Pathology and breeding for resistance to black pod in Cote d'Ivoire

Resistance to black pod is becoming an increasingly important selection criterion in Cote d'Ivoire. Early pathology research had shown presence of phytoalexins in Theobroma spp., but not in T. cacao. No interaction between Phytophthora palmivora isolates and clone resistance was identified. Seasonal variation in pod resistance was observed, which appeared to be related to variations in humidity and/or light intensity. Recent results have shown significant variation for field resistance in hybrid and clone trials. Heritability at single tree level was relatively high after many years of observation under uniform growing conditions. Genetic markers (QTL's) for field resistance were identified in one progeny, explaining 20 to 38 percent of total variation. Field level of attack appeared also to be affected by pod load and period of pod production (escape). Early screeining tests applied to 9 clones showed good correlation among leaf, twig and root inoculations and between these methods and general combining ability for fiel resistance. The use of leaf inoculations will be routinely introduced in the recurrent selection breeding programme initiated in the early 1990's.

Bibliographic Details

Main Authors:	82583 Kebé, I.B., 98199 N'Goran, J.A.K., 123208 Tahí, G.M., 103749 Paulin, D., 58027 Clément, D., 65489 Eskes, A.B., 36020 International Workshop on the Contribution of Disease Resistance to Cocoa Variety Improvement Salvador, BA (Brasil) 24-26 Nov 1996
Format:	biblioteca
Published:	Reading (RU) INGENIC 1999
Subjects:	THEOBROMA CACAO, PHYTOPHTHORA PALMIVORA, RESISTENCIA A LA ENFERMEDAD, FITOMEJORAMIENTO, VARIACION GENETICA, MARCADORES GENETICOS, POLITICA DE DESARROLLO, COTE D'IVOIRE,
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