Preliminary observations on the response of soybean genotypes to Frogeye disease under natural conditions in Ebonyi State, Nigeria

Abstract

Frogeye leaf spot (FLS) of soybean (Glycine max L.) is an important disease that causes significant seed yield loss in warm, humid regions  of the world. The study was conducted with the objective to assess the response of soybean to source of FLS at the Teaching and  Research Farm, Federal College of Agriculture, Ishiagu, Ebonyi State, Nigeria during 2021 late cropping season. Eight soybean genotypes  were screened against FLS under natural condition. The experiment was laid out in a randomized complete block design and replicated  three times. The data collected were disease incidence, severity and agronomic performance which were subjected to analysis of variance  and the means were separated using Tukey at P<0.05. The results revealed that genotype TGX-1904-6F had the highest disease  incidence (46.67%), followed by TGX-1989-19F (18.33 %) while TGX-1987-62F (5.00 %) had the least. Similarly, the result of the disease severity ranged from 1.00-3.77. TGX-1904-6F (3.77) had the highest, followed by SCSL-01 (2.47) while TGX-1987-10F (1.00) had the least.  The result of resistant levels indicates that one soybean genotype (TGX-1987-10F) was highly resistant, five were resistant (TGX-1951-3F, TGX-1448-2E, TGX-1987-62F, TGX-1989-19F and TGX-1835-10F), one genotype was moderately resistant (SCSL-01) and one moderately  susceptible (TGX-1904-6F). Five fungi organisms belonging to four genera were isolated from eight soybean seeds which includes Aspergillus niger, Aspergillus flavus, Fusarium oxysporum, Penicillium species and Curvularia species. Aspergillus flavus (38.30 %) had the  highest percentage of occurrence while Curvularia species (2.13 %) had the least. The study recommended that the resistant  genotypes could be further planted in other agro ecological zone to determine resistant genotypes against frogeye leaf spot disease in  soybean.