Models of yield and plant population of sunflower

Abstract

By re-examination of eight years' data at four locations in the U.S.A. and three locations in China on yield and plant population of sunflower, five mathematical models of the relationship between yield and plant population of the crop and determination of the optimum population and maximum yield of sunflower were developed. They are: (1) y = a exp(bx); (2) Y = a x exp(bx); (3) xopt = 1b; (4) yx.opt = ae; (5) ymax = xoptae (y: yield per plant; x: plant population; exp(bx); exponential function of bx; Y: yield per unit area; xopt: optimum plant population; yx.opt: yield per plant from the optimum plant population; Ymax: maximum yield from the optimum plant population; a, b: coefficients of the models). The least square method was adopted to determine the coefficients of the models, and the models passed consistently the test of significance, so that the optimum plant population and maximum yield of sunflower determined by the models are very precise and the models are absolutely dependable.