Benefits of maize resistance breeding and chemical control against northern leaf blight in smallholder farms in South Africa

Show simple item record Berger, David Kenneth Mokgobu, Tumisang De Ridder, Katrien Christie, Nanette Aveling, T.A.S. (Terry) 2021-08-30T13:53:10Z 2021-08-30T13:53:10Z 2020-11-26
dc.description.abstract Maize underpins food security in South Africa. An annual production of more than 10 million tons is a combination of the output of large-scale commercial farms plus an estimated 250 000 ha cultivated by smallholder farmers. Maize leaves are a rich source of nutrients for fungal pathogens. Farmers must limit leaf blighting by fungi to prevent sugars captured by photosynthesis being ‘stolen’ instead of filling the grain. This study aimed to fill the knowledge gap on the prevalence and impact of fungal foliar diseases in local smallholder maize fields. A survey with 1124 plant observations from diverse maize hybrids was conducted over three seasons from 2015 to 2017 in five farming communities in KwaZulu-Natal Province (Hlanganani, Ntabamhlophe, KwaNxamalala) and Eastern Cape Province (Bizana, Tabankulu). Northern leaf blight (NLB), common rust, Phaeosphaeria leaf spot, and grey leaf spot had overall disease incidences of 75%, 77%, 68% and 56%, respectively, indicating high disease pressure in smallholder farming environments. NLB had the highest disease severity (LSD test, p<0.05). A yield trial focused on NLB in KwaZulu-Natal showed that this disease reduced yields in the three most susceptible maize hybrids by 36%, 71% and 72%, respectively. Eighteen other hybrids in this trial did not show significant yield reductions due to NLB, which illustrates the progress made by local maize breeders in disease resistance breeding. This work highlights the risk to smallholder farmers of planting disease-susceptible varieties, and makes recommendations on how to exploit the advances of hybrid maize disease resistance breeding to develop farmer-preferred varieties for smallholder production. SIGNIFICANCE : • Northern leaf blight, grey leaf spot, Phaeosphaeria leaf spot and common rust diseases were widespread in KwaZulu-Natal and Eastern Cape smallholder maize fields where fungicides were not applied. • NLB was the most severe maize leaf disease overall. • NLB caused maize leaf blighting, which reduced grain yields by 36–72% in susceptible maize hybrids. • Maize resistance breeding has produced locally adapted hybrids that do not have significant yield losses under NLB disease pressure. en_ZA
dc.description.department Biochemistry en_ZA
dc.description.department Forestry and Agricultural Biotechnology Institute (FABI) en_ZA
dc.description.department Genetics en_ZA
dc.description.department Microbiology and Plant Pathology en_ZA
dc.description.department Plant Production and Soil Science en_ZA
dc.description.librarian am2021 en_ZA
dc.description.sponsorship Department of Agriculture, Forestry and Fisheries Research Technology Fund through the National Research Foundation of South Africa; USAID through the University of California Davis Research and Innovation Fellowship for Agriculture. en_ZA
dc.description.uri en_ZA
dc.identifier.citation Berger DK, Mokgobu T, De Ridder K, Christie N, Aveling TAS. Benefits of maize resistance breeding and chemical control against northern leaf blight in smallholder farms in South Africa. South African Journal of Science 2020;116 (11/12), Art. #8286, 7 pages. 10.17159/sajs.2020/8286. en_ZA
dc.identifier.issn 0038-2353 (print)
dc.identifier.issn 1996-7489 (online)
dc.identifier.other 10.17159/sajs.2020/8286
dc.language.iso en en_ZA
dc.publisher AOSIS Open Journals en_ZA
dc.rights © 2020. The Author(s). Published under a Creative Commons Attribution Licence. en_ZA
dc.subject Fungicide en_ZA
dc.subject Disease resistance breeding en_ZA
dc.subject Common rust en_ZA
dc.subject Maize en_ZA
dc.subject Grey leaf spot (GLS) en_ZA
dc.subject Northern leaf blight (NLB) en_ZA
dc.subject Phaeospaeria leaf spot (PLS) en_ZA
dc.subject South Africa (SA)
dc.title Benefits of maize resistance breeding and chemical control against northern leaf blight in smallholder farms in South Africa en_ZA
dc.type Article en_ZA

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