Development of maize genotypes for resistance to aflatoxin contamination

Transcription

1 Development of maize genotypes for resistance to aflatoxin contamination A proposal presentation in partial fulfillment of Master of Science in Plant Breeding and Biotechnology by Sammy Khakata A56/72603/2012 Department of plant Science and crop protection Faculty of Agriculture, University of Nairobi Supervisors: Dr Njoroge Kiarie Dr George N. Cheminingwa

2 Introduction Maize is staple to 90% of Kenyan population It experiences frequent aflatoxin contamination Occurs mostly in ASAL s

3 Introduction Control Strategies Biocontrol agents Appropriate crop management practices Removal of toxins Breeding for resistant maize varieties images of Aspergillus flavus in maize

4 Justification Existence of differences in resistance between field and post harvest means presence of gene systems. There is need to check if those rejected on lack of field resistance may have post harvest resistance LGB(Prostephanus truncates) and CW(Sitophilus zeamais) are major post-harvest destroyers and enhance aflatoxin accumulation. There is need to expose the resistant maize genotypes to these insects and select the best Aflatoxin resistant varieties should maintain grain quality traits such as protein,oil,ash and fiber contents. There is need to screen for these qualities so as to select good breeding materials Larger grain borer (LGB) Maize weevil

5 Objectives Broad To develop resistance to aflatoxin production in maize in Kenya Specific To quantify aflatoxin resistance and susceptibility in maize genotypes To determine relationship between insect infestation and aflatoxin production from the resistant genotypes To determine grain quality traits in resistant genotypes

6 Materials and methods For Objective inbred lines from KARI and 140 landraces will be planted and harvesting Experiment will be organized in a CRBD as a 2 factor (maize genotypes and Non inoculation or inoculation as treatments) factorial experiment with 3 replications inoculation will be by Aspergillus flavus Aflatoxin quantification will be done by Near Infra Red(NIR) spectrometer because it requires minimal sample preparation, avoids use of toxic chemicals, cost effective and it is fast. Current method of analysis(hplc) is expensive and time consuming

7 Material and methods For Objective 2 Resistant maize genotypes will be exposed to insects in the free choice method 2 large transparent plastic boxes will be placed in a room measuring 6m*6m Each box will contain inbred lines and landraces organized in a CRBD with 3 replicates Adult LGB will be released in one box and CW in another and left for one week to allow for infestation Inoculation will be done and NIR conducted for aflatoxin quantification to isolate resistant genotypes

8 Materials and methods For objective 3 Protein content will be determined by micro kjeldhals distillation method(jackson 1967) then % protein gotten by N *6.25 considering protein contains 16% Nitrogen(Adeyeye 1995) Oil, ash and fiber content will be determined by standard procedures indicated in methods of analysis of (AOAC,1990) and values expressed in %(Vogel 1980)

9 ...Materials and methods Hybridization KARI resistant Inbred lines with high grain qualities will be crossed with aflatoxin resistant landraces also with high grain qualities to produce hybrids. CRBD will be used with KARI Inbred lines and landraces as treatments with 3 replications

10 Data Analysis Data in this experiment will be subjected to Analysis of variance(anova) The Least Significant Difference(LSD) test at 5% probability level will be used to compare groups of mean

11 Expected results Inbred lines and landraces that are resistant to aflatoxin in Kenya A maize hybrid that is resistant to aflatoxin accumulation A MSc. Thesis and at least 2 published scientific papers

12 Work Plan Activity Y2Q1 JFMA 2012 Y2Q2 MJJA 2012 Y2Q3 SOND 2012 Y3Q1 JFMA 2013 Y3Q2 MJJA 2013 Y3Q3 SOND 2013 Inoculation Lab analysis Planting Weeding Crossing Harvesting Planting Data collection Data analysis Thesis writing

13 Budget Expenses Amount Land preparation and Field labor 400,000 Transport allowance, field cost and accommodation 144,000 Communication 20,000 Laptop 54,000 Stationary 40,000 Total 658,000

14 THANK YOU FOR LISTENING