Coffee resistance to brown eye spot: genetic variability and influence of plant nutrition on the expression of resistance

• Grant number: 09/08073-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2009
• End date: April 30, 2012
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Oliveiro Guerreiro Filho
• Grantee: Márcia Santos Silva
• Host Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil

Abstract

Brown eye spot caused by Cercospora coffeicola (Berk & Cooke) is an important coffee nursery disease, recently associated to major losses in all Brazilian regions. Occurrence and severity of disease are affected by nutritional deficiencies. Resistant cultivars would be a desirable control alternative although so far source of resistance are unknown among Coffea species. Studies will be addressed by five experiments. In the first, the methodology for evaluation of the disease will be studied regarding how this is affected by the age of plants and concentration of conidia in the suspension. In the second experiment the level of resistance of progenies IAC 5026 and IAC 5028 will be evaluated. Cultivars Tupi IAC 1669-33 and Bourbon Amarelo IAC J19 will be used respectively as resistant and susceptible controls. The influence of Nitrogen and Potassium levels on the resistance response will be evaluated in a third experiment using clones of F1 hybrids H8105-7 (Resistants) and cultivars Tupi IAC 1669-33 (R) and Bourbon Amarelo IAC J19 (S). Expression of defense related genes or genes involved on transport and regulation mechanisms of N and K will be evaluated in a fourth experiment. Cultivars Tupi IAC 1669-33 (R) and Bourbon Amarelo IAC J19 (S) will be submitted to the same levels of N and K of previous assay. In the fifth experiment the possible selection gain over breeding generations will be estimated, once F6 plants exhibit have field resistance to the fungus. Genetic analysis of variables related to the development of plants will be performed. In all investigations the occurrence and severity of disease will be recorded as an indicative of the plant resistance level.