Effect of harvest time and fruit size on seed germination and seedlings growth of sour orange and Mexican lime under in vitro conditions

Abstract

The aim of this research was to determine the best time to harvest the fruits for seed production which would ultimately lead to the production of citrus rootstocks of optimum quality. The sour orange and Mexican lime fruits were harvested on 7 and 5 occasions, respectively. The very first fruits were harvested 80 days after flowering and subsequent harvests were gathered every 30 days. An in vitro experiment was carried out in a completely randomized design, with four replications and 20 seeds in each replication. Based on fruit growth curve the time of fruit harvest affected seed germination (percentage and rate) and seedling growth (stem and root length, fresh and dry weight of stems, roots and leaves).  The results showed that the best time to harvest the fruits of sour orange and Mexican lime was 230 and 170 days after flowering, respectively, which led to maximum seed germination (Mexican lime 100% and sour orange 85%) and seedling growth. The highest root, stem and leaf fresh and dry weight was also obtained at 230 and 170 days after flowering in sour orange and Mexican lime respectively.