Virulence Test of Some Phytophthora Megakarya Isolates on Cocoa (Theobroma Cacao L.) Hybrid Pods
Year: 2017
Type: article
Abstract: Phytophthora megakarya is an Oomycete which has a negative impact on Cameroon cocoa production.An assessment of the level of virulence of different isolates of P. megakarya in mono or coinfection was performed on some hybrids of cocoa (Theobroma cacao L.) obtained from reciprocal crosses.The isolates tested on eight cocoa hybrids obtained by hand pollinisation were Bakoa, Le4 and Lebdi.Contents of soluble amino acids, sugars, polyphenols and proline were determined using standard methods in mono or coinfected cocoa pods.This study revealed that, the development of the necrotic area in the cortex of cocoa pods was genotype-dependent and isolate-dependent after infection.For this reason, the classification in terms of virulence of isolates was the following: Lebdi<Le4<Bakoa.However, SNK 413 x T 79/501 and T 79/501 × SNK 413 hybrids were the most tolerant while UPA 134 x ICS 40 and T 79/467 × SNK 13 hybrids proved to be the most sensitive to threeP.megakarya isolates.Bakoa + Le4 combination was the most aggressive among the other combinations.Groupings of samples were observed using principal component analysis (PCA) and hierarchical cluster analysis.Significant and negative correlations were found between necrosis and three biochemical metabolites (total polyphenols, soluble sugars, Proline andsolubleamino acids) in cocoa hybrids suggesting that these metabolites could be considered as markers of resistance in T. cacao/P.megakarya interactions.
Institution: Université de Yaoundé I
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: bronze
OpenAlex ID: W2588995349