Screening for Aflatoxin Resistance in Maize Tengan, K. Martin Luther Maize Improvement - CSIR-CRI

Research Team  Tengan, K. Martin Luther MSc Maize Breeder Leader  Kwadwo, Obeng-Antwi PhD Senior Maize Breeder  Emanuuel Moses PhD Plant Pathologist  Manfred, B. Ewool MSc Maize Breeder  Frank, C. Danso BSc Agronomy  Robert Kankam Chief Technical Officer  Joseph, K. Amponsah Chief Technical Officer  Charles, K. Adabre Principal Technical Officer  Edward Abugbilla Principal Technical Officer  Francis Ayuebonteng Principal Technical Officer

Introduction  Aflatoxins are toxic metabolites produced by certain fungi in/on foods and feeds.  They are probably the best known and most intensively researched mycotoxins in the world.  Aflatoxins have been associated with various diseases, such as aflatoxicosis, in livestock, domestic animals and humans throughout the world

 The occurrence of aflatoxins is influenced by humid warm conditions, or stressed conditions such as drought.  Extent of contamination varies with geographic location, agricultural and agronomic practices, and the susceptibility of commodities to fungal invasion during pre-harvest, storage, and/or processing periods.

 Aflatoxins have received greater attention than any other mycotoxins due to their demonstrated potent carcinogenic effect in susceptible laboratory animals and their acute toxicological effects in humans

 Raw Agricultural products: 1. In crops in the field prior to harvest 2. Harvested products 3. Grain in storage Plate 3 Plate 2 Plate 1

 Processed Foods:  Milk and milk products i.e. non-fat dry milk cheese yoghurt  Eggs  Meat products

Justification  The Food and Agriculture Organization estimates that aflatoxins contaminate 25% of agricultural crops worldwide (Smith et al 1994).  Ingestion of higher doses of aflatoxin can result in acute aflatoxicosis, which manifests as hepatotoxicity or, in severe cases, fulminant liver failure (Fung and Cark 2004).

Justification cont’d  Aflatoxin concentration in contaminated maize samples ranged from 24 to ng g − 1 in Benin, from 0.4 to ng g − 1 in Ghana, and from 0.7 to ng g − 1 in Togo (James et al., 2007)  Average aflatoxin levels in samples of maize from Ejura-Sekyedumasi, North Kwahu,and Nkoranza were ppb, ppb and ppb respectively (Akrobortu et al, 2008

 There is therefore the need to develop maize varieties that can respond well to the negative effects of field and storage fungi on maize and maize products.

Main objectives  Develop aflatoxin resistant maize varieties for Ghanaian farmers to ensure food safety in maize and for consumers of maize products.  Enhance the potential of maize as a commercial and export crop.

Specific objectives  Screen for aflatoxin resistant lines in maize.  Identify lines that are resistant to field and storage fungi.  Develop varieties (hybrids, top crosses) from resistant lines.

Methodology  Obtained accessions from IITA:  72 intermediate maturing white kernel accessions  40 intermediate maturing yellow kernel accessions  Design: RCBD  Rows/plot: 1, (13 hills/row)  Replications: 2

 Laboratory Screening (in collaboration with Plant Health Division)  Seeds plated on blotters in a petri-dish for seven days.  Examination of seeds for field and storage fungi.

Plates 4 and 5: Field Screening Plate 4 Plate 5

 Plate 6 Plate 7 Plate 8 Plate 9 Plate 6-9: Acceptable cobs after field screening

Parameters Assessed  Field :  Seedling vigor  Days to 50% silking  Days to 50% anthesis  Husk cover score (1-5)  Ear aspect score (1-5 )  Laboratory investigation:  Field and storage fungi

Results Table 1: Husk cover and ear aspect scores (1-5) of white kernel accessions Entry No.Accession No.Kernel colourHusk cover scoreEar aspect score 109C10927B white33 209C10929B,,21 309C10903B,,22 510C112601B,,43 610C112603B,,11 810C112863B,,33 910C112861B,, C112865B,, C112881B,, C112869B,, C112871B,, C112875B,, C112877B,,11

Entry No.Accession No.Kernel colourHusk cover scoreEar aspect score 1810C112879B white C112879B,, C112883B,, C112885B,, C112887B,, C112889B,, C112891B,, C112895B,, C112899B,, C112901B,, C112905B,, C112909B,, C112911B,, C112913B,, C112921B,, C112923B,,21

Entry NoAccession No.Kernel colourHusk cover scoreEar aspect score 4110C112925B white C112927B,, C112931B,, C112933B,, C112937B,, C112939B,, C112945B,, C112947B,, C112953B,, C112955B,, C112957B,, C112963B,, C112967B,, C112973B,, C112975B,, C112977B,,11

Entry NoAccession No.Kernel colourHusk cover scoreEar aspect score 691OC112981B white C112983B,, C112985B,,21 72OBA SUPER 1,,22

Table 2: Husk cover and ear aspect score (1-5) of yellow kernel accessions Entry No.Accession No.Kernel colourHusk cover scoreCob aspect score 110C112585B yellow33 210C112587B,,43 710C112599B,,11 810C112575B,,44 910C112577B,, C112579B,, C112581B,, C112587B,, C10869B,, C112811B,, C112813B,, C112823B,, C112829B,,21

Entry No.Accession NoKernel colourHusk cover scoreCob aspect score. 2510C112831B yellow C112833B,, C112835B,, C112841B,, C112843,, C112849B,, C112851B,, C112853B,, C112855B,, C112857B,,11 39Golden crystal,,23 40Golden jubilee,,33

 Laboratory investigation revealed 5 promising accessions: 1. 10C112605B white 2. 10C112873B white 3. 10C112841B yellow 4. 10C112851B yellow 5. 09C10869B yellow

Plan for 2012  Repeat field screening at 3 locations (Fumesua, Ejura and Wenchi)  Laboratory screening of selected accessions

Acknowledgements  Mr. Tom Gambrah (Premium Foods Ltd.)  Staff of CSIR-CRI Maize Improvement Program (Fumesua)  Staff of CSIR-CRI Plant health (Pathology) section (Fumesua )

Thank you