Abidin, P.E.

Andrade, M.I.

Benesi, I.

Chiipanthenga, M.

Chipungu, F.P.

Chitete, M.

Gruneberg, W.J.

Mkandawire, T.

Mwenye, O.

Pamkomera, P.

Benesi, I.R.M.

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             Introduction Sweetpotato is one of the most important food and nutrition security crops in Malawi. It is grown across  the country in different agro-ecological zones of the Agricultural Development Divisions (ADDs; Figure 1). In the Shire Valley ADD, the sweetpotato  is grown in altitude ranges of 50 to 200 m above sea level in warm to hot conditions where maximum temperatures ranges from 25 to 490C with an annual mean of 300C and under residue moisture. In the rest of the country, sweetpotato production is mostly under rain fed conditions in mid (200>700 m) and high (>1300 m) altitude of the ADDS (Figure 1) with mean annual temperatures ranging from low to medium (21 to 250C).                    Owing to the rapid population and urbanization increases that have led to high food costs, sweetpotato has become increasingly important in most low income rural and urban homesteads. The production increased from 317,714 in 1995 to 2,695,878 metric tons in 2009, while the production area increased from 60,701 to 164,255 hectares (FAO/FEWS, 1995; FEWSNET, 2009) and a productivity of 17t/ha.    Sweetpotato in Malawi is grown in diverse, small and fragmented plots and mostly in marginal environments by small-scale farmers using different varieties and cultural practices.                The ultimate goal of a sweetpotato breeder is therefore the  development of varieties which can be adapted to a range of diversified environments including those in Figure 2. In the variety development process, genotypes have to be evaluated in multi-environmental trials (MET) to ensure stable performance (Yan and Rajcan, 2002) before release.  The Department of Agricultural Research Services (DARS) in the Ministry of Agriculture and Food Security (MoAFS) and currently in partnership with Alliance for a Green Revolution (AGRA) is responsible for sweetpotato variety development in the country. One of the major breeding objectives is to develop varieties that are high yielding (>20t/ha) and tolerant to major pests (sweetpotato weevils) and diseases (viruses and alternalia). The breeding program started in 1978 where landraces Kamchiputu and Yoyera (3-7t/ha) were recommended for production in Malawi (Table 1).  Felistus Chipungu1, Thumbiko Mkandawire2, Miswell Chitete1 Ibrahim Benesi2, Pilirani Pamkomera3,  Obed Mwenye1, Erna Abidin4, Maria Andrade5, Wolfgang Gruneberg6 and Margret Chiipanthenga7   AN ANALYSIS OF GENETIC GAIN FOR SWEETPOTATO  ROOT YIELD,VARIETIES RELEASED     AND ADOPTION IN MALAWI Figure 2. Sweetpotato planted towards the end of the rainy season and in sandy soils   Figure 1: Map of Malawi showing sweetpotato agro-ecological zones in Agricultural Development Divisions (ADD) and research stations  Research stations Screening of introductions, landraces and locally acquired populations over the years have led to the release of improved varieties (Tables 1) that provide high root yields, exhibit tolerance to pests and diseases and have preferred tastes.                   The variety Kenya, bred in Tanzania (SPN/O) and introduced into Malawi through Kenya was the first improved variety released in 1988 (Moyo et al., 2001) with a yield range of 20-25t/ha (Table 1).               Recently, in partnership with AGRA, high beta-carotene varieties for a sustainable approach to vitamin A deficiency reduction have been released (Table 2) where Kaphulira and Chipika provide the highest root yield potential of 30-35t/ha. It is important however to note that in the thirty years, no variety has been released that yields beyond 35t/ha despite many potential genotypes encountered in observational and preliminary trials. While performance in terms of yield and resistance to pests and diseases are of prime importance, farmers do also prioritize taste and texture in participatory variety evaluation processes which mostly limits the release of even higher performing varieties and therefore affecting progression in genetic gain for root yield over the years.  Sweetpotato breeding and root yield genetic gain  Studies by Chipungu (2008) revealed that  in most cases, sweetpotato is planted after all other crops, and it is allocated to the poorest portion of land (Figure 2) with the full knowledge that the other crops will not give yield from such a patch. Adoption of released varieties  Name Yield t/ha Origin Remarks Zondeni (also noted in Uganda as Ejumula) 8-16 Landrace Recommended 2008, highly promoted by CIP/Irish Aid Anaakwanire BV07/028 20-25 Received as OP Ejumula (Uganda) Released 2011 Mathuthu LU06/146 20-25 OP Mogamba CIP Released 2011 Kaphulira LU06/428 30-35 OP Mogamba CIP Released 2011 Chipika LU06/527 30-35 OP Kenya (SPN/O) Released 2011 under high promotion by CIP/Irish Aid Kadyaubwelere LU06/252 25-30 OP Mafutha (RSA introduction) Released 2011 under high promotion by CIP/Irish Aid DARS has recommended three landraces and released 15 improved varieties since the start of the sweetpotato improvement program(Tables 1 and 2). In the past two decades, Malawi Government in partnerships with International Potato Centre (CIP) and NGOs disseminated these varieties to farmers. On-farm demonstrations (Figure 4) and vine multiplication (Figure 5) have also been main approaches of variety dissemination.          