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Exploring the yield gap of orange-fleshed sweet potato varieties on smallholder farmers' fields in Malawi.

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Title Exploring the yield gap of orange-fleshed sweet potato varieties on smallholder farmers' fields in Malawi.
 
Creator Vugt, D. van
Franke, A.C.
 
Subject SWEET POTATOES
BOUNDARIES
PRODUCTION
CURCULIONIDAE
PLANTING
 
Description Orange-fleshed sweet potato (OFSP) can contribute to combating vitamin A deficiency and establishing more resilient cropping systems in sub-Saharan Africa. There is limited understanding of the factors that affect yield and quality of OFSP on smallholder farmers’ fields. This study aimed to assess the performance of six OFSP varieties, identify factors limiting productivity and explore options to close the gap between actual and attainable OFSP yields on fields of smallholder farmers. Data were collected in the 2015/16 growing season from 221 on-farm variety demonstrations in seven districts in Central and Southern Malawi. Dependent variables of interest included crop establishment, vine yields, storage root formation, root yields, percentage of marketable root yield, and weevil infestation. Using linear mixed models, a range of biophysical, climatic, management and socio-economic factors and variables was used to identify associations with these dependent variables. The root yield gap was explored using a multivariate boundary line model to identify the most yield limiting factors. Results show a large variability across farmers’ fields and a wide range of interacting factors affecting the variables of interest. Varieties Chipika and Kadyaubwerere attained good yields and were preferred by farmers in terms of taste. Varieties Zondeni and Anaakwanire gave a poor root yield, but a good vine yield. Timely planting is crucial to attain good root yields by making better use of the available rainfall. There was a varietal effect on weevil infestation and Kaphulira was most affected. Weevil control is required for market-oriented producers to enhance the percentage of marketable roots. The average attainable fresh root yield ranged from 18 t ha for Zondeni to 32 t ha for Mathuthu, against actual yields of 5–9 t ha. Elevation, planting date, rainfall and crop establishment could explain only 28 percent of the average yield gap, while 49 percent was explained for Mathuthu. Other factors that may explain the yield gap, but were not included in the model are: tillage methods and soil nutrient limitations. Male host farmers received better quality cuttings and planted in better soil moisture conditions, resulting in better establishment and vine yields. OFSP productivity can be enhanced through gender-sensitive extension, by ensuring male and female farmers can plant clean planting material of a suitable variety early in the rainy season. This requires additional efforts in vine multiplication of the required variety prior to the onset of the rains.
United States Agency for International Development
Peer Review
 
Date 2018-06-05T15:54:12Z
2018-06-05T15:54:12Z
2018-05
 
Type Journal Article
 
Identifier Van Vugt, D.; Franke, A.C. 2018. Exploring the yield gap of orange-fleshed sweet potato varieties on smallholder farmers' fields in Malawi. Field Crops Research. (Netherlands). ISSN 0378-4290. 221:245-256.
0378-4290
https://hdl.handle.net/10568/93044
 
Language en
 
Format 245-256
 
Source Field Crops Research