EVALUATION OF COWPEA GENOTYPES FOR THEIR REACTIONS TO STEM ROT INDUCED BY RHIZOCTONIA SOLANI (KUHN)

Abstract

Rhizoctonia solani is one of the pathogens that infect cowpea causing stem and root rot, seedling decay and damping - off complex which result in low yield. This study aims to evaluate some cowpea genotypes for their reactions to Rhizoctonia solani.

Six improved cowpea varieties (SAMPEA 7, SAMPEA 8, SAMPEA9, SAMPEA 10, SAMPEA 11 and SAMPEA 12) two accessions(IAR–00–1074 and IAR–07–1050) and four local varieties (Biu local, Maifarinhanci, Kanannado and Dansokoto) were evaluated in the glasshouse and on the field for their reaction to R. solani infection. R.solani was multiplied on millet grain and used to inoculate the cowpea genotypes in both glasshouse and field studies. Symptoms of disease incidence and severity were observed on all the 12 cowpea genotypes inoculated with R. solani. In the glasshouse, SAMPEA 10recorded the highest incidence (100 %) and SAMPEA 9 recorded the highest severity (62.86 %). In the field however SAMPEA 10recorded the highest incidence (75.41 %) and severity (66.19 %).Dansokoto recorded the lowest incidence (8.33 and 21.67 % for glasshouse and field respectively) and severity (6.67 and 17.14 % for glasshouse and field respectively). Correlation analysis showed that stem rot incidence and severity significantly resulted in reduced number of pods and grain yield. It is thus concluded that the local varieties evaluated are more resistant to the disease and as such breeding program should focus on improving the desired characteristics of the local varieties.