BIENNIAL BEARING AND PROTEIN-CONTENT OF APPLES AS INFLUENCED BY HIGH-CONCENTRATIONS OF FOLIAR NITROGEN AND SULFUR

Effect of different foliar applications of urea and ammonium sulfate a t high concentrations after 8, 9, and 10 weeks of full bloom were stud ied in ''on'' selected 'Golden Delicious' and 'Redspur Delicious' alte rnate bearing apple trees. Leaf samples were taken one week before and after sprays for protein analysis with Near Infrared Reflectance (NIR ). Percentage of flowering and fruit length to diameter ratios (L/D) w ere measured in both cultivars. Number of fruits only in 'Redspur Deli cious' were recorded during ''on'' and ''off'' years. Spray of nitroge n (N) and sulfur (S) increased leaf protein content up to a certain le vel in all treatments. Leaf protein content in leaves of all applicati on dates were significantly higher than non-sprayed in both cultivars. Foliar applications at different periods reduced flower percentage. F oliar sprays increased number of fruits in 'Redspur Delicious' in the ''on'' year, but did not affect different treatments during the ''off' ' year. The sprays in 8, 9, and 10 weeks of full bloom intensified alt ernate bearing in the following ''off'' year.