Evaluation of Methods for Screening Taro (Colocasia Esculenta) Genotypes for Resistance to Leaf Blight Caused by Phytophthora Colocasiae.

Abstract

Three screening methods; spray-on, stick-on and leaf-disc were compared to reliably identify moderate or partial resistance against taro leaf blight caused b/Phytophthora colocasiae. Each of the method was tested on susceptible, moderately resistant and resistant cultivars at three, four and five months of plant age. No significant differences (P > 0.05) were observed among inoculation methods and plant ages for the area under disease progress curve (AUDPC) of the susceptible and resistant cultivars. Using the leaf-disc method, twenty-six elite taro genotypes from third recurrent breeding cycle were screened and six moderately resistant genotypes, which are likely to be associated with polygenic and durable resistance were advanced to the fourth breeding cycle for further evaluation.