Effect of prohexadione calcium on vegetative growth, yield and scab development on ‘Sinap Orlovskii’ apple trees

There are many apple orchards in the Russian Federation where trees were trained with volumetric canopies; vigor of these canopies must be suppressed. Prohexadione calcium (calcium 3-hydroxy-5-oxo-4-propionyl-cyclohex-3-enecarboxylate) was developed to inhibit gibberellins biosynthesis reduce vegetative growth. The study done commercial orchard “Planeta sadov” LLC Michurinck district Tambov Region (53°02’11.9 “N 40°29’29.9 “E). This research aimed evaluate influence prohexadione on length one-year shoot growth, yield, and scab development vigorous cultivar ‘Sinap Orlovskii,’ planted 6 x 4 m (418 tr. ha-1). After 1.25 + g ha-1 double treatment, shoots 1.96 (2019) 1.60 (2020) times less than Control 1 (without application hand pruning) 2,00 pruning treatment. inhibited tree height reduced average growth rate by 10.7% 17.0% (2020). Growth retardant treatments stimulated significant yield increases improved value fruits. enhance protection under treatments. increased alternate bearing index.