Final SPH -JHS Coverpage 16-2 Jan 2021 single C O N T E N T S JOURNAL OF HORTICULTURAL SCIENCES Volume 16 Issue 2 June 2021 In this Issue i-ii Review Phytoremediation of indoor air pollutants: Harnessing the potential of 131-143 plants beyond aesthetics Shalini Jhanji and U.K.Dhatt Research Articles Response of fruit yield and quality to foliar application of micro-nutrients in 144-151 lemon [Citrus limon (L.) Burm.] cv. Assam lemon Sheikh K.H.A., Singh B., Haokip S.W., Shankar K., Debbarma R. Studies on high density planting and nutrient requirement of banana in 152-163 different states of India Debnath Sanjit Bauri F.K., Swain S., Patel A.N., Patel A.R., Shaikh N.B., Bhalerao V.P., Baruah K., Manju P.R., Suma A., Menon R., Gutam S. and P. Patil Mineral nutrient composition in leaf and root tissues of fifteen polyembryonic 164-176 mango genotypes grown under varying levels of salinity Nimbolkar P.K., Kurian R.M., Varalakshmi L.R., Upreti K.K., Laxman R.H. and D. Kalaivanan Optimization of GA3 concentration for improved bunch and berry quality in 177-184 grape cv. Crimson Seedless (Vitis vinifera L) Satisha J., Kumar Sampath P. and Upreti K.K. RGAP molecular marker for resistance against yellow mosaic disease in 185-192 ridge gourd [Luffa acutangula (L.) Roxb.] Kaur M., Varalakshmi B., Kumar M., Lakshmana Reddy D.C., Mahesha B. and Pitchaimuthu M. Genetic divergence study in bitter gourd (Momordica charantia L.) 193-198 Nithinkumar K.R., Kumar J.S.A., Varalakshmi B, Mushrif S.K., Ramachandra R.K. , Prashanth S.J. Combining ability studies to develop superior hybrids in bell pepper 199-205 (Capsicum annuum var. grossum L.) Varsha V., Smaranika Mishra, Lingaiah H.B., Venugopalan R., Rao K.V. Kattegoudar J. and Madhavi Reddy K. SSR marker development in Abelmoschus esculentus (L.) Moench 206-214 using transcriptome sequencing and genetic diversity studies Gayathri M., Pitchaimuthu M. and K.V. Ravishankar Generation mean analysis of important yield traits in Bitter gourd 215-221 (Momordica charantia) Swamini Bhoi, Varalakshmi B., Rao E.S., Pitchaimuthu M. and Hima Bindu K. Influence of phenophase based irrigation and fertigation schedule on vegetative 222-233 performance of chrysanthemum (Dendranthema grandiflora Tzelev.) var. Marigold Vijayakumar S., Sujatha A. Nair, Nair A.K., Laxman R.H. and Kalaivanan D. Performance evaluation of double type tuberose IIHR-4 (IC-0633777) for 234-240 flower yield, quality and biotic stress response Bharathi T.U., Meenakshi Srinivas, Umamaheswari R. and Sonavane, P. Anti-fungal activity of Trichoderma atroviride against Fusarium oxysporum f. sp. 241-250 Lycopersici causing wilt disease of tomato Yogalakshmi S., Thiruvudainambi S., Kalpana K., Thamizh Vendan R. and Oviya R. Seed transmission of bean common mosaic virus-blackeye cowpea mosaic strain 251-260 (BCMV-BlCM) threaten cowpea seed health in the Ashanti and Brong-Ahafo regions of Ghana Adams F.K., Kumar P.L., Kwoseh C., Ogunsanya P., Akromah R. and Tetteh R. Effect of container size and types on the root phenotypic characters of Capsicum 261-270 Raviteja M.S.V., Laxman R.H., Rashmi K., Kannan S., Namratha M.R. and Madhavi Reddy K. Physio-morphological and mechanical properties of chillies for 271-279 mechanical harvesting Yella Swami C., Senthil Kumaran G., Naik R.K., Reddy B.S. and Rathina Kumari A.C. Assessment of soil and water quality status of rose growing areas of 280-286 Rajasthan and Uttar Pradesh in India Varalakshmi LR., Tejaswini P., Rajendiran S. and K.K. Upreti Qualitative and organoleptic evaluation of immature cashew kernels under storage 287-291 Sharon Jacob and Sobhana A. Physical quality of coffee bean (Coffea arabica L.) as affected by harvesting and 292-300 drying methods Chala T., Lamessa K. and Jalata Z Vegetative vigour, yield and field tolerance to leaf rust in four F1 hybrids of 301-308 coffee (Coffea arabica L.) in India Divya K. Das, Shivanna M.B. and Prakash N.S. Limonene extraction from the zest of Citrus sinensis, Citrus limon, Vitis vinifera 309-314 and evaluation of its antimicrobial activity Wani A.K., Singh R., Mir T.G. and Akhtar N. Event Report 315-318 National Horticultural Fair 2021 - A Success Story Dhananjaya M.V., Upreti K.K. and Dinesh M.R. Subject index 319-321 Author index 322-323 251 J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 This is an open access article d istributed under the terms of Creative Commons Attribution-NonCommer cial-ShareAl ike 4.0 International License, which permits unrestricted non-commercial use, d istribution, and reproduction in any med ium, provide d the original author and source are credited. Original Research Paper Seed