) (Merga and Haji, 2019) [11] . Despite advances in breeding for increased yields and resistance to diseases, chickpea suffers notable losses post-harvest, estimated at 8.41%, with insect pests alone accounting for 1.18% in storage. Among these pests, Callosobruchus spp. (Chrysomelidae: Bruchinae: Coleoptera) are particularly destructive, causing extensive economic losses by rendering stored chickpeas unfit for consumption or seeding within 4-6 months. Their rapid multiplication in favorable conditions of high humidity and optimal temperature exacerbates these losses (Appleby and Credland, 2004) [3] . It is known to spend its entire immature life in individual legume seeds, feeds internally and hence responsible for huge weight loss decrease in germination potential thereby diminishing the market as well as the nutritional value of the commodity. The grub feeds and develops exclusively on the seed, while adults do not require food or water and spend their limited life span in mating and oviposition on seeds. Female beetle attaches its eggs individually on the testa of the seeds, hatched grubs borrow into the seed, feed on endosperm and embryo, undergoes a series of molts and pupates just underneath the seed coat. Although, the seed is still intact, around 1-2 mm hole is apparent at the location where the beetle is pupating. The adult that results from pupation chews through the seed coat and emerges from the seed, thus responsible for the formation of characteristic bored holes on the seed coat. The infestation of C. maculatus may commence from field or threshing floors, where matured seeds of chickpea may get infested. It causes (5-10%) damage in temperate regions and (20-30%) damage in tropical regions. Pest control in stored grains, including legumes, heavily relies on synthetic pesticides such as deltamethrin and malathion, alongside botanicals and physical methods like sun drying, to protect crops (Shaheen and Khaliq, 2005; Sharma et al., 2007) [17, 19] . However, concerns over pesticide resistance, residues, and environmental impacts on treated seeds often make them unsuitable. In response, there has been a growing emphasis on reducing chemical reliance and minimizing seed loss to bruchid attacks through enhanced host plant resistance in leguminous crops (Brewer and Horber, 1984; Shaheen et al., 2006) [4,18] . Cultivating tolerant or resistant chickpea cultivars offers a sustainable and cost-effective alternative that complements cultural and biological pest control methods without requiring additional farmer knowledge or costs. Studies assessing resistance in leguminous crops against bruchid species (Sarwar, 2012; Raghuwanshi et al., 2016) [, 16, 14] are crucial, with our study focusing on evaluating ten chickpea varieties for resistance against C. maculatus. By advocating for host plant resistance over synthetic pesticides, our research aims to promote the integration of resistant chickpea cultivars into comprehensive pest management strategies.

Materials and Methods

This experiment was conducted during September 2020 -July 2021 at Department of entomology Junagadh Agricultural University, Junagadh, Gujarat for six months.

Chickpea varieties

Ten desi chickpea varieties (GG 1, GG 2, GJG 3, GG 4, GG 5, GJG 6, JG 16, Dahod yellow, KAK 2, and AKG 1303) (Table 1) sourced from Pulse Research Station Junagadh, Agricultural University Gujarat, were assessed for their susceptibility to C. maculatus. Prior to the experiment, it was ensured that the chickpeas were free from any insect infestation.

Insect material and maintenance

The C. maculatus used in this study obtained from a laboratory colony maintained at the Department of Entomology, J.A.U. Junagadh. They were reared on chickpea seeds under controlled conditions of 30±2 ºC and 65±5% relative humidity in darkness. Chickpea seeds were cleaned and treated at 50 ºC for four hours to eliminate any potential infestations before being used for rearing (Patil, 2007) [13] . Eggs laid on these seeds were monitored daily in fresh jars until adult emergence, ensuring a consistent supply of beetles for the experimental investigations.

