Morphological Character Variations in Lasiodiplodia Species: Pathogen of Inflorescence Dieback in Cashew Growing Ecologies of Nigeria
Nine isolates of Lasiodiplodia theobromae were collected from cashew inflorescences showing typical symptoms of dieback disease in nine different farms belonging to various cashew growing ecologies of Nigeria. The result revealed that most of the Lasiodiplodia species isolates exhibited significant differences in morphology, colour and spore dimensions. The colony growth rate of Lasiodiplodia species range from 11.95 mm to 14.17 mm, colony texture and colour of the isolates in the obverse were fluffy dark mouse grey, fluffy mouse grey, fluffy olivaceous grey or fluffy groh grey while the reverse colour of the isolates was either greyish blue or sky grey. Sporulation was observed at varied degrees in all the Lasiodiplodia species isolates except in isolates from Oro and Ejule and likewise is the numbers of pycnidia produced varied in all the isolates across growing ecologies. Significant variations were observed in the characters and morphology of the Lasiodiplodia species isolates causing inflorescence dieback of cashew in Nigeria. Conidia of all isolates are septated with single septa but the septa sizes varies and conidia sizes also differ. Eigenvalues and variance proportion consistently decreased among selected characters and the proportional contribution of each character to the total variance also varied in dimension and quantity. Four clusters significantly evolved in the dendogram with 2, 2, 4 and 1 isolates within each cluster.
Dele Omoyele Adeniyi
Department of Plant Biology, University of Ilorin, P.M.B. 1515 Ilorin, Nigeria and Plant Pathology Section, Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Nigeria.
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