Determination of scanned virus-free potato planting materials by positive selection and screening of tubers from seed stores in the western highlands of Cameroon (original) (raw)
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Potato (Solanum tuberosum L.) is an important cash-food crop, which is widely grown in three of the five agro-ecological zones of Cameroon. A study was carried out to determine the prevalence of PVA, PLRV, PVM, PVS, PVX and PVY in 1175 sprouted potato seed tubers of different diameters collected from four seed stores in the North West Region of Cameroon. The study also sorts to ascertain variations in virus incidence in small, medium and large size sprouted tubers prior to planting. The DAS-ELISA method was used to test for the presence of these viruses. Results showed significant differences in the prevalence of the six viruses with PVM being the most prevalent (92%), while PLRV was least prevalent (35%) in all the four seed stores sampled. Upper-Farm store registered the highest relative prevalence (82%), with PVM detected in all the tubers while samples from Rock-Farm store showed the least relative incidence (55%) with no PLRV detected. Viruses were significantly most prevalent in small size tubers (71%) and least in large size potato tubers (63%). Our results suggest that tuber size can serve as a guide to identify healthy (virus-free) tubers. Farmers could therefore use large size potato tubers for planting.
2021
Solanum tuberosum L. is considered by the Food and Agricultural Organization as one of the alternative food crops that can help to fight against hunger in the world. However, this crop species is subject to numerous attacks, among which viruses are responsible for causing considerable losses of crop quality and yield. The objective of this study was to detect Potato virus X (PVX), Potato virus Y (PVY) and Potato leaf roll virus (PLRV) and to determine the prevalence of these viruses in potato farms in the Western Highlands of Cameroon. For this purpose, 600 symptomatic and 200 asymptomatic leaf samples were collected from 20 potato fields distributed in low (O
Assessment of prevalence and distribution of potato viruses in Ethiopian seed systems
Viruses are among the significant biotic constraints burdening global potato production, particularly in developing countries where seed certification is not common and production, availability and accessibility to quality seed potato is a big hindrance. Virus infection in seed potato reduces yield, and the problem is exacerbated when an early-generation seed is affected. The prevalence of six key potato viruses, PVY, PVX, PLRV, PVA, PVS, and PVM, was assessed among decentralized seed multipliers such as individuals, farmer seed group cooperatives, private companies, and agricultural research center that produce early generation seed in six major potato growing districts in Ethiopia. A total of 262 leaf samples were randomly collected from potato plants and analyzed using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for potato viruses. Potato virus prevalence was calculated as the proportion of samples that tested positive for the viruses against the tota...
Deleted Journal, 2024
Virus infection in seed potato reduces yield, and the problem is exacerbated when an early-generation seed is affected. The prevalence of six key potato viruses, PVY, PVX, PLRV, PVA, PVS, and PVM, was assessed among decentralized seed multipliers such as individuals, farmer seed group cooperatives, private companies, and agricultural research centers that produce early generation seed in six major potato growing districts in Ethiopia. A total of 262 leaf samples were randomly collected from potato plants and analyzed using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for six major potato viruses. Potato virus prevalence was calculated as the proportion of samples that tested positive for the viruses against the total number of samples tested. The prevalence of infection with at least one of the six viruses was 98.2%. Among the samples analyzed, 17.2% had a single viral infection with one of the six viruses while the majority had multiple infections. The ELISA tests confirmed presence of latent virus infection in early generation seeds from the three EGS producers and in different seed classes. This result indicates that virus infection is widespread in the country, limiting potato production. To address this issue, it is critical to develop a robust system that prevents viral infection build-up and spread in the seed system through regular seed quality assurance and certification, particularly for early generation seed. Article Highlights • Most of the materials including seed potato nuclear stocks were infected with potato viruses beyond the acceptable levels more so in being found in breeder seed. • Viruses are likely to occur throughout the country's seed potato system and also becoming to the second most important potato diseases next to bacterial wilt for EGS production in Ethiopia. • Unless intervention is made on seed potato systems, viruses are now threatening the livelihoods of already vulnerable smallholder potato farmers in Ethiopia.
Distribution of potato viruses in Uganda
African Crop Science Journal
Viral diseases are among the major factors affecting potato (Solanum tuberosum L.) production in Uganda. Knowledge of the types of viruses and their distribution levels in the country is vital for targeting sound management strategies. The objective of this study was to assess the prevalence and distribution of potato viruses in different potato growing areas in Uganda. Virus diagnostic surveys were conducted across the main potato producing regions and virus detection was done using DAS-ELISA and RT-PCR techniques. The study showed that the most widely distributed and economically important potato viruses were: PVS (31-90.9%), PLRV (2.6-81.3%), PVY (7.1-54.5%) and PVX (8.3 -53.3%); while the least detected viruses were PVM (18.2%) and PVA (9%). The viruses were prevalent either singly or in mixtures. Up to 42.8% of the samples were infected with one virus, 20.9% with two viruses and 4.2% with three viruses; while no virus was detected in 31.3% of the samples. Of the double infectio...
