All my biggest yielding strains have been haze crosses (Neville's Haze or Super Silver Haze crosses, to be more precise). I had one particular Sensi Star plant that grew huge - half a pound - but that was still only half as big as my biggest haze (15oz). And it was a sativa-leaning pheno. The Sensi Star Afghan pheno in my keeper collection (short, squat, leafy) yields around 5oz per run. By comparison, my Stinky Cat Piss Haze yields no less than 10oz per run, and averages about 12oz. The Stinky Cat Piss finishes in 9-10 weeks and the Sensi Star goes 9 weeks. I've been growing some Shishkaberry crosses from Chimera that have grown well - up to about 7oz - and finished in just under 8 weeks.
I'm not particularly a yield grower - all my keeper clones have been chosen for their high - but sativas do tend to do much better in my system than indicas. There a few reasons for this: I have 6' of head height with two 600w lamps hanging one on top of the other - the sativas can take advantage of this head height; most indicas tend to be a lot squatter and leafier, which hurts side-light penetration; sativas tend to be branchier, so are easier to vertically scrog; indicas don't stretch as much, so they have less room to "fill in" in-between nodes (which all my sativas do); sativas tend to flower for a week or two longer than indicas; and I find a lot of indicas are more sensitive to nutrients and simply don't grow as fast or with the same vigour.
Obviouly I'm generalising, as there are some indica hybrids out there that are renowned for their yield and vigour, but again they tend to be at least 50% sativa. I don't know many mostly indica varieties that yield that well. Of course, I've tended to grow a lot more sativas over the years than indicas, but it's a bit of a "chicken and egg" situation: sativas do better in my set-up, so that's what I grow. And I love me a haze high - so that's what I enjoy growing and smoking most.
