The Morphology Associated with Harvesting Stages of Siam Red Ruby Pumelo (Citrus grandis)

Abstract

This study aims to evaluate fruit morphological characteristics and potential production of ‘Siam Red Ruby’ pumelo from Pak
Panang district, Nakhon Si Thammarat Province compared between normal and senescence fruit peel. A three-year-old tree was selected to evaluate fruit morphological characteristics and a harvesting date or time at 90, 120, 150, 180, and 210 days after fruit Set (dAfS). The result showed anatomical association to the senescence of ‘Siam Red Ruby’ pummelo using the peel of normal and senescence zones using compound microscopy. The ‘Siam Red Ruby’ pummelo was shown a green color inside a peel 90 days after fruit setting and in a peel showed a trichome or hair covering all the fruit (100%) then decreased during fruit development until 210
days after fruit setting showed the hair cover 20%in all fruits compared with others stage. during the maturity stage, the pulp was yellow-colored from 90 to 120 days after the fruit set. from 150 days after the fruit set, the pulp turned red gradually. In addition, the structure of the peel was changed during senescence. The first day of the peel or normal zone showed high firmness and peel green color. In the senescence zone, the peel changed to a yellow color. In addition, Titratable Acidity (TA) decreased from 90 to 210 days after fruit setting and related with Total Soluble Solid (TSS) increased from mature fruit (90 days after fruit setting) to ripening fruit (210 days after fruit setting). In reflective sheet treatment, clouds induce the red color in the pulp of ‘Siam Red Ruby’ pumelo.