Resistance tests

The evaluation of chickpea varieties for their resistance or susceptibility to C. maculatus was conducted under a Completely Randomized Design (CRD). A no-choice method was employed, where each chickpea variety (GG 1, GG 2, GJG 3, GG 4, GG 5, GJG 6, JG 16, Dahod yellow, KAK 2, and AKG 1303) was individually screened against C. maculatus. In this method, 50g of seeds from each variety were placed in separate glass jars (7×8 cm 2 ), with each jar serving as one replication for the variety. The experiment included three replications for each of the ten chickpea varieties.

For each replication, ten pairs of one day old adults of C. maculatus were introduced into the jars and allowed access to the seeds for oviposition. The jars were covered with doublelayered muslin cloth and secured with rubber bands to prevent insect entry and escape while ensuring adequate air circulation.

After one week of exposure for oviposition, the adult insects were removed, and the jars were kept under controlled conditions of 30±2 ºC and 65±5% relative humidity. Emerging adult C. maculatus beetles from each jar were counted after 3 and 6 months of storage. Both live and dead adults were recorded, and seed weight loss was calculated as a % to assess the extent of damage caused by the beetles. This methodology aimed to evaluate the relative resistance or susceptibility of the chickpea varieties to C. maculatus infestation under controlled storage conditions.

Data collection and analysis

In the evaluation of chickpea varieties for resistance or susceptibility to C. maculatus using the no-choice test, several parameters were assessed: population growth (adult emergence), seed weight loss, and germination loss caused by the bruchid. Population growth was determined by counting the number of adult beetles that emerged from each variety after 6 months of storage. Seed weight loss was quantified by randomly selecting 100 grains from each replication of the variety, separating undamaged grains from those damaged by the bruchid larvae, and weighing them using an electronic balance. The % weight loss was calculated based on the formula: Furthermore, germination loss was assessed by comparing initial germination rates with those after 6 months of storage for each replication of every variety. Chickpea varieties were categorized into four groups of susceptibility to C. maculatus: highly resistant, resistant, susceptible, and highly susceptible. This categorization was based on the mean values of population growth, % weight loss, and % germination loss, using a scale modified from Ghelani (2016) [6] specifically for chickpea as given below. Statistical analysis employed Duncan's Multiple Range Test (DMRT) to identify significant differences among the chickpea varieties for each parameter, with a significance level set at *p<0.05. This rigorous evaluation aimed to provide insights into the relative resistance or susceptibility of the tested chickpea varieties to C. maculatus infestation under controlled experimental conditions, aiding in the selection of more resilient cultivars for effective pest management strategies in chickpea cultivation.

Results and Discussion

Ten chickpea varieties (GG 1, GG 2, GJG 3, GG 4, GG 5, GJG 6, JG 16, Dahod yellow, KAK 2, and AKG 1303) were subjected to laboratory testing to assess their resistance to C. maculatus using seed weight loss, germination loss, and population growth as key parameters. Based on their responses to C. maculatus infestation, these cultivars were categorized into four groups: highly resistant, resistant, susceptible, and highly susceptible.

Population growth (adult emergence)

The emergence of adult C. maculatus serves as a crucial indicator of the susceptibility or resistance of chickpea varieties to infestation. Over a period of three months, significant variation was observed in the number of adults that emerged among the ten tested chickpea varieties, reflecting their varying levels of resistance. Among the varieties tested, KAK 2 exhibited the highest susceptibility, with 17.68 adults emerging, indicating a lack of effective resistance mechanisms against C. maculatus. Similarly, AKG 1303 showed high susceptibility with 17.12 adult emergences. These findings suggest that both KAK 2 and AKG 1303 are likely to experience considerable post-harvest losses due to their inability to control pest development effectively. Varieties GG 1 and GG 2 showed intermediate susceptibility, with fewer adults developed compared to KAK 2 and AKG 1303, and were statistically similar to each other in their resistance levels. GG 5 and GG 4 demonstrated the highest resistance, with the least number of adults emerging, and were also statistically equivalent to each other in terms of their resistance. Following a 6-month storage period, KAK 2 and AKG 1303 remained the most susceptible varieties, with 21.12 and 20.35 adult emergences, respectively. Both varieties continued to exhibit statistically similar levels of susceptibility. Conversely, GG 5 maintained the lowest adult emergence, followed closely by GG 4, with statistically comparable levels of resistance.

