Poorly Drained Conditions and Root Development of Eight Indeterminate Soybean Cultivars1
- J. A. Stone2
The productivity of soybeans [Glycine max (L.) Merr.] grown on the poorly drained, finely textured soils of southwestern Ontario is often limited by excess spring rainfall. Identifying cultivars able to withstand these conditions may improve productivity. The objective of this experiment was to determine if the effect of poorly drained, non-flooded conditions on the early root growth of soybeans varies between cultivars. ‘Amcor’, ‘Beeson 80’, ‘Corsoy’, ‘Hawkeye 63’, ‘Harosoy 63’, ‘Kentland’, ‘Premier’, and ‘Wayne’ soybean cultivars were evaluated. Drainage treatments were imposed by maintaining 0.0 to 0.002 m or 0.002 to 0.0028 m aggregate fractions of Brookston clay loam (clayey, mixed, mesic Typic Haplaquolls) at < 0.02 MPa suction. Plants were grown until 21 days after emergence in 0.0762 m i.d. by 0.92 m long acrylic tubes immersed in 23 °C constant temperature baths located in a controlled environment room. Daytime (16 h) ambient temperatures were maintained at 27 °C and night temperatures at 20.0 °C. Response variables analyzed were the rate of taproot and lateral root extension with time, the number of upper lateral roots with depth, and top and root dry weight. The poorly drained treatment significantly reduced the rate of taproot and lateral root extension; however, the magnitude of the response varied between cultivars. Premier and Harosoy 63 exhibited the largest and Corsoy the smallest reduction in root extension. The number of upper lateral roots was not significantly affected by the drainage treatments. The top/root ratio was significantly higher for the poorly drained treatment due to a greater reduction in root than in shoot dry weight. The results indicate that soybean cultivars differ in their ability to withstand poorly drained conditions during vegetative growth.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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