Soybean Nodulation as Influenced by Seedling Vigor1
- R. S. Smith and
- M. A. Ellis2
Nodulation in soybeans [Glycine max (L.) Merr.] is influenced by environmental, rhizobial, and host symbiont factors. This investigation was conducted to determine the effects of seedling vigor on early soybean nodulation. Seed quality of three soybean cultivars was adjusted using the accelerated aging technique in order to provide seed lots with a high degree of variation in seedling vigor. Seedling vigor was defined as the number of days from planting to emergence. Aged seeds planted in both a sandbench and the field were uniformly inoculated in the furrow with a Rhizobium japonicum liquid inoculum. Days to seedling emergence was negatively correlated with plant top weight, number of tap root nodules, total number of nodules, and nodule dry weight per plant. Significant decreases in the number of tap root nodules and total number of nodules were observed in a sandbench trial between each of the three earliest emerging treatments (4, 5, and 6 days after planting). In all cases, the first plants to emerge had significantly more tap root nodules than the last plants to emerge. Significance in number of nodules/plant and nodule weight/plant between these two treatments was observed in six of the eight instances.
The results suggest that soybean nodulation may be influenced by seedling vigor and that seedlings with uniform vigor should be utilized when conducting nodulation evaluations.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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