Seed weight loss of chickpea varieties

Weight loss in chickpea seeds due to C. maculatus infestation after both three and six months of storage provides critical insights into the resistance or susceptibility of each variety.

After three months of storage, KAK 2 and AKG 1303 showed the highest weight losses at 36.83% and 34.26%, respectively, indicating their high susceptibility to pest infestation. GG 1 and GG 2 followed with weight losses of 31.89% and 32.05%, respectively, demonstrating moderate susceptibility. In contrast, GG 4 and GG 5 exhibited the least weight loss at 15.19% and 13.54%, respectively, with GG 5 showing the highest resistance.

After six months of storage, GG 4 and GG 5 maintained their resistance, with weight losses of 23.42% and 19.04%, respectively. These varieties continued to exhibit significantly lower weight losses compared to others, indicating their strong and durable resistance against C. maculatus.

Germination loss

Assessing germination loss due to Callosobruchus maculatus infestation after six months of storage provides critical insights into the resilience of chickpea varieties. Among the tested varieties, KAK 2 and AKG 1303 exhibited the lowest germination %, indicating their high susceptibility to pest damage. GG 4 and GG 5, on the other hand, demonstrated the least germination loss. GG 4 showed a decline from 77.39% to 54.14%, indicating a loss of 23.25%, while GG 5 decreased from 79.5% to 55.97%, with a loss of 23.53% (Table 2). These results underscore the strong resistance of GG 4 and GG 5 to C. maculatus, maintaining higher germination rates compared to other varieties. GG 5 particularly stood out with the least germination loss, highlighting its superior resistance and suitability as a resilient variety against C. maculatus infestation. GG 4 also showed notable resistance, making it a viable option for cultivation in regions prone to such pests.

The study assessed ten desi chickpea varieties (GG 1, GG 2, GJG 3, GG 4, GG 5, GJG 6, JG 16, Dahod yellow, KAK 2, and AKG 1303) against C. maculatus using a no-choice test, focusing on population growth (adult emergence), seed weight loss, and germination loss. The study demonstrated varying susceptibilities among the tested chickpea varieties to C. maculatus infestation. KAK 2 emerged as the most susceptible variety based on population growth (adult emergence), seed weight loss, and reduction in germination % after three and six months of storage. Following KAK 2, AKG 1303 also showed high susceptibility. Notably, KAK 2, characterized by its smooth, cream-colored seed coat and large seed size, exhibited particularly high susceptibility to C. maculatus (Table 1). These findings align with previous research by Eker (Eker et al., 2018) [5] who similarly found that pulse beetles preferentially laid eggs on chickpea cultivars with smooth seed coats in antibiosis tests.

Acknowledgement

AcknowledgementsThe authors thank all the teaching and non-teaching staff of Department of Entomology Junagadh Agricultural University, Junagadh, for their co-operation, support and for providing all the necessary facilities.

