TITLE:
Assessing Reactions of Genetically Improved and Local Cassava Varieties to Cassava Mosaic Disease (CMD) Infection in a Savannah Region of the DR-Congo
AUTHORS:
Marcel Muengula-Manyi, Lyna Mukwa, Kabwe K. Nkongolo, Patrick Tshilenge-Djim, Stephan Winter, Claude Bragard, Adrien Kalonji-Mbuyi
KEYWORDS:
Cassava Mosaic Disease; Local Cassava Varieties; Genetically Improved Cassava Varieties; AUSiPC; AUDPC; Disease Index; DR-Congo
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.4,
April
17,
2013
ABSTRACT: The responses of eight genetically improved and eight
local cassava varieties to cassava mosaic disease (CMD) were evaluated under
field conditions at two sites, in Eastern Kasa?, region of the DR-Congo). The
varieties were planted using randomized complete block design with three
replications. The rate of cuttings sprouted varied significantly from variety
to variety and from location to location. Local varieties were severely
infected than improved varieties throughout the trial period. In general,
the level of CMD incidence for genetically improved varieties was below 15%
while it reached 100% for the local cassava varieties six months after planting
(MAP). This trend was also observed for the CMD severity and gravity. The mean
scores for CMD severity were 2 and 3.6 for genetically improved and local varieties,
respectively at 6 MAP. CMD gravity for improved varieties was below 21% for
genetically improved varieties and exceeded 85% for local varieties at the end
of trials. Area Under the Severity index Progress Curve (AUSiPC) and Area Under
Disease Progress Curve (AUDPC) estimates confirmed that improved varieties were
moderately infested comparatively to local varieties. Molecular analysis is
being conducted to determine the genetic variability and complexity of the
cassava mosaic virus strains involved.