An evaluation of two seedling phenotyping protocols to assess pH adaptability in deciduous Azalea (Rhododendron sect. Pentanthera G. Don)

Deciduous azaleas are an important element of residential and commercial landscapes in the United States after substantial trait improvements to increase their market appeal. Despite progress in breeding for ornamental characteristics and cold hardiness, intolerance to elevated pH and calcareous soils continues to limit their use in managed landscapes. Therefore, we assessed the utility of in vitro and greenhouse phenotyping approaches to evaluate and select for improved soil pH tolerance to increase the efficiency of breeding for this important trait. The research presented offers an example for implementing image-based phenotyping to expedite cultivar development in woody ornamental crops.