Zea mays is one be happy to inbred family.
Here is my limited understanding. Iâm no genetic or botany expert, but I know enough to keep most my seed pure.
There are 4 important genes for sucrose content in sweet corn. Standard (S) which is dominant and found in field corn. Open pollinated sweet corn (su), which is a recessive gene which increases sugar by about 50%. Super sweet contains the shrunken gene (sh-2) which doubles the sugar content over (su) corn. And finally sugary enhanced (se) sweet corn, containing an additional sugar-booster gene along with the (su) gene. Via hybridization, you can get both (se) and (sh-2) kernels on the same cob, leading to some of todayâs marketing âuber-sweetâ corns.
All of these gene are recessive except for the (S) and (se) gene. That means that a corn kernel will exhibit the most dominant trait of whatever it is pollinated with - (S), (su) or (sh-2), in that order. That is also decreasing sweetness and increasing starchiness. But, if the (se) gene is present, sugar will be boosted irregardless, which is why (se) sweet corns are the standard in corn country where time or distance isolation is not always possible.
Time isolation is best, but not always possible. I live in corn country. I have my small sliver of land and no way of predicting what the farmers on three sides of me are going to be planting. Because of that, I limit myself to just (se) sweetcorns. I try to get the earliest possible b/c field corn comes late, and I plant two varieties. Corn is mostly wind, and somewhat insect pollinated, so only time isolation or âbaggingâ is acceptable for saving pure seed. Bagging is how I approach my open pollinated popcorn, but I grow hybrid sweet corns for the (se) gene. I donât think this has been stabilized as an OP type yet.