transmission of bean common mosaic virus - blackeye cowpea mosaic strain (BCMV-BlCM) threaten cowpea seed health in the Ashanti and Brong-Ahafo regions of Ghana Adams F.K.1*, Kumar P.L.2, Kwoseh C.3 Ogunsanya P.2, Akromah R.3 and Tetteh R.1 1CSIR-Plant Genetic Resources Research Institute, P. O. Box 7, Bunso, Eastern region-Ghana 2International Institute of Tropical Agriculture (IITA), Oyo Road, PMB 5320, Ibadan, Nigeria 3Department of Crop and Soil Sciences, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, P.M.B., University Post Office, Kumasi, Ghana *Corresponding Author Email : ffffulera@yahoo.com ABSTRACT Antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect the presence and seed transmissibility of bean common mosaic virus-blackeye cowpea mosaic (BCMV-BICM) in farm- retained cowpea seed lots obtained from 46 locations, including markets and farms in major cowpea growing areas in the Ashanti and Brong Ahafo regions of Ghana. In the grow- out tests, virus symptomatic plants were observed in seedlings of 19 of the 46 seed lots tested under insect-proof screen-house conditions. All the symptomatic plants tested positive to polyclonal antiserum raised against BCMV-BICM in ACP-ELISA. The seed transmission rates based on symptoms ranged from 0 to 37.8 %. RT-PCR with primer pair designed to amplify the potyvirus Cylindrical Inclusion (CI) region resulted in an expected 720 bp DNA segment in 19 seed lots as a further confirmation of virus in the seed lots. The remaining 27 lots were asymptomatic and tested negative to BCMV-BlCM in both ACP-ELISA and RT- PCR. The findings of this study revealed seed as the source of primary inoculum in the farmers’ fields and may aid in the implementation of control strategies such as discouraging farmers from retaining their own seeds for subsequent sowing and encouraging them to take appropriate measures in obtaining virus-free cowpea seeds from other sources. Key Words: Bean common mosaic virus-blackeye cowpea mosaic, Cowpea, vegetable legume, ELISA, Potyvirus, RT-PCR, virus detection virus-seed transmission INTRODUCTION Cowpea (Vigna unguiculata (L.) Walp) is the most widely cultivated tropical vegetable legume in sub- Saharan Africa (SSA). It is predominantly produced by smallholder farmers because of its tolerance to drought and ability to thrive in zero or low input farming. It provides affordable protein for humans and animals in SSA, Asia, and Latin America (Bashir and Hampton 1993; Tarawali et al., 2002; Boukar et al., 2013) and also serves as a cover crop in soil nitrogen fixation a nd the contr ol of er osion a nd weeds (Hutchinson and McGiffen, 2000). Cowpea has the potential to enhance food security and reduce poverty in West Africa, provided both socio-economic and biological constraints such as poor application of appropriate cultural technologies, infestation by weeds and insect pests, and infection by diseases are adequately tackled (Jackai and Adalla, 1997; Quin, 1997; Coulibaly and Lowenberg – DeBoer, 2002; Boukar et al., 2013). In Ghana, cowpea is second to groundnut in terms of area under cultivation and quantity produced and consumed annually (Egbadzor et al., 2013). An average of 143,000 MT is produced annually on about 156,000 ha making Ghana the fifth-highest producer of cowpea in Africa (ICRISAT, 2012). The Guinea savannah zone of Ghana, which includes the Northern and Upper West regions, is the major production area in the country (Al-Hassan and Diao, 2007). Other 252 Adams et al J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 production areas include the Sudan savannah zone (Upper Ea st r egion) a nd some districts in the transitional zones of Brong Ahafo and Ashanti regions (Haruna et al., 2018). Bean Common Mosaic Virus – Blackeye Cowpea Mosaic (BCMV-BICM) is an important seed-borne virus reported in almost all cowpea growing areas worldwide (CABI/EPPO, 2010; Hema et al., 2014). Cowpea fields can suffer substantial yield losses from seed-borne pathogens (Bankole and Adebanjo, 1996). Sowing infected seeds increase germination failure, seedling mortality, and diseased plants, leading to lower yields. Additionally, diseased crops may increase seed infection levels in young plants (Manyangarirwa et al., 2009). Seed transmission offers an effective means of introducing viruses into crop fields at an early stage, giving r a ndomized foci of pr ima r y infections throughout the season, which serves as the primary inoculum source for further virus spread by insect vectors (Booker et al., 2005). Viruses may persist in cotyledons and embryo axes of matured seeds for long periods (Sekar and Sulochana, 1988), enabling scope for