. 2021 Sep 22;12:707852. doi: 10.3389/fpls.2021.707852

TABLE 2.

Significance of fixed effects and interactions for crop response variables as a function of plant density and sweet corn hybrid for (A) Yield and Ear traits, (B) Growth and Development traits, and (C) Physiological traits at Urbana, IL in 2018–2020.

(A) Yield (area-wise and per plant) and ear traits
		Area yield			Yield per plant		Ear traits
Main effects		Per-area marketable ear mass	Kernel mass	Crate yield	Per-plant marketable ear mass	Marketable ears	Ear length	Filled ear length	Recovery
		Mt/ha	Mt/ha	Crates/ha	kg/plant	no./plant	cm	%	%
Plant density (D)		^**	^**	^**	^**	^**	^**	^**	^**
	Low	7.6	3.2	413	0.73	2.0	19.5	18.7	39.4
	High	14.4	6.9	1,064	0.18	0.7	18.3	16.7	41.1
Hybrid (H)		^**	^**	^**	^**	^**	^**	^**	^**
Interaction
	DxH	^**	NS	^**	^**	^**	^*	NS	NS

(B) Growth and development traits

Main effects		Flag leaf height	Primary ear height	Tiller number	Leaf number	Leaf angle	Leaf Area Index	Shoot biomass	Days to silking	Anthesis-silking interval
		cm	cm	no./plant	no./plant	degrees	–	g/plant	GDD	GDD

Plant density (D)		^**	^**	^**	NS	^**	^**	^**	^**	NS
	Low	152.9	54.1	2.2	14.9	41.8	2.12	1.17	1,305	104
	High	165.9	61.6	0.8	14.8	38.3	4.14	0.37	1,324	104
Hybrid (H)		^**	^**	^**	^**	^**	^**	^**	^**	^**
Interaction
	DxH	NS	NS	^**	NS	NS	^**	^**	NS	NS

(C) Physiological traits (leaf gas exchange measurements)

Main effects			Photosynthetic CO₂ assimilation			Stomatal conductance		Instantaneous water use efficiency

			μmol m^–2 s^–1			mol m^–2 s^–1		–
Plant density (D)			^**			^**		^**
		Low	40.0			0.386		116.4
		High	36.1			0.320		124.7
Hybrid (H)			NS			NS		NS
Interaction
		DxH	^**			^*		NS

All crop response variables were recorded for 15 different sweet corn hybrids (H) at two levels of plant density (D), namely, Low (9,900 plants/ha) and High (79,000 plants/ha).

^* and ^** denote significant effects at p < 0.05 and p < 0.01, respectively. NS stands for a non-significant effect.