yellowish seed leaves on 1 seedling

[RomanX]

WHY??? And how to correct?

Only 1 tomato seedling (out of ten) does not have the normal green seed leaves like the others; ALL the tomato seedlings are under lights.

This is the only seedling for this particular variety (Legend) and it is a favorite of mine that I have started and grown for the past three years. Seedlings from previous years have had the normal seed leaves.

I'm hoping it's not a serious sign, that this seedling will still grow and produce normally, as it is my last seed . . . it's too late to re-order and start for this season.