Of late, efforts have also been directed at disseminating orange fleshed sweetpotato (OFSP) varieties for increased adoption and utilisation and therefore a sustainable contribution to vitamin A deficiency reduction.                 In general, the high yields that have been recorded in Malawi can be attributed to the adoption of improved varieties. However, a  germplasm collection survey in 2003, revealed that Kenya was the most widely grown variety across the country and it was collected under ten different names (Chipungu, 2008). Zondeni, an orange fleshed variety is the second widely grown cultivar which along with the newly released OFSP varieties is under high promotion by International Potato Centre facilitated by Irish Aid. It is also important to note that farmers grow the improved varieties along with their own landraces an indication that apart from involving them in variety selection, there is also a strong need for civic education to increase adoption and utilisation of the released varieties for high yields and improved food and nutrition security.    Conclusion Through the breeding program, three landraces and 15 improved varieties that yields up to 35t/ha have been released. Potential to identify varieties that yield >35t/ha is high if varieties are released for value addition. The improved varieties have contributed to increased productivity from 3-5t/ha  (1995) to 12-17t/ha (current)  at farm level.    References Chipungu FP. 2008. Ethno-botanic and genetic variations among sweetpotato accessions grown in Malawi. Ph D thesis. The University of Malawi, Chancellor College, Zomba  FEWS/MoAFS. 1995 and 2009. FAO/WFP crop and food supply assessment mission to Malawi  Yan W and I Rajcan. 2002. Biplot evaluation of test sites and trait relations of soybean in Ontario. Crop Science 42:11-20.  Acknowledgement The authors would like to sincerely acknowledge Governments of Malawi and Ireland (through CIP), AGRA and all partners who have contributed to sweetpotato variety development and dissemination in Malawi. Figure 3: Sweetpotato on station evaluation trial at Bvumbwe Agricultural Research Station Key: AVRDC= Asian Vegetable Research and Development Centre; CIP= International Potato Centre; IITA= International Institute of Tropical Agriculture; OP= Open pollinated  Varieties Yield (t/ha) Origin Remarks Yoyera  3-7 Landrace Recommended in 1980s, rarely grown Kamchiputu 3-7 Landrace Recommended in 1980s, rarely grown Kenya (SPN/O)  20-25 Tanzania  Released in 1988, widely grown. Lunyangwa 20-25 Local bred Released in 1990, low adoption Kakoma (TIS 3017) 25-35 IITA Released in 1993, low adoption  Semusa (Cemsa 74-288) 25-35 CIP Released in 1999, being adopted Mugamba (Mogamba) 20-25 CIP Released in 1999, being adopted Tainoni (Tainon 57) 18-20 AVRDC Released in 1999, low adoption  Salera (CIP1941 121) 20-25 CIP Released in 2002, low adoption Sakananthaka (LU96/303) 18-20 OP (Malawi) Released in 2008, Low adoption Nyamoyo (BV07/008) 8-35 OP LU96/374 Released 2011, new release Sungani (BV07/016) 30-35 OP Semusa Released 2011, new release Table 1. Improved and released sweetpotato varieties in Malawi  Further variety development evaluation trials which are done both under research stations and on-farm (Figures 1 and 3) conditions led to the release of more varieties (Tables 1 and 2).  Table 2: Recently released orange fleshed sweetpotato varieties of Malawi Key: OP= open pollinated; CIP= International Potato Centre; RSA= Republic of South Africa Figure 5: On-farm vine multiplication Figure 4: On-farm variety demonstration Figure 6: Youth in OFSP chips enterprise The promotion of orange fleshed sweetpotato has taken an extra mile as apart from on-farm demonstration and dissemination of vines, farmers are trained on the utilisation modes and value addition of OFSP which include young men who are engaged in chips enterprise (Figure 6). In partnership with Universal Industries, a biscuit and crisp processing company, Zondeni (Figure 7) was one of the best for crisp making.  Figure 7: Variety Zondeni best for crisp Efforts by breeders have been directed at developing varieties of high root yield for effective contribution to food insecurity reduction. Notably among the highest yielding varieties (30-35t/ha) are two introductions; Kakoma (1994) and Semusa (1999) and most recently varieties developed from locally generated populations; Nyamoyo and Sungani released in 2011 (Table 1). Figure 3: Farmers participating in evaluation for agronomic and taste preference In Malawi, the process of variety release has been designed to meet the specific requirements of different farmers through multi-location on-farm participatory evaluation (Figure 3). Different varieties have therefore been released that provide choices to farmers in terms of agronomic suitability and taste preference.   1Bvumbwe Agricultural Research Station, PO Box 5748, Limbe, 2Chetedze Research Station, PO Box 258, Lilongwe, Makoka Research Station,  P/Bag 1, Thondwe, Malawi, 4International Potato Centre, Malawi, C/O IITA, P O Box 30258, Lilongwe 3, Malawi, 5International Potato Centre,   Maputo Mozambique, 6International Potato Centre, Lima Peru, 7Kasinthula Research Station, Chikhwawa, Malawi Correspondence: Felistus Chipungu (Ph D); Bvumbwe Agricultural Research Station, PO box 5748, Limbe Malawi; email: felichipungu@yahoo.com 

An analysis of genetic gain for sweetpotato root yield, varieties released and adoption in Malawi.

https://cgspace.cgiar.org/bitstream/10568/73202/3/78259.pdf

An analysis of genetic gain for sweetpotato root yield, varieties released and adoption in Malawi.

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