While heat and humidity are known for causing oxidative macromolecular cell damage related seed deterioration during storage under subtropical conditions, information on effect of UV radiation that is also known to cause bio-molecular as well as direct hit damage in plants is largely lacking. A study involving measurements of UV irradiance in seed storage and also over open fields during seed maturation reveals an inverse correlation between genetically conferred (varietally expressed) content of non-enzymatic antioxidant viz flavonoids (functioning also as successors) and seed deterioration during post harvest storage. The data shows that extent of cell damage and thus seed viability is related to the varietal difference in flavonoids accumulation in mature rice seed. Low storer/viable varieties show lower content of flavonoids and higher oxidative damage in stored seed.