long distances virus spread through contaminated seed lots. T he r ole of fa r mer-sa ved seeds in transmitting cowpea diseases was analyzed in northern Nigeria (Biemond et al., 2013), and seed to plant transmission of seed-borne pathogens in farmer-saved cowpea wa s investiga ted in Zimba bwe (Manyangarirwa et al., 2009). These studies have shown that farmer-saved cowpea seeds were heavily infected, with a ra nge of seed- a nd soil-borne pathogens. T he latter empha sizes the negative influence on germination and potential crop losses. Infections caused by seed-borne viruses reduce seed quality and the potential yield of crops. Booker et al. (2005) reported seed transmission rates from less than 1 to 100% depending on the virus and host. Yield reductions from expected 2500kg/ha to 50kg/ha were also reported in fields infected with BCMV-BICM in India (Puttaraju et al., 2000a). Further, cowpea varieties inoculated with BCMV-BICM at the primary leaf stage showed 92-100% infection at first trifoliate lea f (http://cr opgenebank. sgr p. cgia r. org/ Da te accessed: 16/07/2019). The virus is readily transmitted mechanically and in a non-persistent manner by the aphids Aphis craccivora, A. gossypii, and Myzus persicae (Orawu, 2007). A survey conducted on cowpea fields in the Forest and Transitional zones of Ghana revealed the presence of BCMV-BlCM among other six viruses, namely, cowpea aphid-borne mosaic virus (CABMV, genus Potyvirus), cowpea mottle virus (CPMoV, genus Carmovirus), southern bean mosaic virus (SBMV, genus Sobemovirus), cowpea mild mottle virus (CPMMV, genus Carlavirus), cowpea yellow mottle virus (CYMV, genus Comovirus) and cucumber mosaic virus (CMV, genus Cucumovirus) with BCMV-BICM being the most prevalent (Adams et al., 2020). According to the study, farmers in the Forest and Transitional zones of the Brong-Ahafo and Ashanti regions adopt production practices such as high cropping density as a result of random sowing methods, recycling of seeds from season to season, the closeness of fields to each other with different planting and pesticide application periods as well as preference for and cultivation of susceptible local cowpea cultivars which increases the incidence and severity of viruses on fields in those areas (Amaza et al., 2010; Adams et al, 2016). During the 2015 growing season, vir al disease symptoms, similar to those caused by the BCMV- BlCM, were observed on cowpea fields in the Ashanti and Brong Ahafo regions of Ghana. Seeds collected from farmers in these areas were mostly shriveled. This study was conducted to confirm the virus identity in the symptomatic plants observed in the farmers’ fields and virus seed transmission in the seeds lots harvested from the 46 farmers’ fields and seed markets in Ghana. MATERIALS AND METHODS Seed sample collection A total of forty-six (46) cowpea seed lots were collected from randomly selected farms and markets in the Ama ntin-Atebubu (17 lots), Ejur a - Sekyeredumasi (13 lots), and Nkoranza (16 lots) districts. Seed lots were obtained from 24 farm locations (15 in Amantin-Atebubu, and 9 in Ejura- Sekyeredumasi) and 22 market locations (16 in Nkoranza, 2 in Amantin-Atebubu, and 4 in Ejura- Sekyeredumasi) (Table 1). Seeds sourcing from farmers was done by selecting cowpea farms separated by at least 0.5 Km in each district. In each farm, seed lots were obtained by collecting and bulking seeds from 30 plants randomly selected in an ‘X’ transect, 253 Seed transmission of bean common mosaic virus-blackeye cowpea mosaic strain with 15 plants per diagonal axis. For market-sourced seeds, lots were obtained by randomly collecting seeds from different market women during the main market days in each district. Seed samples were kept in labeled sample bags with naphthalene balls. A GPS device was used to record coordinates and altitudes of the field and market locations. Grow-out test From each sampled seed lot, 100 seeds were sown in trays filled with two liters of steam-sterilized topsoil in an insect-proof screen house. Cowpea seedlings were visually examined for any symptoms. The total number of plants germinated and the number of symptomatic plants was counted in each try to estimate the percent symptomatic plants. At the three-week sta ge, a pica l lea ves of both symptoma tic a nd asymptomatic plants were sampled for BCMV-BlCM indexing by antigen-coated plate enzyme-linked immunosorbent assay (ACP-ELISA). Symptomatic and asymptomatic plants were tested separately. In the case of asymptomatic plants, ten apical leaves, one from each plant, were collected, and they were together as one composite sample for virus indexing. This was