INTRODUCTION Pigeonpea (Cajanus cajan (L.) Millsp is a valuable grain legume crop grown in the tropical and subtropical regions of the world (Varshney et al., 2010). Mature seeds contain 18.8% protein, 53% starch, 2.3% fat, 6.6% crude fiber and 250.3 mg 100 g−1 minerals (Ayenan et al., 2017). Productivity of pigeonpea is severely affected by several biotic and abiotic stresses. Of these biotic stresses of pigeonpea could result in complete yield loss. The pigeonpea sterility mosaic virus (PPSMV) causes sterility mosaic disease (SMD) often known as "green plague of pigeonpea". The symptoms include stunted growth, reduction in leaf size, mosaic mottling, chlorotic ring spots and cessation of reproductive structures in Fig. 3 and Fig. 5. PPSMV is one of the key biotic factors that causes high yield losses, poses a big challenge for pigeonpea production in the Indian subcontinent. According to reports, SMD causes an annual economic loss of $300 million in India alone (Patil and Kumar 2015). Variability in the sterility mosaic pathogen revealed the occurrence of five different isolates in India. Among them, three distinct SMD isolates have been characterized, viz., Patancheru, Bangalore and Coimbatore. Bangalore strains are the most severe, whereas, the Patancheru and Coimbatore variants are mild (Prabhavathi and Ramappa 2018). Pigeonpea is grown with minimal input; although chemical management of disease is effective, it is neither economical nor eco-friendly. Growing resistant varieties is one of the viable options of management to minimize economic losses. For better understanding of SMD, data on mite survival, host, host range and pathogen, as well as seasonal fluctuations in the mite population could be employed (Kaushik et al., 2013). The objective of this study was to find a genotype that confers wide and sustainable resistance to SMD. MATERIALS AND METHODS Screening of pigeonpea genotypes for SMD resistance was carried out in Department of Pulses, Tamil Nadu Agricultural University during rabi 2021-22. The materials used for the investigation includes seventy-four pigeonpea germplasms along with susceptible national check (ICP 8863) and resistant check (CO(Rg)7) obtained from Ramiah gene bank. The genotypes were sown in pots under glass house conditions given in Fig. 2a. Inoculum for Eriophyid mite was collected from susceptible check entry ICP 8863 (Maruthi) maintained at Department of Plant pathology, Tamilnadu Agricultural University, Coimbatore. The disease was transmitted through leaf stapling approach (Nene et al., 1976) shown in Fig. 2b. SMD infected leaf samples were gathered and examined under stereo zoom microscope for presence of Eriophyid mites (Aceria cajani), which transmits the SMD virus in Fig. 1. Collected leaf samples were stapled to the primary leaves of genotypes under screening. Mites from the diseased leaves moves towards healthy leaflets when the stapled leaf got dried. Plants were monitored for SMD incidence at 15 days interval from day after the first inoculation up to 90 days by counting the healthy plants (no mosaic symptoms) and diseased plants (with mosaic symptoms). Based on the disease development, the PDI was calculated using the formula Number of infected plants AICRP scale was assessed to evaluate the genotypes against SMD and classified as resistant, moderately resistant and susceptible based on disease reactivity listed in Table 1. RESULTS AND DISCUSSION Among the seventy-four genotypes screened for SMD along with national susceptible check ICP 8863 (Maruthi) and resistant (CO(Rg) 7) check with percent disease incidence given in Table 2. All the genotypes showed mild to severe mosaic ranging from 30 to 100 percent except CRG 16-07 and BWR 153. The genotypes viz., ICP 7919, IC 339057, IC 74016, IPAE 15-05, AL 2250, CRG 16-01, PusaArhar 21-14, PusaArhar 21-27, BWR 253, ICP 9808 and ICP 7234 were classified as moderately resistant with PDI ranging from 10.10 to 30 percent. Only two genotypes showed resistance reaction with 0-10 percent PDI listed in Table 3. Rest seventy-two genotypes showed mild to severe mosaic symptoms and were classified as susceptible ones. Relative and Absolute frequency were observed for seventy-four genotypes grouped into three reaction types listed in Table 3. Nearly 2.63 percent genotypes showed resistant reaction, 14.86 percent genotypes were found to be moderately resistant and 82.43 percent genotypes were classified under susceptible entries graphically represented in Fig. 4. Sharma et al. (2015) reported that eleven entries viz., ICP 3576, ICP 7869, ICP 9045, ICP 11015, ICP 11059, ICP 11230, ICP 11281, ICP 11910, ICP 14819, ICP 14976, and ICP 15049 were resistant to sterility mosaic disease. Joshi et al. (2017) discovered that out of total 188 RILs screened, 90 RILs showed resistant reaction to SMD infection, 98 RILs were susceptible and 33 RILs categorized as resistant lines which consistently showed 0 percent PDI. Bhaskar (2016) found that out of 60 entries screened for SMD resistance, eight entries viz., ICPL-87119, ICPL-2376, BDN-2, PT-4-307, CORG-9701, BSMR-736, GRG-811 and BSMR-853 showed resistant to sterility mosaic disease. Prabhavathi and Ramappa (2018) reported that all twenty-two IVT medium duration entries were susceptible to SMD, except Bahar, however only one IVT early duration entry, RKPV405-10, showed resistant reaction, while the others showed susceptible reaction. According to Tharageshwari et al. (2019), out of the ninety-four genotypes studied, only four genotypes, DPP 2-89, DPP 3-182, IC 22557, and ICP 3666 showed highly resistant reaction to SMD infection, whereas fifty-four genotypes showed highly sensitive reaction. Genotypes viz., CRG 16-07, BWR 153, ICP 7919, IC 339057, IC74016, IPAE 15-05, AL 2250, CRG 16-01, PusaArhar 21-14, PusaArhar 21-27, BWR 253, ICP 9808 and ICP 7234 were found to be SMD resistant ones and can be utilized as donors for resistant breeding program to reduce yield loss as compared to susceptible types.