Screening of 20 Accessions of Sesame (Sesamum indicum) for Resistance to Cercospora Leaf Spot Disease
S. E. Udo
Department of Biological Science, Cross River University of Technology, P.M.B. 1123, Calabar, Nigeria
E. A. Okon *
Department of Biological Science, Cross River University of Technology, P.M.B. 1123, Calabar, Nigeria
T. O. Akwaji
Department of Biological Science, Cross River University of Technology, P.M.B. 1123, Calabar, Nigeria
H. E. Etta
Department of Biological Science, Cross River University of Technology, P.M.B. 1123, Calabar, Nigeria
E. O. Peter
Department of Biological Science, Cross River University of Technology, P.M.B. 1123, Calabar, Nigeria
*Author to whom correspondence should be addressed.
Abstract
Aims: Twenty accessions of sesame (Sesamum indicum) were screened for resistance to Cercospora leaf spot disease.
Sample: Twenty accessions of Sesamum indicum were used for the study. The sesame accessions were obtained from various localities and raised in a green house.
Study Design: Three to four seedlings were initially transplanted per hole and later thinned to two after establishment and arranged in a complete randomized design (CRD).
Place and Duration of Study: Cultivation of seedlings and transplantation were all carried out at a standard green house of the Molecular Biology Laboratory located at 124 MCC Road, Calabar, Cross River State of Nigeria in August, 2013.
Methodology: Isolation was made from leaves of diseased host plants. Test plants infected leaves with characteristic anthracnose symptoms were collected from the field. They were thereafter, subjected to pathogenicity test with Cercospora sesami to determine their levels of resistance to this debilitating pathogen.
Results: Plant height was strongly positively related to seed size (r = 0.85) and number of branches (r = 0.72) and had a significant correlation with the number of seeds per plant (r = 8.60). Correlation coefficient studies revealed that six out of the eight parameters were significantly (P = 0.05) correlated.
Conclusion: The results obtained indicate that accessions from Adagum and Ndok were immuned or highly resistant to Cercospora leaf spot (CLS) disease with disease severity of 0 (zero). Also, collections from Ogoja, Akim Market and Watt Market were resistant to CLS diseases with disease severity of 1.621, 1.820 and 1.545 respectively. Nwang, Mbube East, Bansara, Obudu Market, Obanliku Market, Gboko Market, Ukpa Market, Yahe Market and Ekpugrinya Market and Okpoma Market were either moderately susceptible or susceptible to CLS disease according to their mean disease severities.
Keywords: Sesame accessions, Cercospora leaf spot disease (CLS), pathogenicity test, disease severity, morphological characters, correlation coefficient