repeated for all the seed lots. ACP-ELISA for BCMV-BICM detection To test each plant, a sterile cork borer was used to obtain 5 mm diameter pieces of all leaves in each of the 46 groups of leaf samples. About 100 mg of leaf tissue from each sample was grounded in the carbonate coating buffer (0.015 M Na 2CO3 and 0.0349 M NAHCO3) with DIECA at 100 mg/ml buffer (1:10 w/v). One hundred microlitres of the extract were added to each well of a microtitre plate. Infected, healthy plant sap and buffer were used as controls. Plates were incubated in a humid chamber for 1 hour at 37oC and then washed with three changes of phosphate-buffered saline with Tween 20 (PBS-Tween 20), allowing three minutes for each wash. Plates were emptied and tapped dry on a layer of paper towel. Wells were blocked with 200 µl of 3% dried skimmed milk in PBS-Tween 20. Plates were incubated at 37oC for 30 minutes, and then tapped dry. Healthy cowpea leaf extract in P BS - T PO ( 1 :1 0 w/ v) wa s u s ed t o c r os s - a dsor ption of the BCMV- BICM a ntiser u m a t 1:5000 µl. The mixture was incubated at 37oC for 30 minutes. One hundred microlitres of the cross- adsorbed antisera was dispensed in each well and plates were incubated at 37oC for 1 hour. Plates were washed and tapped dry as described above. One hundred microlitres of goat anti-rabbit alkaline phosphatase (ALP) conjugate diluted in conjugate buffer (Ovalbumin, Polyvinyl Pyrrolidone and PBS- Tween 20) (1: 15,000) were dispensed into each well and incubated for 1 hour at 37oC. Plates were washed and tapped dry. One hundred microlitres of 0.5 mg ml-1 p-nitrophenyl phospha te substr a te in substr a te buffer (diethanolamine and distilled water) were added to each well and incubated in a dark room for 1 hour. Absorbance values were measured, and plates were kept in a refrigerator at 4oC overnight. Quantitative mea sur ements of the p-nitr ophenyl substr a te conversion resulting in yellow colour were made by determining the absorbance at 405 nm (A405) in an ELISA plate reader at 1 and 6 hours. The mean absor ba nce readings of nega tive controls were determined, and twice the values were used as the positive thresholds. Reverse-transcription polymerase chain reaction (RT-PCR) The RT-PCR protocol described by Gillaspie et al. (2001) was used for the detection of BCMV-BlCM in the 46 seed lots to confirm the ACP-ELISA result. Total nucleic acid was extracted using the Cetyl Trimethyl Ammonium Bromide (CTAB) method described by Dellaporta et al. (1983). Cylindrical inclusions forward (CI-F; 5’- CGI VIG TIG GIW SIG GIA ART CIA C-3’) and reverse (CI-R; 5’-ACI CCR TTY TCD ATD ATR TTI GTI GC-3’) primers designed by Ha et al. (2008) were used for RT-PCR amplification and the RT-PCR products were resolved on a 1.5% agarose gel along with 100 bp DNA ladder as a size marker (Cat Nos N0467S, Quick-load, Biolabs Inc., Ipswich, MA, USA). The gel was viewed under a UV trans-illuminator (BioRad Gel Doc XR, California, USA), and the virus-specific band in the samples were identified based on the presence of an expected amplicon size of 720bp. RESULTS Among the 46 seed lots of cowpea subjected to a grow-out test in the screen-house, 19, made up of six lots obtained from Atebubu-Amantin, five from Ejura- Sekyeredumasi, and eight from Nkoranza, showed mottling and mosaic (Fig. 1) on leaves. J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 254 All the symptomatic plants of 19 seed lots also gave positive reactions to BCMV-BlCM in ACP-ELISA (Table 1). BCMV-BlCM transmission based on symptoms among the lots ranged from 0 to 37.8 % (Table 2). Some of the infected seed lots recorded low germination rates. For instance, of the 100 seeds of each seed lot planted, 51 of “Nkoranza-14” and 30 of “Amantin-15,” which were positive to BCMV- BICM, germinated. All asymptomatic plants tested negative to BCMV-BlCM in ACP-ELISA (Table 1). All the 19 seed lots that had symptomatic plants and tested positive to BCMV-BlCM have also tested positive to the virus in RT-PCR (amplified a 720 bp amplicon) (Fig. 2). Amplification was not detected in the remaining 27 asymptomatic seed lots (Fig. 4), confirming the results obtained using BCMV-BlCM antiserum in ACP-ELISA. DISCUSSION Grow-out tests, ACP-ELISA and RT-PCR have confirmed BCMV-BlCM seed transmission in the 19 of 46 seed lots assessed in this study. Aliyu et al. (20 12) pr evious ly detected BCMV-BI CM among other seed-borne viruses infecting cowpea in Nigeria, using ACP-ELISA. Like the results obtained in this study, several authors (Hampton et al., 1997; Shanker et al., 2009; Ittah and Binang, 2 0 1 2 ) ha ve a t va r iou s t imes p r oved s eed