ESTIMATION OF THE FOLIAR AREA IN APPLE

Abstract

With the idea of developing an equation to estímate apple leaf area for "Golden Delicious" cultivated in Bachiniva, Chih., four hundred leaves were taken during the summer of 1990, from the middle of the tree canopy and from of one year shoots of adult
trees of the Golden Delicious cv under two management conditions: irrigation and no irrigation. The rootstock used in irrigation orchard was MM.106, 15 years old, soil fertilization was 90-50-50 before flowering, with a plantation density of 5x3 m. The rootstock used in no irrigation orchard was seedling, 18 years old, without fertilization, and a plantation density of 6x7 m. Leaf area was detennined with a leaf area integrator (Li-Cor Model LI-3000A) and compared with three indirect methods: 1) length x width, 2) the area of an ellipse, and 3) half of ellipse area plus the area of an isosceles triangle. Results showed that the equations: 1) Y= 0.69 + 1.08X (where Y represents leaf area estimates in cm² and X the ecuation of ellipse area = 3.1416/4{length * width} ); and 2) Y= 0.53 + 0.89x (where Y estimates leaf area in cm², X the ecuation of half ellipse area plus an isosceles triangle area based in half of the leaf length x width = (3.1416/4{length x wide} )/2 + (1/2xa)/2) estimated significantly the apple leaf area with 95% of confidence, determination coefficient of 94% and standar error estimation of 0.14 and 0.12 cm² respectively. The validation of these ecuations showed than they reached a 95% confidence level.