Extent of spike shedding and stem wilting of pepper (Piper nigrum L.) in Morogoro District, Tanzania

Abstract

Background: Pepper (Piper nigrum L.) is an important spice produced by small-scale farmers in Morogoro district of Tanzania for both local and export markets. Recently, farmers have reported a decline in crop productivity due to spike shedding and stem wilting of pepper plants. The study was conducted to obtain baseline information on the extent of the disorders. Methods: An altitudinal transect survey was conducted in Morogoro district from October to November 2018. Data were collected from 216 pepper farmers through a questionnaire, focus group discussions, and field observations. Chi square tests (α = 0.05) were used to compare differences between gender, pepper cultivars by wards and yield, spike shedding and stem wilting by pepper cultivars and plant species used to support pepper vines. Fisher's exact test at (α = 0.05) was used to compare the effects of production constraints and altitude. A regression analysis was performed to explore the relationship between altitude and the incidence of spike shedding and stem wilting. Results: The majority of interviewees (69%) had observed spike shedding and stem wilting of pepper on their farms for > 3 years. Spike shedding was more prominent at 300 meters above sea level (masl, 85.7%), while stem wilting was reported by most (66.7%) farmers at 457 masl. The most affected pepper cultivar was reported to be "Babu kati" in Mtombozi (19.2% of respondents) and "Ismailia" in Mkuyuni and Kibogwa (28.9% of respondents) wards, while in Kibungo ward cultivar "Babu ndogo" (85.7% of respondents) and in Konde ward cultivar "Babu kubwa" (53.8% of respondents) were most affected. Approximately 53% of respondents reporting the disorders used Jatropha to support the pepper vines, and 93% of the farmers reported the disorders to occur during the dry season. A greater proportion of the interviewed farmers (92.1%) reported applying no measures to control spike shedding and stem wilting of pepper. Conclusions: Incidence of spike shedding and stem wilting was higher at a low altitude compared to high altitude areas. The magnitude of the disorders differed among pepper cultivars regardless of support plants species used. Poor adoption of key agronomic practices and lack of any information on control measures may be contributing to the high incidence of the disorders in the study area. The study demonstrates the extent of the problem, and provides a baseline for identifying the causal agent(s) of spike shedding and stem wilting, which in turn will allow appropriate control measures to be selected.

Morphological characterization and yield of pepper (Piper nigrum L.) types grown in Morogoro District, Tanzania

“…However, very little is known about their morphological characterization, yield in comparison to the globally known commercial cultivars, information on pedigree of pepper types grown in the district are missing and confirmation of genetic relatedness is yet needed. The pepper types have been arbitrarily given names by farmers in Swahili and Luguru tribe vernacular based on components like the striking morphological features and source of planting materials (Shango et al 2020). Similar naming of pepper types/cultivars by farmers has also been reported in other producing areas around the world including India (Mathew et al 2005(Mathew et al , 2006.…”

“…The evaluation of pepper morphological characters was conducted following a randomized complete block design (RCBD) with three replications (farmers' gardens) and four treatments which included pepper types; Babu kubwa, Babu ndogo, Babu kati and Ismailia. Since the preference and number of plants for a particular pepper type vary among farmers (Shango et al 2020), the selected farms were those containing all pepper types. The farms that fit this criteria had unequal number ranging between 5 and 15 plants for each pepper type based on respective farmer's preference, for uniformity therefore a total of five pepper plants per treatment were picked for the evaluation.…”

“…The farms that fit this criteria had unequal number ranging between 5 and 15 plants for each pepper type based on respective farmer's preference, for uniformity therefore a total of five pepper plants per treatment were picked for the evaluation. The plants were of more than four years old and trained on living supports Physic/ Purging nut (Jatropha curcas) at none specific spacing as the common traditional cropping system (Shango et al 2020). Pepper production in the study area followed smallholders' agricultural practices which included training of pepper plants on supports and weeding.…”

“…Pepper production in the study area followed smallholders' agricultural practices which included training of pepper plants on supports and weeding. Soil management practices including manure application, irrigation and drainage are not commonly practiced, thus farmers mainly rely on seasonal rainfall for moisture for the pepper plants (Maerere and Van Noort 2014;Shango et al 2020). Observations were recorded with respect to 28 characters (9 qualitative and 19 quantitative) which entail vegetative (8) and reproductive (20) traits following descriptors of pepper (IPGRI 1995) and guidelines of Distinctiveness, Uniformity and Stability (DUS) test on pepper crop (PPV and FRA 2009).…”

“…Pepper types grown in the Morogoro district of Tanzania are widely known by local names such as Babu kubwa (Komoro), Babu ndogo (Kikong'oro), Babu kati (Ya zamani), and Ismailia (Bwana shamba) (Shango et al 2020). The pepper types are believed to have originated from other places and introduced by either Missionary or Arab traders through route of domestication some years ago.…”