transmission of the virus. Shanker et al. (2009) reported BCMV-BlCM as a serious pathogen on cowpea worldwide, to which field plants succumb to infections from virulent strains. Booker et al. (2005) also reported the detrimental effect of the virus on cowpea production, causing stunting and plant deformation in the early growth stage and not allowing the plants to reach their full potential. Mottling and interveinal chlorosis observed on the primary leaves of the plants in the grow-out test were consistent with symptoms reported to be associated with infections caused by BCMV-BlCM (Aliyu et al., 2012). The BCMV-BlCM incidence in farmers’ fields and the corresponding seed transmission rates were given in Table 3. Some seed lots obtained from markets recorded seed transmission rates as high as 36.3% (Nkoranza-6) in the grow-out test. Some seed lots collected from farmers’ fields with high BCM V-BlCM incidences r ec or ded zer o seed- transmission (Amantin-2, -7, -13, -14 and Ejura- 3) while a few other lots recorded very low seed transmission values (Amantin-1, -11, Ejura-8 and -13). Amantin-6, Ejura-9, Amantin-5, and Ejura-4 recorded 100, 90, 87 and 83% field incidences, respectively, with corresponding seed transmission rates of 21.3, 37.8, 16.7 and 16.3%, respectively (Table 3). Low germination rates recorded in some infected seed lots may be attributed to infection by the BCMV-BICM. Ittah et al. (2010) reported in a previous study that seed-borne viruses such as BCMV-BICM, CABMV, CMeV, and SBMV may cause some infected cowpea lines to lose their Fig. 1. Mottle mosaic symptoms of seed-borne BCMV- BlCM on grow-out cowpea plants in a screen house Fig. 2. Agarose gel electrophoresis showing amplification of RT-PCR products Key; M = DNA marker, H = Healthy control, B = Buffer, D = Positive control Nkoranza samples: 1-16; Amantin samples: 17-33; Ejura samples: 34-46 Adams et al J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 255 Samples BCMV-BlCM Samples BCMV-BlCM Samples BCMV-BlCM Nkoranza 1 3.175* Amantin 1 2.658* Ejura 1 0.287 Nkoranza 2 0.253 Amantin 2 0.349 Ejura 2 2.658* Nkoranza 3 0.225 Amantin 3 0.367 Ejura 3 0.204 Nkoranza 4 0.222 Amantin 4 0.288 Ejura 4 3.370* Nkoranza 5 3.438* Amantin 5 3.383* Ejura 5 0.345 Nkoranza 6 3.446* Amantin 6 2.851* Ejura 6 0.282 Nkoranza 7 3.645* Amantin 7 0.247 Ejura 7 0.281 Nkoranza 8 3.445* Amantin 8 0.416 Ejura 8 3.457* Nkoranza 9 0.139 Amantin 9 0.373 Ejura 9 3.285* Nkoranza 10 0.249 Amantin 10 3.396* Ejura 10 0.224 Nkoranza 11 0.193 Amantin 11 2.962* Ejura 11 0.282 Nkoranza 12 3.174* Amantin 12 0.568 Ejura 12 0.283 Nkoranza 13 3.381* Amantin 13 0.316 Ejura 13 3.322* Nkoranza 14 3.275* Amantin 14 0.471 Nkoranza 15 0.517 Amantin 15 3.140* Nkoranza 16 0.285 Amantin 16 0.410   Amantin 17 0.419 Positive control OUT OUT OUT Negative control 0.268 0.36 0.36 Buffer 0.21 0.28 0.28 *Absorbance value (A405 nm) is >2x of negative control regarded as the virus positive. “OUT” indicates an out-of-range value (A405 >4) Table 1. ACP-ELISA result for BCMV-BlCM seed transmission Table 2. Seed transmission rates of BCMV-BlCM among accessions Seed transmission rate (%) Number of seed lots 0 27 0.1 - 5.0 6 5.1 - 10 0 10.1 - 20 4 20.1 - 30 4 30.1 - 37.8 5 ability to germinate. Fawole et al. (2006) also analyzed the effect of seed-borne fungi infection of cowpea seed on germination rate and found reduced germination rate because of infection by the fungi. Further, Manyangarirwa et al. (2009) reported that f a r mer - pr odu ced c owp ea s eeds wer e hea vily infected with a r a nge of seed- a nd soil-bor ne pathogens in Zimbabwe, emphasizing the negative influence on germination. However, in contrast to the above findings, Biemond et al. (2013) found that natural infection of cowpea seeds with some seed-borne pathogens increased germination. Alt hou gh BC MV- BI C M ha s b een p r eviou sly detected in cowpea seeds in Ghana (Zettler and Evans, 1972), according to the literature available, most previous detections were limited to grow-out test , host r a nge, a nd r ea ct ivity t o polyclona l a ntibodies. Ojueder ie et al. (2009) suggested stringent screening methods such as RT PCR to be used in screening for the presence of seed-borne viruses in a ddition to ELISA, which employs reactivity to polyclonal antibodies since samples which appear nega tive with the latter could be positive when tested with RT PCR. The study confor ms with the a bove r ec ommenda tion a s BCMV-BlCM was assessed with ACP-ELISA, and the results were confirmed with RT-PCR. BCMV-BlCM was identified to be seed-borne in cowpea collected fr om fa r ms a nd ma r kets in Seed transmission of bean