Abstract:

In order to further improve the introduction and cultivation of Rhododendron, and select suitable varieties for planting in Sichuan basin, growth index of the whole plant (crown width, plant height, ground diameter), branches (longest branch length, single branch thickness, the number of leaf at the longest branch), leaf (leaf length, leaf width, leaf thickness), and summer branches length of 14 introduced new varieties of Rhododendron were evaluated in this comparative study. The results showed that the adaptive growth performances of 14 varieties were different, the crown width and plant height of ‘Prince Lavender’ increased the most, which were 8.40% and 27.79% respectively; the ground diameter of ‘Strawberry Sundae’ increased the most by 20.04%; the longest branch length of ‘Atlas’ increased the most by 11.13%; the single branch thickness, leaf length and leaf width of ‘Mrs. Fujiichi’ increased the most, which were 15.48%, 17.66% and 18.48% respectively; the number of leaf at the longest branch, leaf thickness and summer branches of ‘Purple Rainbow’ increased the most, which were 43.36%、5.98% and 5.98 cm respectively. Four factors were obtained from principal component analysis, and the cumulative variance contribution rate reached 84.560%, the comprehensive scores of ‘Strawberry Sundae’ was relatively high. Collectively, varieties with scores of grade II and above are more suitable for summer growth under sparse forest (semi shading) conditions in Sichuan basin, such as ‘Strawberry Sundae’, ‘Princess Pearl’, ‘Sweetheart’, ‘Atlas’, ‘Mrs. Fujiichi’, and ‘Purple Rainbow’.

Key words: Rhododendron spp., summer, growth, principal component analysis, heat-resisting