genetics, environment, and ? random gene expression?

[bower]

Originally Posted by maf

I wouldn't attach too much significance to the spacing of the first pair of leaves, in my experience it can vary.

Yes, I'm just looking for an explanation of the early variance. And looking for early selection cues for my own purposes, within a (presumed) homozygous batch of seedlings. I saved seed from the 'leafy' type plant last year because it was a more compact growth habit and big clusters of fruit early on. I didn't expect the seed to produce any 'leggy' type plants.

Originally Posted by maf

Observe for a few more internodes and confirm the pattern is repeating. Are there any other differences between the plants?

One thing I noticed is that the 'leggy' ones' stems are a bit more slender than the 'leafy', and their height is more uniform between both batches of seed - one of which was started a day earlier. In the 'leafy' group, the two plants with a day's head start are noticeably taller than the others.
There's certainly no detectable difference in leaf shape - although maybe PL's are more uniform in leaf shape than RL types. I'm growing a number of other PL's this year, and it would be hard to tell any of them apart at this stage. Whereas the RL's are all distinctive, even when small.

I moved half of each group to larger pots today - didn't notice any difference in root volume.

Originally Posted by maf

If there is a genuine difference in phenotype between the plants, one possible explanation could be that the vigorous and productive plant from 2011 was an F1 hybrid; an accidental cross-pollination that occurred in the seed supplier's mother plant; and any differences you are now seeing are the natural segregation of the F2 population.

This seems less likely, since both 'leafy' and 'leggy' plants were produced by the original batch of seeds and also had the same fruit shape and size, recessive colouring, and quality of fruit. It would have to be a cross with a virtually identical variety.

Thanks for your advice! I guess I'll have to grow out at least one of each, and see whether these differences are maintained as they get bigger, in the way that they did from the original seed source.