Effect of PGRs combination on pre-harvest fruit drop of Khasi mandarin (Citrus reticulata Blanco.)

The synthetic auxin like 2, 4-D, 2, 4, 5-T and NAA were investigated on ten (10) years old tree to study the effect of different combinations of PGR on pre-harvest fruit drop at Bodak village under East Siang district of Arunachal Pradesh, India during the year 2014–2015. Result showed maximum fruit retention in T6 Urea 1% + 2, 4-@ 15ppm (45.4%) followed by T5 NAA@5ppm + 2, 4-D@10ppm (44.3%) resulting significantly increased the total number of fruits in (T6) (244.3 fruits/tree) followed by T5 (241.6 fruits/tree) as compared to control (17.3% fruit retention and 181 fruits/tree) Hence, the combination of recommended dose of fertilizer i.e. 400: 400: 900g NPK/plant/year along with Urea 1% + 2, 4-@ 15ppm foliar spraying thrice during April, July and September can be used to control the fruit drop in Khasi mandarin.