Progeny performance and pathogen attack relative to elevation in a neotropical tree

Abstract

Climate and resource availability at the parent tree location are known to explain progeny characteristics; however, few studies have examined the role of resistance or tolerance to pathogens, even though climate is a main driver of pathogen abundance. We hypothesize that climate at the parent tree location has a relatively greater influence on progeny resistance or tolerance to pathogens than other progeny characteristics, such as seed mass or seedling growth. As a study species we used the vulnerable Neotropical tree Kageneckia lanceolata known to be susceptible to damping-off diseases. We collected seeds from 60 trees along the species entire elevational gradient in central Argentina as a surrogate for climatic gradient and selected an ample array of parent tree sizes and rockiness under the crown as surrogate of tree access to resources. Seedling survival in a common nursery significantly increased with elevation of the parent tree from 40 to 80 % (P < 0.001), with damping-off being the only identified cause of mortality. We also found a non-significant trend suggesting that proportional growth during the cold semester increased with elevation (P = 0.083). Seed mass, germination, and growth of seedlings were not significantly influenced by elevation (P > 0.05). Parent tree size and rockiness were not related to any of the measured progeny characteristics. We conclude that the pathogenic environment around parental plants might have a great influence on progeny resistance or tolerance to pathogens and suggest that incorporating the pathogen dimension into future progeny studies may yield important findings.