Potato Research
Smallholder farmers in Uganda commonly use seed potato tubers from the informal sector, especially by seed recycling over several generations. Therefore, seed tubers are highly degenerated with viruses and other pathogens, resulting in poor yield and quality of the produce. Over one cycle of multiplication, degeneration management by positive seed selection was found to be efficient in reducing virus diseases compared with the farmers' method of selection. The objective of this study was to assess to what extent positive selection over several seasons can reduce six different virus incidences in seed lots of different starting quality in southwestern Uganda. Multi-seasonal trials were carried out in three locations, with five seed lots from four sources and three cultivars. Detection of viruses was based on DAS-ELISA and Luminex xMAP technology. Analysis was carried out with analysis of variance (ANOVA) on angulartransformed percentages of virus incidence. Results showed fluctuations in some viruses over seasons with lower Potato leafroll virus (PLRV) and Potato virus X (PVX) incidences in lots from positive selection compared with lots from farmers' selection. In contrast, some seed lots were initially highly infected with Potato virus S (PVS) and Potato virus M (PVM) and showed no reduction in virus incidence through positive selection. In general, little infection with Potato virus Y (PVY) and Potato virus A (PVA) was found. Based on these results, it is recommended that smallholder farmers are trained in positive selection to opt for less virus-infected plants and tubers, thus increasing potato production.
2014
Development of alternative serological techniques to ELISA for detection of potato viruses offers advantages for monitoring virus incidence and for seed potato certification systems. Several trials showed that multiplex tissue print immunoassay (TPIA) and dot blot immunoassay (DBIA) might represent fast, practical, and sensitive alternatives for the detection of: Potato leaf roll virus (PLRV), Potato virus S (PVS), Potato virus X (PVX) and Potato virus Y (PVY), from green and/or tuber tissues. In TPIA, the specific precipitation patterns in infected tissues of leaf petioles or stem cross sections, observed with each virus, allowed identification of the specific virus or mixed infections in a single multiplex assay. For detection of PVY in green tissues, DBIA was shown to be over 50 times more sensitive than ELISA. TPIA and ELISA from the tuber stem end or from eyes might be used for rapid detection of PVY and PVS in seed potato tubers without prior germination. PVS was evenly distributed in potato tuber tissue, while PVY was localized in the vascular tissue beneath the epidermis, with irregular distribution along the periphery of the potato tuber. For laboratories in developing countries lacking time and facilities for tests based on tuber germination, monitoring for PVS and PVY using TPIA in tuber tissue may be a suitable alternative to ELISA.
Phytopathologia Mediterranea, 2001
Potato fields in the two main production areas of Lebanon, the Bekaa and Akkar plains, were surveyed in two growing seasons for viruses and other pathogens of significance for a potato seed certification program. ELISA tests showed that Potato virus Y (PVY) was the predominant virus, followed by Potato virus A (PVA), Potato virus X (PVX), Potato virus M (PVM), Potato virus S (PVS) and Potato leaf roll virus (PLRV). Of 789 samples tested by ELISA during the two growing seasons, 372 samples were infected by one or more viruses. Single, double and multiple infections represented 75.3, 21.2 and 3.5% of all infected samples, respectively. Incidence of viruses was higher on crops from locally produced uncertified seed-potatoes than on crops from imported certified seed-potatoes. In nucleic acid spot hybridization assays, all 109 samples tested for potato spindle tuber viroid were negative. Other important pathogens of quarantine interest, including Clavibacter michiganensis, Ralstonia solanacearum and Synchytrium endobioticum, were not detected.
Effectiveness of Positive Selection in Managing Seed-Borne Potato Viruses
2018
Potato productivity in Kenya has remained below the potential due to the use of infected seed tubers especially by seed borne viruses. A study was carried out to asses the effectiveness of Positive Selection (PS) in managing seed borne potato viruses. Sprouted seed potato tubers of nine genotypes; three commercial varieties and six advanced International Potato Center (CIP) clones were screened in the field for two seasons, Field Generation Three (FG3) and Field Generation Four (FG4), respectively. In each season, experimental plots were divided into two sub-plots in which one sub-plot was planted with seed tubers sourced through Random Seed Selection (RSS) and the other with seed tuber sourced through Positive Selection (PS). Positive selection plots had low visual virus incidences, high number of tubers per hill and yield (t/ha) in both FG3 and FG4 growing seasons irrespective of the genotypes. ELISA test also revealed that Potato Virus S (PVS) (78%) was the most predominant virus...