Table 1. Traits involved in maize grain yield based on literature.

Type of treatment	Country	Authors reference	Sophisticated randomization layouts*
Defoliation, plant densities, hybrids	Iran	[21]	RCBD/split-split plot arrangement
Defoliation, Restricted pollination	Argentina	[22]	RCBD
Hybrids	Argentina	[23]	RCBD
Plant densities, hybrids	Argentina	[24]	RCBD
Hybrids	India	[25]	RCBD/split plot arrangement
Plant densities, Restricted pollination, hybrids	USA	[26]	strip plots
Hybrids, nitrogen levels	Argentina	[27]	RCBD included a combination of three factors
Defoliation, kernel removal	USA	[28]	RCBD
Hybrids	Canada	[29]	RCBD
Plant densities, Restricted pollination, hybrids	USA	[30]	RCBD
Shading, thinning, hybrids	Argentina	[31]	RCBD
Hybrids	USA	[32]	RCBD

^*RCBD: Randomized Complete Block Design.