Sweet Corn Shelf Life?

So, it’s “local” sweet corn season here in CT. Around here, starting around May, we start to see corn shipped in to markets from Florida first then Georgia. They are sold as “Super Sweet” varieties that hold their sugar content for a much longer period of time than “local” varieties supposedly do. Recently, I was surprised to see a sign in a vendor’s stand at a nearby farmer’s market that read “Super Sweet Corn”. Now I’m wondering if it is a true super sweet variety or just a claim that their corn was super sweet that day. Nowadays, local corn differs from the corn from FL & GA mostly in texture, it’s much tenderer, sweetness however can be quite similar. I know scientists are constantly tinkering with corn seeds to improve the yields, sweetness, disease resistance etc. so is it true that modern varieties of locally grown corn still have a very short shelf life? The old farmer’s saw was that you boiled the water first and then picked the corn. I wonder if that's still valid?

How long does modern freshly picked “local” corn hold it sweetness under refrigeration? Hours, days, weeks? Is it specie specific? Thanks!