Leaf area, light interception, and crop development in maize

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

FIELD CROPS RESEARCH

Elsevier

Lugar: Amsterdam; Año: 1996 vol. 48 p. 81 - 87

0378-4290

Few models used to estimate the fraction of photosynthetically active radiation intercepted by maize crops (flPAR) as a function of leaf area index (LAI) account for genotype differences and ontogenetic stage. In this study, the development of the fIPAR/GLAI relationship of three maize hybrids having contrasting plant type and grown in different environmental conditions was characterized. Three field experiments were conducted at Rojas (34"0SfS), Argentina, on a silty clay loam soil. without nutrient restriction. The effects of sowing date and water regime were tested. Plant density was always 7 plants - 1 m -. The fIPAR was calculated from measurements above and below the canopy, before and after maximum GLAI was attained. Hybrids differed significantly ( P < 0.05) in individual leaf area, leaf angle, and GLAI evolution. Exponential models adequately described (r´ > 0.77; n 2 2 15) the flPAR/GLAI relationship for pre-maximum GLAI data of all hybrids. Nevertheless. maximum fIPAR was always below values quoted in the literature (< 0.90). and differences were detected among hybrids in the attenuation coefficient ( k ) that were probably related to leaf angle and leaf area. For hybrids with a similar leaf angle at all leaf positions no difference existed in the fIPAR/GLAI relationship along the cycle (pre- and post-maximum GLAI). The relationship changed after tasselling for the hybrid with erect upper leaves. Ignoring such differences could be misleading when iIPAR/GLAI models are used to estimate canopy photosynthesis and hence biomass production. radiation-use efficiency, and kernel set of specific hybrids and growth stages.(34"0SfS), Argentina, on a silty clay loam soil. without nutrient restriction. The effects of sowing date and water regime were tested. Plant density was always 7 plants - 1 m -. The fIPAR was calculated from measurements above and below the canopy, before and after maximum GLAI was attained. Hybrids differed significantly ( P < 0.05) in individual leaf area, leaf angle, and GLAI evolution. Exponential models adequately described (r´ > 0.77; n 2 2 15) the flPAR/GLAI relationship for pre-maximum GLAI data of all hybrids. Nevertheless. maximum fIPAR was always below values quoted in the literature (< 0.90). and differences were detected among hybrids in the attenuation coefficient ( k ) that were probably related to leaf angle and leaf area. For hybrids with a similar leaf angle at all leaf positions no difference existed in the fIPAR/GLAI relationship along the cycle (pre- and post-maximum GLAI). The relationship changed after tasselling for the hybrid with erect upper leaves. Ignoring such differences could be misleading when iIPAR/GLAI models are used to estimate canopy photosynthesis and hence biomass production. radiation-use efficiency, and kernel set of specific hybrids and growth stages.