Validation studies on the detached pod test and leaf disc inoculation method for the assessment of cocoa resistance to Phytophthora infection

摘要: During the 5-year period of CFC/ICCO/IPGRI project "Cocoa Germplasm Utilization and Conservation: a Global Approach", series experiments was conducted using detached pod test - spray method (DPT-SM) leaf disc (LDT) to assess cocoa for resistance Phytophthora infections. Data obtained in at Cocoa Research Unit (CRU), The University West Indies, Trinidad Tobago, provide an opportunity validity DPT-SM LDT. Between 1998 2003, 742 accessions were assessed two trials rot (Ppr) DPT-SM. Significant variation observed reactions based on disease rating scale, showing that could effectively discriminate between various levels Ppr. A chi-square did not show any significant difference inoculation conducted. Furthermore, high correlation coefficient (r=0.80, P<0.001) trials, confirming results are repeatable. Among tested DPT-SM, 40 Ppr field conditions International Genebank, (ICG,T). among higher level susceptibility third year observations (63%) than first (15%) second (25%) years. This shows absolute reliance be placed single determining clonal result (r=0.66, with average years 1 3 each observations, which varied from 0.44 0.59. It is possible stronger association may exist cumulative data longer three overall confirms usefulness as effective assessing predicting reaction long term. differences 33 screened P. palmivora LDT different accessions. Correlations 0.49 0.77. poor (r=0.14) suggesting forms by might different. Since infects both leaf, organs complement other breeding infections cocoa. (Resume d'auteur)