Resistance to frost in Arabica coffee lines introgressed with Coffea racemosa Lour. genes

The aim of this study was to assess resistance to frost in Arabica coffees with introgression of Coffea racemosa. The field experiment (Londrina, Paraná, Brazil) was assessed after two consecutive frosts in June 2011. Eleven F2BC5 Arabica coffee lines with introgression of C. racemosa were assessed 52 months after planting. C. arabica cultivars IAPAR 59, Tupi IAC 1669-33, Catuaí Vermelho IAC 99 and Mundo Novo IAC 376-4 were used as sensitive controls. Foliar damages assessments were carried out 20 days after exposure to freezing temperatures. Foliar damages were scored using grades ranging from 1 to 5, where: grade 1 = no damage; and 5 grade = from 75.01 to 100.00% damaged leaf area. Levels of foliar damage (e.g. no damage – very severe damages) were classified according to the mean grades of the assessments. Severe leaf damage was observed in the controls, while nine lines showed moderate damage. H0107-32 line is the most resistant to frost, and is the only one which presented slight leaf damage