The plant growth regulator mepiquat chloride (MC), commercially sold as Pix^®, foliar fertilizers, and commercially available cytokinin products have been researched in the Trans-Pecos, Concho Valley (San Angelo), Permian Basin and El Paso Valley for six years in 24 separate tests, with 123 treatments under varying rates and application times, varieties and growing conditions to better define when and if MC, foliar fertilizers and/or cytokinins increased cotton yields. Summarization of these test show a distinct advantage in using MC when the height of the untreated upland cotton plant is expected to be over 24 inches (61 cm) at harvest. In 13 tests with 38 treatments, 83.3% of the treatments produced a yield increase of 10.62% over the UTC. When plants were less than 24 inches (>61 cm), 70.5% of the 17 treatments in 7 tests had an average reduction in yield of 9.23% compared to the UTC. MC in pima S-6 produced a yield increase of 7.5% over the UTC in 78% of 5 tests and a yield decrease of 7.3% in 2 tests.

Sixteen foliar urea tests produced a 5.3% yield increase in 75% of the tests and 5.4% decrease in 3 tests. One test on stressed cotton produced a 14.2% decrease. Cytokinins had a yield decrease of 6.8%in 15 tests, while 6 tests produced an increase of 3.4%.