The researchers wanted to see if spraying zinc sulfate on Kinnow mandarin trees before harvest could improve fruit quality and reduce fruit drop. They tested different levels of zinc sulfate and found that the 0.6% concentration was the most effective. This treatment led to fewer fruits falling off before harvest, increased fruit yield, and improved fruit quality. The mandarins treated with 0.6% zinc sulfate were heavier, juicier, sweeter, and had more antioxidants and phenolic compounds compared to untreated trees. Overall, spraying 0.6% zinc sulfate on Kinnow mandarin trees four months before harvest can help produce better quality fruits with less pre-harvest fruit drop.