Development of drought tolerant maize hybrids adaptable to climate change: A worthwhile and enriching experience

Dr. Abimbola  Oluwaranti, Obafemi Awolowo University, Ile-Ife, Nigeria

Cohort 2 CIRCLE Visiting Fellow

The main focus of my CIRCLE research has been to develop drought tolerant maize varieties adaptable to the effects of climate change.  At the onset of my CIRCLE research fellowship, under the supervision of Dr. Richard Edema, the coordinator of Central and East African Regional M.Sc. (Plant Breeding and Seed Systems) program, of the Department of Agricultural Production, Makerere University, Uganda, we engaged all necessary stakeholders. This included Maize breeders from the Cereal Research Program of National Crop Resources Research Institute (NaCRRI), Namulonge, Kampala, Uganda who helped with the provision and field evaluation of drought tolerant maize parental lines. Developing improved varieties of crops conventionally in the field takes a long time and the improvement is not stable due to the influence of the environment. However, the Cereal Research Program already has an existing maize breeding program under the leadership of the Dr. Godfrey Asea, a maize breeder who is also the Director of the Institute. Dr. Asea willingly directed the farm technicians to provide available drought tolerant maize inbred/parental lines to be used for phenotypic selection and molecular characterization. This meant we were able to develop drought tolerant maize hybrids which will be released to farmers to enhance food security in the face of climate change.

Field evaluation and phenotypic selection

Sixty-eight maize inbred lines were planted for evaluation in four different locations in Uganda and Kenya under different conditions; Optimum and Low-Nitrogen conditions (NaCCRI research field, Namulonge and Serere in Uganda), Drought stress (Kasese, Uganda and Kiboko, Kenya).

Measuring chlorophyll content (a drought tolerant trait) with Photosynq equipment at the NaCRRI experimental field, Namulonge, Uganda

Molecular characterization of the drought tolerant inbred lines 

In addition to evaluation in the field, genomic DNA was extracted from the sixty-eight maize inbred lines. The extracted DNA was then quantified with a NanoDrop Spectrophotometer to ensure that it was pure. Nineteen Simple Sequence Repeats (SSRs) molecular markers already linked to the gene controlling drought tolerance in previous studies were used for the Polymerase Chain Reaction (PCR). An ARKTIK 96 well thermal cycler was used for the PCR amplification of the DNA after which the PCR reaction mixtures undergo GEL Electrophoresis to determine the location of the genes controlling drought on the chromosomes of the maize.  This laboratory work has led to the selection of drought tolerant parental lines which could have taken several seasons of field evaluations before this selection could take place.

Extracting, quantifying and amplifying genomic DNA at the Biotechnology Laboratory

Research Outputs

The identified maize inbred/parental lines will be used to develop drought tolerant maize hybrids in November/December for the agro-ecologies of Uganda. These will later be released to farmers in these areas for better grain yield under drought conditions. The research findings of the phenotypic field evaluations and molecular works have been written up for presentation at the forthcoming 11th International conference of the African Association of Remote Sensing of the Environment (AARSE) and National Agriculture Research Organization-Makerere (NARO-MAK) Joint Agricultural Dissemination Conferences in October and November respectively.

My experience in the biotechnology laboratory has been a worthwhile and enriching one and I have acquired new molecular laboratory skills. These skills will lead to further training on “Molecular laboratory techniques” at the University of Cambridge, UK. My appreciation goes to my Supervisor on this program and the CIRCLE management team for supporting my attendance at the training. Indeed my molecular laboratory skills and capacity on Climate Change impacts research has improved tremendously through this program, kudos to the CIRCLE fellowship!!!