Evaluation of coffee berry disease resistance (Colletotrichum kahawae) in F2 populations derived from Arabica coffee varieties Rume Sudan and SL 28

Abstract

Coffee supports livelihoods of approximately 125 million families worldwide and over 700,000 households in Kenya. The epidemics of Coffee berry disease (CBD), caused by Colletotrichum kahawae, destroy up to 80% of the developing berries on susceptible varieties. The control of the disease using chemicals accounts for 30 to 40% of the production cost and contributes to environment pollution, hence the use of resistant varieties. Resistance to CBD is conferred by three genes; R, T that are dominant and k which is recessive, from coffee varieties Rume Sudan (RS), Hibrido de Timor (HDT) and K7 respectively. Although the T gene has been mapped, there is need for genetic mapping of the other genes to improve selection efficiency. The objective of this study was to evaluate F2 populations of RS x SL28 for their suitability to genetic mapping of the R gene in RS. Resistance to CBD was evaluated by hypocotyl inoculation on their F3 progenies. The data was subjected to Analysis of Variance (ANOVA) and Chi Square (χ²) test. The ANOVA result showed significant differences (P≤0.05) between the genotypes to CBD resistance. The phenotypic ratio of resistance to susceptible plants fitted the 3:1 monohybrid inheritance ratio for a dominant gene using the χ² test (χ² = 1.0565 and P=0.30207, P≤0.05), hence confirming the suitability of the F2 populations for the identification of the DNA marker for R gene in RS.

Quantitative trait loci (QTL) mapping of resistance to coffee berry disease (Colletotrichum kahawae Waller Bridge) in Coffea arabica L. variety Rume Sudan

“…The analysis of population structure reduces type I error during association mapping (Camacho et al, 2019). The mapping population was confirmed as a suitable population for genetic mapping of a dominant gene-based and Chi-Square test based on 3:1 Mendelian ratio of segregation (Gimase et al, 2019).…”

“…The phenotypic variation among the 106 F 2 genotypes with their parents and inheritance segregation ratio of the gene for resistance to CBD was reported in an earlier publication (Gimase et al, 2019). Evaluation of population structure on the relatedness of the 106 F 2 genotypes and their parents using the PCA revealed that a total of 20 F 2 genotypes were weakly related with the rest of the genotypes and were therefore excluded from QTL analysis.…”

“…After filtering, 1170 SNP markers were anchored to the 11 coffee chromosomes that were utilized for further analysis in the study. The phenotypic data analysis is described in a recent study by Gimase et al (2019). The PCA clustering analysis of 108 genotypes revealed three main clusters: A, B and C (Figure 1).…”

Integrated Disease Management for the Sustainable Production of Colombian Coffee

“…Efforts to develop resistance to other diseases, such as coffee berry disease (CBD), have been noteworthy. The selection of progenies for CBD resistance involves utilizing molecular markers associated with genes from the Rume Sudan accession (R gene) and the Timor Hybrid (T gene), which are already incorporated into commercial varieties in Kenya and Colombia [48,49]. Field trials have also been conducted to assess resistance to ceratocystis canker (Ceratocystis fimbriata and C. colombiana) using a Bourbon variety accession [50].…”

Detached berries response to coffee berry disease (Colletotrichum kahawae) of F1 hybrid genotypes developed from Ethiopian accessions of Arabica coffee

“…CBD was first documented in Tanzania in 1964 and has subsequently spread to all coffee-producing regions. Following its initial discovery in Ethiopia, coffee berry disease rapidly propagated throughout major coffee-growing areas, excluding lower elevation regions (Gimase et al, 2019). The majority of Arabica coffee-producing areas are situated at high altitudes, characterized by high humidity and low temperatures.…”