Classification of Zoysiagrass Genotypes on Rooting Capacity and Associated Performance during Drought

When characterizing rooting capacity for improving drought resistance of turfgrass, the most relevant information can be difficult to extract when a larger number of genotypes and root variables are included. The objectives of the study were to 1) classify root capacity of zoysiagrass (Zoysia spp.) genotypes and cultivars using a multivariate analysis – principle component analysis (PCA) and compare the results with the analysis of variance (ANOVA); and 2) to relate the results with the turf performance in a field dry down experiment. The greenhouse study included seventeen zoysiagrasses grown in clear acrylic tubes. Root morphological traits and dry weight at different horizons were evaluated. The field dry down experiment lasted 17 and 20 days in two trials, respectively. Total turf performance index (TTPI) was used to rank the zoysiagrass genotypes and cultivars based on their turfgrass quality ratings. Analysis of the root study using both ANOVA and PCA produced similar results. Genotypes that had higher root length density (RLD) and root dry weight (RDW) at 30-120 cm and maximum root depth (MRD), lower surface horizon/total horizon in RL and RDW (A/Total) were better performers in the field dry down such as ‘Palisades’, ‘Emerald’, ‘UF 182’ and ‘JaMur’. Use of PCA reduced the dimensions of the root variables and provided separation of the genotypes similar to the results from the field dry down study. The results suggested that using acrylic tubes in the greenhouse was representative of drought responses in the field where variation in drought avoidance mechanisms is found.