Contrasting responses to flooding in two F1 progenies of Populus deltoides W.Bartram ex. Marshall.

RODRÍGUEZ MARÍA EMILIA; MONTEVERDE, SILVANA; MOZO IRINA; CAPPA EDUARDO; CORTIZO, SILVIA; LUQUEZ VIRGINIA M.C.

BUENOS AIRES

Simposio; VII IUFRO International Polar Symposium; 2018

One of the biggest impacts of climate change worldwidewill be alteration of precipitation patterns. Climate change scenarios indicatethat there will be an increase in the occurrence of extreme rainfall events incertain areas, causing more frequent flooding episodes. Even when these stressevents do not cause plant death, some forest species like poplars canexperience a reduction in growth and productivity. For this reason, it isnecessary to increase the knowledge of the adaptive mechanism of poplar toflooding to obtain clones with improved performance when exposed to waterexcess. Two flooding trials were performed with F1 progenies obtained from twodifferent crosses of Populus deltoides parents with varying degree ofsusceptibility to flooding. The first family involved a cross of clones ʽAustraliano106/60̕ x ʽStoneville 67΄; the genotypes analyzed were both parents and 30 individualsfrom the F1. The second family was a cross of clones ʽNandi INTA x ʽCarabelasINTA΄, and the experiment included the parents and 29 genotypes of the F1. Cuttingsof all genotypes were planted in pots in a greenhouse, and the floodingtreatment started when the plants were two months old.  Both experiments included two treatments:plants watered to field capacity (C), and plants flooded 10 cm above soil level(F) for 35 days; with 6 replicates per genotype and treatment. Morphologicaland physiological responses to flooding of the progenies were evaluated toidentify traits useful as a screening tool for flooding tolerant clones. Floodingtolerance was determined as the percentage of above ground dry biomass of the Ftreatment compared to the C treatment. Both F1 showed variability in floodingtolerance. For the ʽAustraliano 106/60̕ x ʽStoneville 67΄ family, most clonesof the F1 showed a higher flooding tolerance than any of the parents. In theother family, most F1 genotypes were more tolerant than the mother ʽNandi INTA΄and less tolerant than the father ʽCarabelas INTA΄. These results indicates that there is a considerablevariability in flooding tolerance in P. deltoides. This variability can be tapped bybreeding programs to obtain genotypes with increased flooding tolerance andthus reducing the negative impact of climate change in poplar plantations.