Assessment of Disease Intensity and Evaluation of Enset Clones against Bacterial Wilt (<I>Xanthomonas campestris pv. Musacearum</I>) in Tikur Inchini and Jibat Districts of West Shewa, Ethiopia

Abstract

Enset ( Ensete ventricosum Welw. Cheesman) is an important staple food crops in Ethiopia, which is widely cultivated in Southern and South western parts of the country. However, its production has been threatened by one of the devastating bacterial disease caused by Xanthomonas campestris pv. musacearum (Xcm) in enset cultivated areas of the country. The management of Enset Bacterial Wilt (EBW) is important to maximize the crop's yield. Therefore, the present investigation is to determine the disease intensity (prevalence and incidence) of EBW in enset growing areas of Tikur Inchini and Jibat districts of West Shewa, Ethiopia and to evaluate the field grown enset clones for resistance/tolerance to EBW using pot culture condition. Field survey of EBW disease was carried out in the main growing season during September-November, 2012. The disease assessment was made in the enset cultivated fields of selected localities in both districts. The EBW infection was recorded in different levels in both districts. A total of 75 enset cultivated fields were assessed from Tikur Inchini district, of which, 67 fields were affected with different levels of EBW disease prevalence (89.3%). The highest incidence (27%) of EBW was recorded in Waldo Hindhe locality and the lowest incidence was recorded in Homi Hane locality (14 %). From Jibat district, a total of 75 enset cultivated fields were assessed, of which, 65 fields were affected with different levels of disease prevalence (86.7%). The incidence of EBW was recorded highest in Munyo Abayi locality (25%) and the lowest incidence was recorded in Munyo Witate locality (14%). This data indicated that the disease was widely distributed with a very destructive incidence in survey areas of Tikur Inchini and Jibat districts. To evaluate the field grown enset clones for resistance/tolerance to Xcm, twenty number of enset clones collected from both the districts were assessed, using artificial inoculation under pot culture condition. The relative susceptibility of the cultivars to EBW was evaluated three months after inoculation based on wilt incidence. All Xcm inoculated enset clones expanded disease symptoms to different intensity levels after 15 to 30 days inoculation. The varieties of the disease frequency were variable ranging from 19.3 to 100%. Out of the 20 enset clones, only 6 enset clones confirmed a mean infection incidence less than 50 percent. The present investigation displays that the enset genetic copies fluctuate enset bacterial wilt by their reaction. After 30 days of introduction of inoculation, the enset clones 'Warke Bidu', 'Awenyi', and 'Kekar' showed 100 % disease symptoms. The disease symptom was detected from 'Meziya', 'Hiniba', 'Bedadet' and Warke Dima between 21 and 30 days successive inoculation. The remaining enset clones were relatively resistant/tolerant after inoculation of Xcm. Among all, 'Meziya' was found to have the lowest percentage of disease incidence (19.31%) followed by 'Hiniba' (30.18%) and 'Bedadet' (34.26%). Based on the results, none of the enset clones had resistance to Xcm. The results indicated that the enset clones, 'Meziya', 'Hiniba', 'Bedadet' and 'Warke Dima' have exhibited better resistant/tolerant clones to the bacterial wilt, under artificial inoculation conditions and these enset clones should be considered as most tolerant/resistant clones to the pathogen which could be used as a bacterial wilt management component. The results of the study indicated that the use of resistant/tolerant enset clones is one of the best approaches in the management of EBW, cheaper to the farmers and safer to environments. Hence, a resistant and tolerant outcome of the enset clones confirmed by the wilt pathogen should be further assessed in contrast to a great number of Xanthomonas campestris pv. musacearum , isolates in field conditions.