Greetings from down here, Don. For the first time for a good few years things are ticking along relatively nicely here at this stage. August is usually our crunch month for moisture stress, and at this stage has been kind "here". We are about a month away from the predicted hatchings of what is expected to be a really major locust plague, and just heading into the period where cereal rusts are likely to become an issue. Nobody is quite sure what is likely to happen in regard to the two threats I have mentioned. No choice but to simply take it day by day. So we aren't out of the woods yet, but neither have we been cut off at the knees as seemed to happen so much in the last run of seasons.

There is no doubt that tillering IS affected by population density, and it is a technique suggested to us as a means of managing late season moisture stress, which is more the norm "here" than the exception. The theory is that a relatively high population limits the amount of secondary tillers produced. The secondary tillers are the first to be aborted as moisture stress increases, so a plant with fewer secondary tillers concentrates on production from the primary tillers with the theoretical result of less shrivelled grain. Theoretically it's desirable to have a high population of plants each supporting a lower number of primary tillers I think the theory has has some merit in wheat. I dont think it really does so much in barley, which is the other main cereal grown "here". Even tho i said i think the theory has some merit in wheat, I am less sure about its practical application, BUT thats "here" and in an environment which I have stressed to be quite different, with lower possibilities and expectations of production.

The trial data I have seen supporting the theory described above is quite old, so would have been done on narrower  row spacings of around 7 inch I would expect. I don't know what might have been done for wider row spacings.