Effect of Different Doses of Irradiation on the Germination of Varieties of Maize Developing against the Fall Armyworm in the Central African Republic

Abstract

Maize is a major crop feeding 80% of the population of the Central African Republic (CAF). However, the country is not yet self-sufficient in its maize need and continues to rely partially on imports. Exacerbating this situation is the recent invasive spread of the fall armyworm attributed to change in weather patterns since 2016 which has been decimating the crop leading to drastic yield losses. Various control measures continue to be tested globally for the control of FAW, including chemical control, biological control using microbial organisms and predatory insects that attack FAW, use of genetically modified crops with Bt genes, and integrated pest management. However, the use of developing genetic resistance in maize against the pest remains under-explored. We focused research on initiating a mutation breeding effort in maize in CAF. The goal of this experience is to determinate the optimal dose from radio-sensitivity test of CMS8704 (100 Gy, 200 Gy, 300 Gy, 400 Gy and 500 Gy), CMS 2019 (100 Gy, 200 Gy, 300 Gy, 400 Gy and 500 Gy), CMS 8501 (100 Gy, 200 Gy, 300 Gy, 400 Gy and 500 Gy) and local ecotypes (100 Gy, 200 Gy, 300 Gy, 400 Gy and 500 Gy). 200 seeds are bulk to irradiation with different doses (100 Gy, 200 Gy, 300 Gy, 400 Gy and 500 Gy). The test of germination is carried out on 200 seeds four varieties. The treated seeds are sown at equal depths in a tray filled with soil/compost or can as well sow in natural condition on the field just to assure that the soil surface is flat, and the treated seeds are sown at equal depth containing the five treatments in rows of 200s seed each for one control and each treatment.  Per assay three replicates are performed, one tray per replicate.  Fourteen days after sowing, the seedling height and survival is measured to determine the Growth Reduction Value 50 or GR50.  All seeds from different doses (CMS-20 19, CMS87 04 and the Local ecotype) were germinated from different doses (100Gy, 200Gy and 300Gy) and did be presented   the symptom of FAW. However, for the CMS85 01, all seeds from different doses (100Gy, 200Gy, 300Gy; 400Gy and 500Gy) were germinated as the control, but the major of plants are attacked by the FAW (Fall Armyworm).