Table 7.

Models performance and F-test.

Model Expression	R2	RMSE(kg/ha)	F	1% level of significance
y = -0.60 + 1.55x3	0.75	228.04	58.51	YES
y = -1.45 + 2.65x3-0.26x5	0.80	205.74	36.11	YES
y = -1.06 + 0.20x2 + 2.04x3-0.23x5	0.83	189.13	27.94	YES
y = -1.02 + 0.23x2 + 1.97x3-0.14x5-0.10x6	0.84	185.84	20.57	YES
y = -1.04 + 0.24x2 + 2.08x3-0.13x4-0.13x5-0.08x6	0.84	185.46	15.50	YES
y = -0.98-0.12x1 + 0.28x2 + 2.18x3-0.23x4-0.11x5-0.06x6	0.84	185.45	12.06	YES