Seed Biotechnology Center
Seed Biotechnology Center
Seed Biotechnology Center
University of California
Seed Biotechnology Center

Seed Quality and Technology

Measurement of Single-seed Respiration Rates

Seeds vary in quality or vigor, and a number of vigor tests have been devised to assay seeds and provide relative rankings of seed lots. Seed respiration following imbibition is an indication of metabolic activity and is correlated with seed vigor. A new approach to respiration measurements called the Q2Technology ( allows the respiration rates of individual seeds to be measured. The respiratory activity of each seed is recorded over time, and Q2 software determines several parameters that characterize the respiratory patterns and the variation among seeds in these patterns. The Bradford lab has been working with the Q2 since 2006, funded by a grant from the Vegetable and Flower Seed Permanent Research Fund of the American Seed Trade Association and in-kind support from ASTEC. They have tested seeds of a number of species in the Q2 and conducted comparisons of Q2 values and other measures of seed vigor. Various aspects of the oxygen consumption curves provide information on seed quality, as characteristic patterns of respiratory activity are associated with seed vigor, priming and aging. The values characterizing these patterns are associated with the time of initiation of rapid respiration, the rate of respiration and the minimum oxygen level and were related significantly to seed vigor. The measurement of individual seeds also provides insight into the variability that can exist within seed lots that may not be evident in germination uniformity. Results from the studies were recently reported at the International Workshop on Seeds in Olsztyn, Poland and are being prepared for publication.

Genetic Basis of Lettuce Seed Thermoinhibition

Lettuce seeds are susceptible to thermoinhibition when planted at high temperatures, leading to failures or delays in germination and seedling emergence and resulting in yield losses and higher costs. The Bradford lab has been working to identify the genetic basis of this seed dormancy trait and to develop germplasm with reduced susceptibility to thermodormancy. The lab previously identified a quantitative trait locus (QTL) and an associated gene that regulates the temperature sensitivity of germination. The gene is involved in the biosynthesis of abscisic acid (ABA), which is a germination inhibitor. The lab also has shown that this gene (LsNCED4) is up-regulated during seed development and in response to high temperature. Global gene expression studies using the microarrays mentioned above have identified networks of genes whose expression is altered in lettuce seeds by high temperature. A second genetic population is also being developed to map and study other QTLs and genes that are involved in seed germination and quality traits. This work is supported by the USDA-CSREES National Research Initiative and by the National Science Foundation through the Compositae Genome Project.

DNA Extraction from Seeds

The SBC worked with seed industry partners to develop and verify high-throughput protocols for DNA extraction from seeds of a wide range of crops and seed types. The SBC developed an efficient system to grind and extract DNA from vegetable seeds. Protocols were developed to extract high-quality DNA from 11 seed types in a high-throughput format. The DNA can be used for variety identification, hybridity screening, marker- assisted selection, or other purposes. This project was funded jointly by a consortium of vegetable seed companies including Rijk Zwaan Breeding BV, DeRuiter Seeds Inc., Harris Moran, Hazera Genetics LTD., Sakata Seeds America, Seminis Vegetable Seeds, Sunseeds and Syngenta AG.

    Seed Extraction Supplement

High-throughput DNA Extraction from Seeds

Seed Science & Technology, Volume 34, 741-745

For information on obtaining the full article go to: Seed Science & Technology


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