The Physical, mineral and hormonal changes in developing carabao mango fruit under different irrigation treatments / by Bonifacio E. Lapade

Thesis (D.P. - - Horticulture) University of the Philippines, College, Laguna.

Includes bibliographical references.

Bonifacio E. Lapade, University of the Philippines at Los Baños July 1977. The physical, mineral and hormonal changes in developing “Carabao” mango fruit under different irrigation treatments. Major Professor: Dr. Robert E. Coronel.

The effects of irrigation on physical changes, mineral nutrient and growth regulator contents of ‘Carabao’ mango fruits at different stages of development were determined. Four irrigation treatments were made: 0, 150, 300 and 600 gallons of water per tree. Trees were irrigated at 10 days after budbreak and at weekly intervals thereafter until 48 days after full bloom.

Irrigation significantly increased the number of fruits per panicle. At harvest, trees receiving 0 and 150 gal of water had an average of 0.4 fruit while those irrigated with 300 and 600 gal of water produced 1.0 and 1.4 fruits per panicle, respectively.

The growth of Carabao mango fruits followed a single sigmoid curve, irrespective of the irrigation treatments applied.

The application of 150, 300 and 600 gal of water per tree increased the fresh weight of the individual fruit by 17.1, 22.8, and 13.1 and dry matter contents by 17.1, 19.8, and 4.5%, respectively.

The increases in fresh weight, dry matter, length, thickness and width of fruits were consistently of greater magnitude in trees irrigated with 150 and 300 gal of water and relatively lower in 600 gal treated trees. The differences were attributed to the differences in the number of fruits obtained in these treatments.

The concentrations of N, P, K, and Mg generally decrease with increasing stages of fruit development. The reductions were attributed to the dilution effect as a result of growth with the uptake of these elements. Potassium, N and Ca were needed in large amounts by developing fruits. The need for Mg and P was comparatively small.

Irrigation significantly increased N, K, Ca, Fe, Mn and Zn. but did not significantly affect Mg and P concentrations of fruits. In the leaves, only Ca and Zn were significantly affected by irrigation treatment. The trees irrigated with 300 gal of water consistently showed higher amount of the nutrients elements. The differences in the concentrations of these elements at varying moisture conditions in the soil were explained by the number of fruits present in the tree, the relative availability of the elements at a given level of soil moisture and/or the combinations of both.

The total N, P, and K, removed by a mango tree irrigated with 300 gal of water were about 320, 150, and 3075 g, respectively.

Thus the recommended fertilizer rate of 2.5 kg per tree of 14-14-14 was sufficient for N, and P, but deficient in K.

Irrigation increased the level of nixon- and gibberellin-like substances. The greatest increase was obtained in 300 gal treatment followed by 150 and 600 gal of water treated trees in that order.

Irrigation did not significantly affect the pH, % TSS and properties of fruits.

Submitted to the University Library April 29, 1988 T-1133