Plant population density, row spacing, and hybrid effects on maize canopy architecture and light interception

MADDONNI, G.A.; OTEGUI, M.E.; CIRILO, A.G.

FIELD CROPS RESEARCH

Elsevier

Lugar: Amsterdam; Año: 2001 vol. 71 p. 183 - 193

0378-4290

Light attenuation within a row crop is influenced by canopy architecture which has to be defined in terms of the size, shape, and orientation of its components (i.e., shoot organs). Cultural practices aimed to improve the efficiency of light interception (e.g., plant population and row spacing) affect canopy architecture through modifications in one or more of its components. Our objective were to: (i) make a hierarchy of the effects of contrasting plant population densities and row spacing on canopy components and (ii) analyze light attenuation within fully developed maize canopies. Field experiments were conducted at Pergamino (33°56’S, 60°34’W) and Salto (34° 33’S, 60° 33’W), Argentina on silty clay loam soils (Typic Argiudoll) during 1996/97 and 1997/98, without water or nutrient restrictions. Four hybrids of contrasting plant type were grown at 3 plant densities (3, 9 and 12 plants m-2) and two row spacings (0.35-m and 0.70-m). Among canopy components, leaf growth and leaf azimuthal orientation were the traits most affected by treatments. An interaction between hybrid and plant rectangularity on leaf azimuth was determined, and two types of hybrids could be identified for this trait, rigid and plastic. When maximum GLAI was attained light attenuation did not vary among hybrids and row spacing for plant populations ³9 plants m-2 (k coefficient: 0.55 and 0.65 for 9 and 12 plants m-2 respectively). A more uniform plant distribution increased light attenuation (k coefficient: 0.37 and 0.49 for 0.35-m and 0.70-m respectively) only when crop canopies did not reach the critical GLAI.