Differential Tolerance of Eleven Prunus Taxa to Root Zone Flooding

Abstract

Abstract Eleven taxa of own-rooted Prunus L. were subjected to incremental flooding for 7 weeks to assess relative tolerance to root zone flooding. Rates of net photosynthesis (Pn) decreased gradually as the flooding stress intensified. However, ‘Newport’ plum maintained higher Pn than any other taxa when root systems were completely submerged. Defoliation of flooded plants ranged from a low of 15% for ‘Newport’ plum to a high of 100% for ‘Canada Red’ chokecherry. Following a chilling period, survival of flooded plants ranged from a low of 0% for Carolina cherrylaurel to a high of 100% for ‘Newport’ plum and ‘F-12/1’ mazzard cherry. Of the 11 taxa evaluated, ‘F-12/1’ mazzard cherry and ‘Newport’ plum had the greatest tolerance to root zone flooding as indicated by high survival rates (100%) and low defoliation (≤27%). ‘Newport’ plum further demonstrated superior tolerance to flooding compared to other taxa as indicated by a greater capacity to maintain Pn during flooding and subsequent recovery. Carolina cherrylaurel, ‘Canada Red’ chokecherry, and ‘Peggy Clark’ Japanese apricot were relatively sensitive to flooding as indicated by low survival rates (≤50%) and considerable defoliation (≥82%). The remaining taxa, including Japanese bushcherry, Sargent, Yoshino, ‘Okame’, ‘Autumnalis’ and ‘Kwanzan’ cherries, were found to be intermediate in tolerance to flooding.