common mosaic virus-blackeye cowpea mosaic strain J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 256 Cowpea Seed Total Total Total % Field Transmission Seed lots source sown germinated symptomatic incidence rate (%) Nkoranza 1  Market 100 53 18 * 34 Nkoranza 2  Market 100 42 0 * 0 Nkoranza 3  Market 100 93 0 * 0 Nkoranza 4  Market 100 58 0 * 0 Nkoranza 5  Market 100 63 14 * 22.2 Nkoranza 6  Market 100 80 29 * 36.3 Nkoranza 7  Market 100 91 28 * 30.8 Nkoranza 8  Market 100 65 10 * 15.4 Nkoranza 9  Market 100 36 0 * 0 Nkoranza10  Market 100 71 0 * 0 Nkoranza11  Market 100 89 0 * 0 Nkoranza12  Market 100 87 18 * 20.7 Nkoranza13  Market 100 80 19 * 23.8 Nkoranza14  Market 100 51 16 * 31.4 Nkoranza15  Market 100 68 0 * 0 Nkoranza16  Market 100 50 0 * 0 Amantin 1  Farm 100 60 1 63 1.7 Amantin 2  Farm 100 68 0 50 0 Amantin 3  Farm 100 52 0 30 0 Amantin 4  Farm 100 42 0 33 0 Amantin 5  Farm 100 78 13 87 16.7 Amantin 6  Farm 100 94 20 100 21.3 Amantin 7  Farm 100 63 0 70 0 Amantin 8  Farm 100 69 0 38 0 Amantin 9  Farm 100 82 0 38 0 Amantin 10  Farm 100 96 12 87 12.5 Amantin 11  Farm 100 100 4 60 4 Amantin 12  Farm 100 73 0 45 0 Amantin 13  Farm 100 76 0 87 0 Amantin 14  Farm 100 65 0 57 0 Amantin 15  Market 100 30 1 * 3.3 Amantin 16  Farm 100 83 0 30 0 Amantin 17  Market 100 33 0 * 0 Ejura 1  Farm 100 42 0 43 0 Ejura 2  Market 100 86 2 * 2.3 Ejura 3  Farm 100 62 0 63 0 Ejura 4  Farm 100 80 13 83 16.3 Ejura 5  Farm 100 82 0 30 0 Ejura 6  Market 100 72 0 * 0 Ejura 7  Farm 100 71 0 17 0 Ejura 8  Farm 100 92 1 50 1.1 Ejura 9  Farm 100 90 34 90 37.8 Ejura 10  Market 100 66 0 * 0 Ejura 11  Market 100 57 0 * 0 Ejura 12  Farm 100 63 0 40 0 Ejura 13  Farm 100 80 1 53 1.3 *Denotes unknown (seed lots sourced from markets) Table 3. BCMV-BlCM incidence in farmers cowpea fields and respective seed transmission rates observed in grow-out test Adams et al J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 257 Nkoranza, Amantin, and Ejura. A study conducted by Biemond et al. (2013) showed that farmer- produced cowpea seeds were heavily infected with a r a nge of s eed- a nd s oil- b or ne p a t hogens . Transmission rates based on symptoms ranged from 0 to 37.8 %. Ladipo (1977) and Ng and Hughes (1998) estimated that the rate of seed-transmission of virus in cowpea may range from 0 to 90%, which aligns with the seed transmission rates observed in this study and a previous study by Zettler and Evans (1972) that showed the frequency of seed transmission of BCMV-BlCM at about 30.9% in cowpea. Seed transmission rates of BCMV-BlCM did not necessarily correspond with infection levels observed in fields from which the collections were made. Although some lots obtained from fields with high disease incidence recorded correspondingly high transmission rates in the grow-out test, others recorded either zero or very low rates. Low transmission rates of BCMV-BlCM in seed lot s ob t a in ed f r om f ields wit h h igh dis ea s e incidences c ould b e du e t o s ever a l r ea s ons , including infection after flowering to the presence of virus in seed coat but not in the embryos (Gupta et al., 1985). Shanker et al. (2009) showed that sowing cowpea seeds with the incidence of BCMV- BlCM a s low as less than 1% might result in significant virus spread with a major influence on grain yield. Puttaraju et al. (2004b) also reported a 65-100% BCMV-BlCM transmission resulting from sowing cowpea seeds with a bout 4-10% infection rate. Thus, even with the relatively low seed transmission rates observed in the current study, there is cause for concern. According to Shanker et al. (2009), a threshold level below 2% infection for cowpea seeds is recommended as suitable to avoid the risk of economic losses due to the spread of BCMV-BlCM in cowpea. Seed-borne vir uses can pr esent a cha llenge to ma na ging v ir a l dis ea s es in t he f ields a nd complicate the transfer of seeds by trade and other met hods of s eed ex c ha nge b et we en f a r mer s (Manyangarirwa et al., 2009; Ittah et al., 2010; Biemond et al., 2013). Recycling farmers’ seeds for subsequent planting, as in the present study areas, may result in high virus incidence and significant yield loss (Owolabi et al., 1988). In conclusion, this study demonstrated a high risk of seed-borne virus threat in the farmer-saved seed. It showed a need to improve awareness among farmers and extension agents about the risk of seed- borne virus infections and discourage farmers from reusing their seeds for long periods, particularly those harvested from infected fields. This study also calls for an increase in the supply of certified seed production that will serve as a sustainable