Tolerance and resistance of maize hybrids to maize streak virus in Uganda

Abstract

Maize streak virus disease is the most important disease of maize in Uganda. On susceptible varieties, yield losses of 90% have been observed. Many of the varieties private seed companies brought into the country claiming to be resistant to the disease have succumbed. It is therefore, mandatory to screenfor MSV resistance in local and introduced maize varieties. A study was initiated to ascertain the resistance levels of the hybrids from private seed companies for their consideration of release in Uganda. Results obtained showed that out of 20 hybrids evaluated, two were resistant, fourteen tolerant and four susceptible. However, most hybrids with high incidence had high severity scores and this was positively correlated (r=0.66). Some hybrids like PAN 33 despite being resistant to MSV had other shortcomings like susceptibility to gray leaf spot and ear rots. These constraints are likely to affect its utilization in Uganda as is the case with SC 625 which failed to be released because of its susceptibility to ear rots.