Influence of Seed Size and Depth of Planting on Seedling Emergence of Two Milkvetch Species1
- C. E. Townsend2
The relationship between seed sire and seedling emergence was studied in cicer milkvetch (Astragalus cicer L.) and falcatus milkvetch (A. falcatus Lam.). Three sizes of seed of each species were planted at 1.3-, 2.5-, and 3.8-cm depths in both the greenhouse and the field. The three seed sizes were designated as large, medium, and small. Sterilized soil was used in the greenhouse. Plantings were made at Ft. Collins and Akron, Colo, in fallowed soil.
In both the greenhouse and the field there were significant differences among depths of planting for seedling emergence. In the field, seedling emergence was influenced by soil moisture conditions at planting time and by subsequent precipitation. Usually, the optimum average planting depth under such variable conditions was 2.5 cm for both species. Shallower seeding would be satisfactory, however, if the soil surface was moist at planting time. Seedling emergence was good from all three depths in the greenhouse and was much better than in the field.
In the greenhouse, seedling emergence from the large seeds was significantly better than from the small seeds for cicer milkvetch. Differences among seed sizes for seedling emergence, however, were slight and nonsignificant for falcatus milkvetch.
The relationship between seed size and seedling emergence was variable for both species at both field locations. In two of four studies with each species a significantly greater number of seedlings was obtained from the large seeds than from the small seeds. The variability was attributed to soil moisture conditions. In general, there appeared to be more promise of improving seedling vigor through selection for large seeds in cicer milkvetch than in falcatus milkvetch.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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