solution to reduce the risk of BCMV-BlCM threat to cowpea production in Ghana. ACKNOWLEDGEMENTS Authors acknowledge the West African Agriculture Productivity Program (WAAPP-Ghana) who funded the research work in Ghana, and the International Institute for Tropical Agriculture (IITA), Ibadan, Nigeria, for supporting virus diagnostics research. Authors appreciate funding from CGIAR Research Program on Dryland Cereals and Legumes. Seed transmission of bean common mosaic virus-blackeye cowpea mosaic strain J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 REFERENCES Ada ms , F. K . , K u ma r, L . , K wos eh, C . a nd Akromah, R. 2020. Occurrence of cowpea viruses in the forest a nd sa va nna h a gr o- ecological zones of Ghana. African Crop Science Journal, 28(3):443-450. Adams, K. F. 2016. Survey of cowpea viral disease symptoms and detection of associated viruses in selected cowpea growing areas in Ghana. MPhil Thesis, KNUST, Ghana. Al-Hassan, R. M. and Diao, X. 2007. Regional dispa r ities in Gha na : policy options and p u blic inves tment imp lica t ions . G ha na St r a t egic S u p p or t P r ogr a mme . ht t p :/ / www.ifpri.org/ themes/gssp/gssp.htm. Aliyu, T. H., Balogun, O. S. and Kumar, L. 2012. S u r vey of t he s ymp t oms a n d vir u s es associated with cowpea in the agro ecological zones of Kwara State, Nigeria. Ethiopian J ou r na l o f E n vi ron me n ta l St ud i es an d Management, 4(5):2 258 Amaza, P.S., Udo, E.J., Abdoulaye, T., Kamara, A.Y. 2010. Analysis of technical efficiency among community-based seed producers in the savannas of Borno State, Nigeria. J. Food Agric. Environ., 8:1073-1079. Bankole, S.A. and Adebanjo, A. 1996. Biocontrol of b r own b lot c h of c owp ea c a u s ed b y Colletotrichum truncatum with Trichoderma viride. Crop Protection, 15:633-636. Bashir, M. and Hampton, R. O. 1993. Natural occurrence of five seed-borne cowpea viruses in Pakistan. Plant Disease, 77: 948-951 Biemond, P. C. , Ogunta de, O. , Kuma r, P. L . , Stomph, T.J., Termorshuizen, A. and Struik, P. 2013. Does the infor ma l seed system t hr ea t en c owp ea s eed h ea lt h? C ro p Protection, 43:166-174. Booker, H. M., Umaharan, P. and McDavid, C. R. 2005. Effect of Cowpea Severe Mosaic Virus on crop growth characteristics and yield of cowpea. Plant Disease, 89:515-520. Boukar, O., Bhattacharjee, R., Fatokun, C., Kumar, P. L. a nd Gueye, B. 2013. Cowpea , In: Genetic and Genomic Resources of Grain Legume Improvement. Elsevier, Sing, M. and Bisht, S. I. (eds.). p 137-156. CAB International/European and Mediterranean Plant Protection Organization 2010. Cowpea aphid-borne mosaic virus. Distribution maps of plant diseases, Wallingford, UK: CABI, Map 1075. Coulibaly, O. and Lowenberg-DeBoer, J. 2002. The economics of cowpea in West Africa, In: Challenges and Opportunities for Enhancing Sustainable Cowpea Production. Conference Proceedings, IITA, Ibadan, Nigeria. p 351- 366. Dellaporta, S. L., Wood, J. and Hicks, J. B. 1983. A plant DNA mini preparation version II. Plant Molecular Biology Reporter, 1:19-21. Egbadzor, F. K., Yeboah, M. Ofei, S. K., Ofori, K. a nd Da nqua h, E. Y. 2013. Fa r mer s key production constraints and traits desired in cowpea in Ghana. Journal of Agriculture and Ru ral De vel opm ent i n t he Tro pic s a nd Subtropics, 5(1):14-20. Fawole, O. B., Ahmed, O. and Balogun, O. S. 2006. Pathogenicity and cell wall-degrading enzyme activities of some funga l isolates from cowpea (Vigna unguiculata [L.] Walp). Biokemistri, 18:45-51 Gillaspie Jr. A. G., Pio-Ribeiro, G., Andrade, G. P. and Pappu, H. R. 2001. RT- PCR Detection of Cowpea Aphid-bor ne Mosa ic vir us in Peanut from Brazil. Phytopathology, 91:2002 Gupta, B. M., Singh, B. P., Verma, H. N. and Srivastara, K. M. 1985. Perspectives in plant vir ology, Vol 1 , P r int H ou s e ( I ndia ) Lucknow, p. 299-314. Ha, C., Coombs, S., Revill, P. A., Harding, R. M., Vu, M. and Dale, J. L. 2008. Design and application of two novel degenerate primer pairs for the detection and complete genomic characterization of Potyviruses. Archives of Virology, 153:25-36. Hampton, R. O., Thottappilly, G. and Rossel, H. W. 1997. Viral diseases of cowpea and their control by resistance conferring genes. In: Adva nc es in C owp ea R es ea r c h. I I TA/ JIRCAS. Singh, B. B., Mohan Raj, D. R., Dashiel, K. E. and Jackai, L. E. N. (eds.). p 159-175. Haruna, P., Asare, A. T., Asare-Bediako, E. and Kusi, F. 2018. Fa rmers a nd agricultura l extension officer s ’ per c eption of Str iga gesnerioides (Willd.) Vatke parasitism on cowpea in the Upper East Region of Ghana. Advances in Agriculture 7319204, p 11. https://doi.org/10.1155/2018/7319204 