A comparative study of early fruit agscission on ‘Marsh’ grapefruit and ‘Valencia’ orange under Cuban tropical conditions. I. Physical characterization

Abstract

A comparison between early fruit abscission on ‘Marsh’ grapefruit and ‘Valencia’ orange was carried out. Low levels at early fruit development stages and further increase of fruit detachment force throughout exponential fruit growth period (Phase II) were found for both orange and grapefruit. At the same time, actual fruitlet detachment zone shifted from proximal (A) to distal (C) abscission layers. Fruit abscission stopped toward the end of logarithmic growth of phase I on }’Valencia’ orange, whereas it delayed 30-50 days n ‘Marsh’ grapefruit. On the other hand, continuous fruitlet abscission periods, instead of postblooming and june drop waves, were identified ‘Valencia’ fruitlet drop stopped some 40-50 days after anthesis (DAA); in contrast, that of ‘Marsh’ lasted as late as 90 or 100 DAA. So that latest fruitlet abscission reached phase II and involved half-maximum size fruits.