Yield responses by modern wheat genotypes to phosphate fertilizer and their implications for breeding

Summary The response to phosphate fertilizer by modern wheat genotypes was examined in the field under natural rainfall in three seasons. Models were developed which show that grain yield was positively correlated with biological yield and harvest index. In one of the seasons, which was relatively dry, shorter statured wheats gave higher yields at each level of applied phosphate. Higher levels of phosphate tended to offset the reduction in yield associated with late heading and the importance of biological yield on grain yield. The genotypes which produced the largest number of grains m^-2 produced the highest yields.Implications for plant breeding programs are discussed.