Moisture-Stress Effects on the Yield Components of Two Soybean Cultivars1
- N. N. Momen,
- R. E. Carlson,
- R. H. Shaw and
- O. Arjmand2
Limited soil moisture influences field crop performance by reducing plant height, the size of the assimilating leaf area, and the size and number of potential storage sites for produced dry matter. The effect of moisture stress on plants is complex and very dependent on the stage of development. Therefore, soybeans (Glycine max (L.) Merr.) cultivars ‘Hark’ and ‘Rampage’ were in grown in the field in large potometers filled with the top 15 cm of a Nicollet loam (Aquic Hapludolls, fineloamy mixed mesic). The plants were subjected to four independent moisture stress periods during critical reproductive stages of growth. Soil moisture was controlled by hand watering and the use of an automatic weather shelter, which covered the plots during periods of rainfall. Soil moisture was measured with a neutron soil-moisture probe, and frequent leaf-water potential and leaf diffusive resistance measurements were collected to document moisture stress. Final seed yield and components of yield were determined at maturity for all experimental units.
Moisture stress significantly affected most components for both cultivars during the four stress periods, but important cultivar moisture stress interactions were difficult to identify. Although these two cultivars differed greatly in some specific components of yield (Le., seed number, seed size, etc.), compensation between the different yield components resulted in no consistent yield differences between these two cultivars.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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