EFFECTS OF SOYBEAN LEAFLET TYPE ON NET CARBON DIOXIDE EXCHANGE, WATER USE, AND WATER-USE EFFICIENCY

Abstract

Two near-isogenic soybean (Glycine max (L.) Merrill) lines with normal and narrow leaflets were compared in the field for differences in net carbon dioxide exchange rates, water use, and water-use efficiency with various combinations of population and row spacing. Net carbon dioxide exchange was determined with an open field chamber system and infrared gas analyzer. Water use was estimated from neutron attenuation readings and precipitation. Leaflet type did not significantly affect net carbon dioxide exchange, water use, or yield. Water-use efficiency was only affected at 53 plants/m² in 38-cm rows, with greater efficiency for the narrow-leaflet cultivar.