Effect of Some Treatments on Seeds Number, Yield and Fruit Quality of Acidless Orange Tree "Succarri" (Citrus sinensis L.)

Abstract

Seedless fruits are preferable for fresh consumption. The acidless orange cultivar "Succarri" contains a lot of seeds, reaching over 20 seeds/ fruit under normal conditions. The present investigation was conducted to assess the impact of three recommended treatments for reducing citrus seed formation, including Cover (net covering), InsRep (natural insect repellent based on hot pepper) and SulfurGA (25 mg L−1 CuSO4.5H2O + 50 mg L−1 GA3), as well as their combinations as a trial to reduce seeds in "Succarri" orange fruits. Foliar applications were conducted three times at 25, 60, and 90% of opened flowers during the two successive growing seasons of 2021 and 2022. The results revealed that using SulfurGA alone or combined with InsRep resulted in the highest fruit weight, fruit number, and overall yield per tree throughout both seasons. The highest SSC were recorded with SulferGA and InsRep separately as well as their combination in 2021 and with SulferGA alone and SulferGA+ InsRep in 2022. The application of SulfurGA increased the percentage of incomplete seeds in both seasons and decreased the average number of seeds/ fruit from 20 to 18 in the first season and from 23 to 20 in the second one. The lowest average seed number in both seasons (around 16 seeds/ fruit) was recorded with Cover. Total and incomplete seed numbers per fruit are correlated to the viability percentage of pollen grains in treated flowers. The obtained results suggested a hypothesis that seed formation in "Succarri" oranges depends on self-pollination more than cross-pollination.