TITLE:
Morphological and Biometric Diversity of Colletotrichum capsici Isolates, Causal Agent of Cowpea Brown Blotch Disease (Vigna unguiculata (L.) Walp) in the Sudano-Sahelian Zone of Cameroon
AUTHORS:
Fankou Dougoua Merline Yoyo, Sobda Gonne, Philippe Kosma, Teguefouet Feujio Pierre, Iyale Liliane, Zaiya Zazou Arlette, Metsena Pierre, Melie Feyem Marie Noel, Amedep David, Djeoufo Yvonne, Gnapou Dieudonné, Erik W. Ohlson, Michael P. Timko
KEYWORDS:
Cowpea, Isolates, Colletotrichum capsici, Diversity, Sudano-Sahelian Zone
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.12 No.11,
November
17,
2022
ABSTRACT: Cowpea [Vigna unguiculata (L.)
Walp] is an important legume in the midst of about 170 species of its genus
because it is an important source of protein and other essential nutrients for
humans and animals. Its production faces many constraints such as the cowpea
brown blotch disease caused by Colletotrichum capsici which
contributes in wet conditions of the field to losses ranging from 42% to 100%.
This study was conducted to identify Colletotrichum capsici isolates
responsible for cowpea brown blotch disease and to determine their diversity in
the Sudano-Sahelian zone of Cameroon. Identification and isolation were made
from cowpea organ samples on the Potato Dextrose Agar (PDA) medium and,
morphological and biometric characteristics such as: the colony color, the
mycelium shape, the abundance of acervules, the presence or absence of
saltations, the mycelial growth rate, the conidia length and width were used to
assess the diversity. The results obtained indicate that 55 Colletotrichum
capsici isolates have been identified in the Sudano-Sahelian zone of
Cameroon. Statistical analysis showed that there is a significant difference between
isolates. Isolates showed multiple colony colours and were brown coloured as
presented by 36.36% of isolates, compact mycelium is found in 56.36% of
isolates, 56.36% of isolates have abundant acervulis, and saltations were
absent in 45.45% of C. capsici isolates. The mycelial growth rate is
between 6.69 mm/d and 12.33 mm/d. The principal component analysis (PCA) made indicated that there are
differences between the observed and measured characteristics. The Hierarchical
Ascending Classification (HAC) was done and 10 morphotypes of C. capsici in the Sudano-Sahelian zone were identified.