Hema, M., Sreenivasulu, P., Patil, B. L., Kumar, P. L. and Reddy, D. V. R. 2014. Tropical food legumes: virus diseases of economic Adams et al J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 259 importance and their control. Advances in Virus Research 90: 431-505. Hutchinson, C. M. and McGiffen, M. E. Jr. 2000. Cowpea cover crop mulch for weed control in desert pepper production. Horticultural Science, 35:196-198. International Crops Research Institute for the Semi- Ar id Tr opic s 201 2. C owpea fa r ming in Ghana. Bulletin of Tropical Legumes, http:/ /www.n2africa.org/sites/n2africa .org/fles/ images/BTL16-20122712 0.pdf. Ittah, M. A. and Binang, W. B. 2012. Screening cowpea (Vigna unguiculata (L.) Walp) lines for resistance to some viruses in Nigeria. Continental Journal of Agricultural Science, 6 (1):50-55 Ittah, M. A., Fa wole, I. , Shoyinka , S. A. and Hughes, J. D. A. 2010. Sources of resistance to seed tr ansmission of some seed-bor ne vir u s es of c owp ea . G l o b a l J o u r n a l o f Agricultural Sciences, 9:69-75. Jackai, L. E. N. a nd Adalla, C. B. 1997. Pest management practices in cowpea: a review. In: Advances in Cowpea Research. IITA/ JIRCAS. Singh, B. B., Mohan Raj, D. R., Dashiel, K. E. and Jackai, L. E. N. (eds.). p 240-258. Ladipo, J. L. 1977. Seed transmission of cowpea aphid-borne mosaic virus in some cowpea c u lt iv a r s . N i g e r i a n J o u r n a l o f Pl a n t Protection, 3:3-10 Manyangarirwa, W., Bwerazuva, T. and Mortensen, C. N. 2009. Seed-borne fungal and bacterial pathogens on farm-retained cowpea seeds fr om Zimb a bwe. Af ri ca n Crop S ci en ce Conference Proceedings, 9:595-599. Ng, N.Q. and Hughes, J.D.A., 1998. Theoretical a nd p r a c t ic a l c ons ider a t io ns in t he regeneration of cowpea germplasm at IITA. In Regeneration of Seed Crops and Their Wi l d R e l a t i v e s : Pro c e e d i n g s o f a Consultation Meeting, 4-7 December 1995, ICRISAT, Hyderabad, India, 26 (40):76. Ojuederie, O. B., Odu, B. O. and Ilori, C. O. 2009. Serological detection of seed borne viruses in cowpea regenerated germplasm using protein a sandwich enzyme linked immunosorbent assay. African Crop Science Journal, 17:125-132. Orawu, O. 2007. Occurrence of Cowpea aphid- b or ne mos a ic vir u s a nd p r o s p ec t s of impr oving r es ist a nc e in loca l c owp ea landraces in Uganda. PhD thesis, University of Makerere, Uganda Owolabi, A. T., Taiwo, M. A. and Mabadeje, S. A. 19 88 . E ff ect s of s ingle a nd mixed inoculations with blackeye cowpea mosaic virus on two Nigerian cowpea cultivars. Nigeria Journal of Basic and Applied Science, 2:25-33 Puttaraju, H. R., Prakash, H. S. and Shetty, H. S. 2000a. Field incidence, seed-transmission and susceptibility of cowpea varieties with r ef er ence to Bla ckeye Cowp ea Mos a ic Potyvirus. Seed Research, 28(2):196-202 Puttaraju, H. R., Prakash, H. S. and Shetty, H. S. 2 00 4b . Seed infection by Bla c keye cowpea mosaic potyvirus and yield loss in differ ent cowpea va r iet ies. Jo ur na l of Mycology and Plant Pathology, 34:41-46 Quin, F. M. 1997. Introduction. p ix-xv. In: Advances in Cowpea Research. Singh, B. B., Mohan Raj, D. R., Dashiel, K. E. and Jackai, L. E. N. (eds.). IITA/JIRCAS. Seka r, R. a nd Suloc ha na , C. B. 1988. Seed transmission of blackeye cowpea mosaic vir us in two cowpea va rieties. Current Science, 57(1):37-38 Shanker, U. C. A., Nayaka, S. C., Kumar, H. B., Shetty, H. S. and Pra kash, S. H. 2009. Detection and identification of the Blackeye cowpea mosaic str a in of Bea n common Seed transmission of bean common mosaic virus-blackeye cowpea mosaic strain J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 260 (Received on 24.11.2021, Revised on 09.12.2021 and Accepted on 11.01.2022) Adams et al J. Hortl. Sci. Vol. 16(2) : 251-260, 2021 mosaic virus in seeds of cowpea in Southern India. Phytoparasitica, 37:283-293 Tarawali, S. A., Singh, B. B., Gupta, S. C., Tabo, R., Harris, F., Nokoe, S., Fernandez-Rivero, S., Bationa, A., Manyong, V. M., Makinde, K. and Odion, E. C. 2002. Cowpea as a key factor for a new approach to integrated crop- lives t oc k s ys t ems r es ea r c h i n t he dr y savannas of West Africa. In: Challenges and Opportunities for Enha ncing Susta inable C owp ea P r odu c t ion. Wor l d C owp ea c onf er ence p r oc eedings (I I TA) Ib a da n, Nigeria. p 233-251. Zettler, F. W. and Evans, I. R. 1972. Blackeye cowpea mosaic virus in Florida. Host range a nd incidence in certified cowpea seeds. Fl o r i d a St a t e H o r t i c u l t u r a l S o c i e t y proceedings, 85:99-101. 00 Contents.pdf 14 Adams.pdf 19 Lamesssa.pdf 20 Divya.pdf 21 Wani.pdf 23 Index and Last Pages.pdf