Relationship between Laboratory Seed Quality Tests and Field Emergence of Common Bean Seed

摘要

In cool climates, early planting of bean (Phaseolis vulgaris L.) is recommended to assure a longer vegetative growth period. Early planting exposes seed to unfavorable conditions and the commonly used standard germination test cannot predict field emergence. The objective of this work was to examine the relationships between various seed quality tests and field emergence of common bean seeds. Thirty-nine strains and cultivars of bean were tested in the field and laboratory over 3 yr. Each year seed samples were tested in the laboratory and then planted in the field at very early, early, and at optimal planting dates. The viability of seeds was test by tetrazolium staining and was generally high; standard germination was above 80%, but germination in the cool test (at 10?°C) varied from 0 to 99%. The percentage of seeds with broken coats varied from 0.5 to 50.3 and conductivity ranged from 7 to 45 ??S cma?’1 ga?’1. Field emergence varied from 0 to 100%. Soil temperature at sowing appeared to be not only the most important environmental factor influencing field emergence but also a factor able to be used to differentiate the field emergence potential of a seed lot. Only the conductivity test could be used to predict seedling emergence in the field irrespective of soil temperature at sowing. At temperatures ranging from 9 to 15?°C, the first and the last count of the standard germination test and the broken seed coat test should be used in conjunction with the conductivity test to estimate field emergence potential.