Modifications in floral morphology of Coffea spp. genotypes at two distinct elevations

Floral traits are influenced by elevation in various species, but no information is available for the Coffea canephora and C. arabica. It was hypothesized that: 1) number of stamens and petals can vary depending on the species and genotype within the same species; 2) variations in the morphological traits occur in response to the difference in elevation, 3) greater variability in flower morphology among C. canephora genotypes is expressed at high- than at low-elevation, due to environmental pressure, and 4) the changes in floral morphology due to alterations in elevation are more pronounced in C. canephora than in C. arabica. This study aimed to investigate the G × E interaction for morphological traits of coffee flowers and, based in genetic parameters estimation, explore the potential use of these traits in breeding programs. Experiment comprised of coffee plantations under full sun of both species at two elevations. The number of petals and stamens varied between five and six in C. canephora. At two elevations, Beira Rio 8 (C. canephora) genotype stood out for presenting the highest averages for all size traits related to corolla, and stigmatic lobes. The variability in floral morphology among C. canephora genotypes was not greater at high- than at low- elevation. Overall, flower size of all studied C. canephora and C. arabica genotypes was larger at low- than at high-elevation, but the stigmatic lobes length, the ratio between stigmatic lobe length and style length, and partially the ratio between anther length and stamen length were greater at high-elevation. C. arabica flowers were smaller and mostly irresponsive to elevation, in contrast with C. canephora flowers. There was a significant genotype by environment interaction for seven out of the nine traits, with a predominance of complex-type interactions. Conducting studies on morphological traits of flowers at a greater number of environments with distinct elevations can provide better insights into the potential use of these traits in studies of adaptability and stability of Coffea spp. genotypes to different environmental conditions, contributing to genetic improvement efforts to achieve resilience of coffee cultivation in the scenarios of climate change.