Physiological aspects, growth and yield of Coffea spp. in areas of high altitude

Abstract

Low temperature and water deficit are the major climatic limitations for the coffee plant, affecting metabolic performance, development and yield. This work aims at evaluating the physiological responses of Coffea spp. genotypes grown in high-altitude (734 m) areas under field conditions, using 3-to-4-year-old plants of C. arabica cv. Catuca Vermelho (785/15) and C. canephora cv. Encapa 8111 Clone 02 (02V). Predawn leaf potential water, net photosynthesis, stomatal conductance, internal-to-external CO 2 concentration ratio, and chlorophyll a fluorescence (JIP Test ) values were assessed in March (adequate temperature and water availability conditions), July (suboptimal temperature) and October (low water availability). The growth of orthotropic and plagiotropic branches and the number of nodes were monitored monthly for 13 months, whereas two years yield was evaluated. Low temperatures (July) affected photosynthesis of both genotypes, although 785/15 showed smaller after-effects by October and unaltered values of almost all fluorescence parameters throughout the year (reflecting a high functional stability), and a higher number of nodes with a potential positive impact on yield. The 02V plants also kept relevant photochemical functioning, maintaining the values of several JIP Test parameters, a branch growth higher than 785/15, and a similar yield to that found for 02V in some lowaltitude areas. Therefore, C. canephora was able to cope with moderate low temperature and water deficit constraints that prevail in areas of higher altitudes for part of the year, while maintaining yield performance. Therefore, this genotype shows considerable potential to be cultivated at higher altitudes than what is traditionally considered adequate for C. canephora.