Evaluation of Planting Date Effects on Crop Growth and

A single field study was conducted in 1995 at the Marana Agricultural Center (2000 f elevation) to evaluate the effects of three planting dates on yield and crop development for one Pima and two Upland varieties. Planting dates ranged from 6 April to 18 May (469-931 HU /Jan 1 86/55 ° F thresholds). Crop monitoring revealed vegetative growth tendencies with later plantings. General trends showed decreasing lint yield with the later (18 May) plantings for all varieties. Early plantings (6 April) however, for both Pima S-7 and DPL 20 resulted in slightly lower yields than the later two planting dates. This reduced yield for planting date 1 can be explained by extremely cool weather conditions which occured immediately after planting and in- season fruit loss which impacted the final fruit retention levels