EFFECT OF CPPU TREATMENT ON FERN NUMBER, BUD NUMBER, AND PHOTOSYNTHETIC RATE OF ASPARAGUS

The effects of N₁-(2-chloro-4-pyridyl)-N₃-phenylurea (CPPU) application to foliage and root on fern numbers, bud numbers, cladophyll morphology and photosynthetic rates were observed. Fern numbers and total buds showed a maximum response to CPPU as a foliar spray at 5 ppm. Combined root and foliar applied CPPU severely inhibited the production of buds. CPPU as a foliar spray at 5 and 10 ppm was effective in producing longer and thicker cladodes, features often associated with increased photosynthetic rates and yields. However, photosynthetic rates were unaffected by CPPU foliar spray. Cultivar 'Jersey Giant' had a higher photosynthetic rate than 'UC 157'.