The effects of environmental factors; soil texture, planting dates and ages at harvesting on the yields of plant canes from 15 trials under rainfed conditions were evaluated by multiple regressions. Each trail comprised of ten Kamphaeng Saen sugarcane varieties and KK3 (khon kaen3) standard varieties in RCBD (Randomized Complete Block Design) with three replications. The evaluations of multiple regression revealed the different effects on sugarcane varieties of each environmental factor.