Resistance spectrum of selected Manihot esculenta genotypes under field conditions
2000
A:PS
Details
Title
Resistance spectrum of selected Manihot esculenta genotypes under field conditions
Publication Date
2000
Call Number
A:PS
Summary
In Colombia, cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis is a major threat to the production of cassava (Manihot esculenta). Losses to CBB range from 12 to 90% and are most severe during wet seasons. The blight is best controlled by planting cultivars resistant to this disease. Nineteen cassava cultivars were evaluated for resistance in two edaphoclimatic zones (Pivijay (ECZ1) and Villavicencio (ECZ2)) and two crop cycles (1997 and 1998). The cultivars were planted in rows of 6 cuttings, replicated 3 times at random, and exposed to natural inoculum. Disease reaction was evaluated 4 and 7 months after planting according to a 1- to 5-scale for severity. Except in ECZ1 in 1997, where low rainfall was unfavourable for disease development, almost all plants presented symptoms. In both ECZs, disease incidence index varied greatly between cultivars and evaluations, and, for ECZ2, seasons. Correlations between field and greenhouse data for disease severity varied between years and were relatively low. However, most of the cultivars showing resistance in the greenhouse also showed resistance in the field. Several cultivars were selected for each ECZ for use in improving resistance to CBB.
Journal Citation
v.65(1):69-77, FIELD CROPS RESEARCH
Contact Information
harvest@worldveg.org
Record Appears in
Research > Published Articles