Shifting undesirable correlations

Wheat functions as a complex well-integrated organism with adaptation to many environments. Traits of wheat may be correlated to each other in a positive or a negative manner. The direction of the correlation is independent of breeding objectives and may change from one production environment to another. Grain yield is correlated positively with time to maturity in environments without terminal stress. The negative correlation between grain yield and grain protein concentration exemplifies an undesirable relationship in a wheat quality type in which protein concentration is positively correlated with bread loaf volume. However, this same correlation has an advantage to those end-products that are favored by low protein concentration such as confectionary products. To shift the negative correlation between grain yield and protein concentration requires assembling a more photosynthetically efficient, nitrogen-use efficient and\or water-use efficient genotype in combination or separately. Simultaneous selection for quantitative and quality traits is a breeding strategy, which with the inclusion of marker assisted selection, can shift undesirable correlations.