Can anybody tell me what is going on with the corn, it has one main stalk and two side stalks that seem quite robust, also what are the purple streaks? This is from one seed only, by the way.

Could the extra stalks be an indication of potential ear count?

dude i have the same dang thing! I'm new to gardening but have never heard of corn doing this! I'm using a basic yellow/white sweetcorn hybrid i baught at the local supermarket, nothing special. i too have up to 2 sidestalks on almost every stalk of corn that has come up!

I always remove these suckers, they detract nutrient from the rest of the plant. The cobs which may form on them will be inferior anyway and will not amount to anything. Best to cut them off.
To get a better number of cobs per plant, (my best is 5 off 1 plant, average is 3), wait until the secondary roots develop , that's those big ones that come out from the base of the plant, often above ground level. Once these roots are growing, bury half of the stalk in compost, well rotted manures and mulch. So if your plants are a metre high, you can put half a metre of goodies under them. This will feed the secondary root system which is capable of taking up large amounts of the good stuff. They also require plenty of water for this to work properly. Normally you would expect this to rot the stems on most plants but on sweet corn that is not the case. It will also be a great additive to the beds for the following crop.

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The secret is the soil.