References

1. Anonymous. Database FAO. Available from: https://www.fao.org/faostat/en/#home. Accessed 2024 Jul 9.
2. Anonymous. FAOSTAT. The state of food security and nutrition in the world 2023. FAO. Available from: https://www.fao.org/3/cc3017en/online/cc30. Accessed 2024 Jul 9.
3. Appleby JH, Credland PF. Environmental conditions affect the response of West African Callosobruchus maculatus (Coleoptera: Bruchidae) populations to susceptible and resistant cowpeas. J Stored Prod Res. 2004;40(3):269-87.
4. Brewer IN, Horber E. Evaluating resistance to Callosobruchus chinensis Linn. in different seed legumes. 1984.
5. Eker T, Erler F, Adak A, Imrek B, Guven H, Tosun HS, et al. Screening of chickpea accessions for resistance against the pulse beetle, Callosobruchus chinensis L. (Coleoptera: Bruchidae). J Stored Prod Res. 2018;76:51-7.
6. Ghelani Y, Raghvani K, Ghelani M, Shah K, Polara N. Seed protecting efficacy of various insecticides against Rhyzopertha dominica (Fabricius) in stored pearl millet seeds. 2016.
7. 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):S11-26.
8. Kaur R, Prasad K. Technological, processing and nutritional aspects of chickpea (Cicer arietinum)-A review. Trends Food Sci Technol. 2021;109:448-63.
9. Ladizinsky G, Adler A. The origin of chickpea Cicer arietinum L. Euphytica. 1976;25:211-7.
10. Mallikarjuna BP, Patil BS, Meena S, Tripathi S, Bhat JS, Vijayakumar AG, et al. Breeding chickpea for climate resilience: An overview. In: Developing Climate Resilient Grain and Forage Legumes. 2022. p. 27-58.
11. Merga B, Haji J. Economic importance of chickpea: Production, value, and world trade. Cogent Food Agric. 2019;5(1):1615718.
12. Nisar MS, Haq IU, Ramzan H, Aljedani DM, Qasim M, Islam W, et al. Screening of different legumes for the developmental preference of Callosobruchus maculatus (Bruchidae: Coleoptera). Int J Trop Insect Sci. 2021;41:3129-36.
13. Patil DR. Population build-up, varietal screening and management of pulse beetle Callosobruchus chinensis (L.) through botanical materials in stored chickpea (Cicer arietinum L.). MSc Thesis (Unpublished). JAU, Junagadh; 2007.
14. Raghuwanshi PK, Sharma S, Bele M, Kumar D. Screening of certain gram genotypes against Callosobruchus chinensis L. (Coleoptera: Bruchidae). Legume Res Int J. 2016;39(4):651-3.
15. Saravanan L, Nivedhitha S, Pranusha P, Sivaraj N, Pandravada SR, Padmasri A, et al. Evaluation of cowpea [Vigna unguiculata (L) Walp.] germplasm against pulse beetle, Callosobruchus chinensis (L.), and correlation with morphological seed characters. Legume Res Int J. 2023;46(2):238-42.
16. Sarwar M. Assessment of resistance to the attack of bean beetle Callosobruchus maculatus (Fabricius) in chickpea genotypes on the basis of various parameters during storage. Songklanakarin J Sci Technol. 2012;34(3).
17. Shaheen FA, Khaliq A. Management of pulse beetle, Callosobruchus chinensis L. (Coleoptera: Bruchidae) in stored chickpea using ashes, red soil powder, and turpentine oil. Pak Entomol. 2005;27(2):19-24.
18. Shaheen FA, Khaliq A, Aslam M. Resistance of chickpea (Cicer arietinum L.) cultivars against pulse beetle. Pak J Bot. 2006;38(4):1237.
19. Sharma HC, Gowda CLL, Stevenson PC, Ridsdill-Smith TJ, Clement SL, Rao GR, et al. Host plant resistance and insect pest management in chickpea. In: Chickpea Breeding and Management. Wallingford, UK: CABI; 2007. p. 520-37.
20. Siyunda A, Mwila N, Mwala M, Kamfwa K. Laboratory screening of cowpea (Vigna unguiculata) genotypes against pulse beetle, Callosobruchus maculatus (F.). Medicon Agric Environ Sci. 2022;2(3):4-12.
21. Swamy SG, Raja DS, Wesley BJ. Susceptibility of stored chickpeas to bruchid infestation as influenced by physicochemical traits of the grains. J Stored Prod Res. 2020;87:101583.
22. Toker C. A note on the evolution of kabuli chickpeas as shown by induced mutations in Cicer reticulatum. 2009.