Early growth and devlopment response to corn to canola competition and shade stress

Authors: MORILES, JANET - SOUTH DAKOTA STATE UNIV; CLAY, SHARON - SOUTH DAKOTA STATE UNIV; CLAY, DAVID - SOUTH DAKOTA STATE UNIV; Horvath, David; HANSEN, STEPHANIE - SOUTH DAKOTA STATE UNIV

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/9/2009
Publication Date: 2/1/2009
Citation: Moriles, J.C., Clay, S.A., Clay, D.E., Horvath, D.P., Hansen, S. 2009. Early Growth and Devlopment Response to Corn to Canola Competition and Shade Stress [Abstract]. Weed Science Society of America Meeting Abstracts. #47.

Interpretive Summary:

Technical Abstract: Corn-weed competition studies indicate that resource limitation slows normal corn growth and development and often results in lower yields. However there is minimal information on the physiological basis of crop competition, especially at the early growth stages when resources would be expected to be plentiful based on plant size. The research objectives of this study were to determine if gene expression and physiological responses of corn at the V2 and V4 growth stages differed when grown under optimal vs stress conditions. Stress treatments were 1) low N; 2) 40% shade applied at crop emergence and removed fromV2 toV8, and 3) canola planted in rows close to corn (to mimic weed stress) at corn planting and removed from VE to V8. At V2 and V4, corn height, leaf area, plant biomass, and chlorophyll content were measured and leaf tissue sampled for microarray analysis. Preliminary results show that corn plants grown under 40% shade had the least leaf area, biomass, chlorophyll content, and were shorter than corn grown alone or with canola at both sampling times. When shade was removed at V2, plants analyzed at V4 had less leaf area, biomass, and were shorter than nonstressed plants. Corn plants grown with canola removed from VE to V6 were similar in height and chlorophyll content as corn grown alone. At harvest, corn yield losses compared to the optimal treatment were only measured in two treatments, where canola was allowed to remain until the V8 stage or when grown under low N conditions. Based on very preliminary microarray data from V2, corn gene expression differed among the optimal, shade, and canola treatments. When corn was stressed with canola, multiple genes that regulate early light inducible proteins (ELIP) were induced whereas when corn was light stressed, several genes that regulate Photosystem II proteins were induced. These data appear to indicate that the physiological responses of corn to weed or light stress differ.