Relationship between Taro Leaf Blight (Phytophthora Colocasiae) Disease Resistance and Agronomic Traits of Kenyan and Pacific - Caribbean Taro (Colocasies Esculenta) Accessions

Abstract

— Taro (Colocasia esculenta) is an important food crop whose production is declining gradually leading to widespread genetic erosion. Despite the limited commercial development, it is important in diet of many in the developing countries. Its corms are baked, roasted, or boiled and the leaves are frequently eaten as vegetable. It is an important source of vitamins, especially folic acid. Phytophthora colocasiae is currently one of the most devastating fungal taro pathogen whose control has relied majorly on use of systemic fungicides which are not environmental friendly. Accessions resistant to taro leaf blight (TLB) can grow without any or fewer fungicide applications. Resistance level of accessions differ largely based on genetic composition, origin and agronomic practices. This fact was the reason for the evaluation of taro accessions from Pacific - Caribbean and Kenya for resistance to TLB under two different trials. Thirteen taro accessions were obtained from previously imported taro from different Pacific - Caribbean and thirteen from six counties in Kenya (Siaya, Kisumu, Busia, Uasin Gishu and Kakamega). They were established in Kakamega, county of Kenya. All the recommended practices were followed for raising a plant except plant protection. CRD was used with three replications. Data collection was started two months of establishment and at one-month interval for five months. Number of suckers and leaves were obtained monthly while corm weight was obtained at harvesting when the plants were seven months old. The disease was scored on a severity scale of 0-9 scale.Resistance was calculated by subtracting the already obtained percent disease severity from 100%.Marked difference in disease resistance was noticed among accessions from different regions and small differences from same region.Disease resistance ranged between 58.27% - 89.73% for Kenyan and Pacific – Caribbean taro respectively with BL/SM/128 from Samoa portraying the highest resistance of 89.73%.Correlation between TLB resistance and number of suckers and total leaf area under field study revealed a negative co-efficient.These differences can be used in breeding studies for disease-resistanceand high yield.