Morphological traits related to flooding tolerance during the early growth of willows

MOZO I; MONTEOLIVA S; CERRILLO T; LUQUEZ V

Roma

Congreso; 8TH INTERNATIONAL POPLAR SYMPOSIUM, IPC 2021; 2021

IPC

Willow commercial genotypes are usually propagated as unrooted cuttings. During the establishment phase, the cuttings are developing their root system and leaf area, and are more vulnerable to the occurrence of stresses like flooding, leading to failure of new plantations. In consequence, it is relevant to identify traits correlating to flooding tolerance during the early growth of willows. We evaluated the flooding tolerance of plants obtained from cuttings of 29 willow genotypes from the breeding program of INTA Delta (Argentina), comprising different species: Salix matsudana, S. alba, S.nigra, S. jessoensis , S. amygdaloides, S. humboldtiana, S.viminalis, S. babylonica and the interspecific hybrids S.matsudana x S.alba, S. fragilis x S. alba and S. matsudana x S. nigra. Two-months old plants growing in pots in a greenhouse underwent two treatments: watered to field capacity (control) and flooded (80% of the stem covered by still water) for 43 days. At the end of the stress episode, growth and morphological traits were measured: height, collar diameter, total dry biomass, root-toshoot ratio, total leaf area and wood density. A flooding tolerance index for each genotype was estimated as the percent ratio between flooded and control total biomass. There was ample variation in flooding tolerance, with the index ranging from 39% to 112 %. Most clones had a reduced biomass accumulation under flooding conditions and only 4 genotypes had similar or higher biomass than control plants. The Pearson correlation coefficient was estimated between the flooding tolerance index and the different variables measured. Several traits had a positive and significant correlation with flooding tolerance: height (r=0.69 p