EFFECT OF A FORCHLORFENURON DIP ON KIWIFRUIT FRUIT SIZE

All the fruit from kiwifruit vines (Actinidia deliciosa (A.Chev.) C.F. Liang et A.R. Ferguson cv. Hayward) were dipped in 10 mg/litre solutions of forchlorfenuron (N-(2-chloro-4-pyridyl)-N-phenylurea) 35 and 36 days after full bloom at two sites in the 1989/90 season and 22 days after full bloom at one site in 1990/91. Growth curves showed that treated fruit grew 30-60% faster than untreated fruit, both during the rapid cell division and expansion phase (first 53-74 days after full bloom), and during the subsequent slower cell expansion phase through to harvest. The mean harvest weight of export quality fruit from forchlorfenuron treated vines was in by 27-46% (average weight for three sites 143 g) compared to untreated fruit (107 g). Forchlorfenuron treatments did not influence overall rejection rates. Forchlorfenuron treatments appeared to increase some fruit shape defects but that was compensated by a reduction in pollination and blemish defects. At harvest, forchlorfenuron treated fruit had lower total soluble solids and flesh firmness than untreated fruit.