Table 9.

Regression coefficients and their standardized values of ear level components for crop yield changes during 2003–2017 national summer maize trials.

Regression	Item	Ear number per area gap	Ear kernel weight gap	R2
Coefficient	Min	0.134	3.52	0.70
Coefficient	Max	0.156	4.31	0.74
Coefficient	Mean	0.149	3.89	0.72
Standard coeff.	Mean	0.61	0.98