91 WORKSHOP 8 (Abstr. 1042-1045) Seed Vigor Testing and Utilization
91 WORKSHOP 8 (Abstr. 1042-1045) Seed Vigor Testing and Utilization
91 WORKSHOP 8 (Abstr. 1042-1045) Seed Vigor Testing and Utilization
flower seeds, e.g., summer sowing for fall planting or winter sowing for spring planting. Vigor tests help determine failures in emergence and stand establishment and identify the level of physiological aging of a seed lot and its potential for the
Abstract
It is beyond the purpose of this presentation to review all the definitions for the term “vigor” as applied to seeds. So far, no one definition has been accepted, and perhaps it is not yet time to settle on one definition until we know more about the subject.
The environment that seeds experience during development, storage, and planting significantly affects seed vigor. Yet, relatively few studies have focused on how environment during seed development affects seed vigor. Our objective was to compare vigor of seeds developed in summer vs. winter. Lettuce (Lactuca sativa L.) seeds from six cultivars were developed in summer and winter at Yuma, Ariz. Seed vigor of these seedlots was compared using field plantings and growth chambers (at 20, 25, 30, and 35C). Seed vigor was greater for seed produced during summer than for that produced during winter, based on greater field emergence, higher germination percentages, and longer roots. These seedlot differences in vigor were greatest at 35C. Another way to estimate seed vigor is by ion leakage from seeds. Fewer ions leaked from seeds produced in summer than from those produced in winter. Thus, lettuce seed is more vigorous when produced in summer than in winter, and ion leakage is a good indicator of that vigor.
Both seed viability and vigor directly affect the performance of seeds planted to regenerate the crop. Although seed quality can influence many aspects of performance (e.g., total emergence, rate of emergence), this presentation will primarily examine the relationship of seed vigor to one aspect of performance - crop yield. Reductions in yield can be indirectly related to low seed vigor if the low vigor seed results in plant populations that are below a critical level. Thus, we investigated the direct effects of seed vigor on yield in the absence of population differences for annual crops that are harvested at three stages; during vegetative growth, early reproductive growth or at full reproductive maturity. Seed vigor affects vegetative growth and is frequently related to yield in crops that are harvested during vegetative growth or during early reproductive growth. However, there is usually no relationship between vigor and yield in crops harvested at full reproductive maturity because seed yields at full reproductive maturity are usually not closely associated with vegetative growth. The use of high vigor planting seed can be justified for all crops; however, to insure adequate plant populations over the wide range of field conditions which occur during emergence.
Previous experiments showed that a 10 day aerated water soak (water priming) increased red oak (Quercus rubra) seed vigor. After water priming most seed had split pericarps. Seed with split pericarps were observed to be more visorous than water primed seed without split pericarps. An experiment was conducted to determine if pericarp splitting could be used as an indicator of red oak seed vigor. The following experiment was conducted. Red oak seed from three open pollinated, half-sib families, were water primed for 10 days. Seed were separated into two groups, seed with split pericarps and without split pericarps, and a germination test conducted. Unprimed seed were used as a control. There were significant differences among the families in seed vigor (germination completeness, uniformity and speed). Primed seed with intact pericarps had lower seed vigor than primed seed with split pericarps and unprimed seed. The results suggest that pericarp splitting following water priming is an indicator of high seed vigor.
Poster Session 17–Seed and Stand Establishment 19 July 2005, 12:00–12:45 p.m., Poster Hall–Ballroom E/F
1 To whom reprint requests should be addressed. Current address: Bodger Seeds, 1851 W. Olive, Lompoc, CA 93436. Journal paper no. J-14892 of the Iowa Agriculture and Home Economics Experiment Station, Ames