Field Experiment -testing hypothesis that the response of winter wheat grain yield to sowing date is dependent on variety.

 You have been given the task of designing a field experiment to test the hypothesis that the response of winter wheat grain yield to sowing date is dependent on variety. You have 3 candidate varieties, and the range of sowing dates to be tested is from 15th September to 30th October. Describe succinctly how you would select an appropriate experimental design, the field layout, the treatment combinations, the number of replicates, and the size and shape of plots. Give relevant citation in the coursework.