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Effects of maternal plant invironment on lettuce (lactuca sativa l.) seed dormancy, germinability, and storability

Contreras, Samuel A.

Abstract Details

2007, Doctor of Philosophy, Ohio State University, Horticulture and Crop Science.
Seed dormancy, germinability and storability are important aspects of seed quality determined by the genotype and environment during seed development. Lettuce is one of the most important vegetables in the world and high quality seed is required for successful crop establishment. However, seed thermoinhibition and photodormancy are two properties commonly affecting germination speed and uniformity of many lettuce genotypes. The main objectives of this study were to determine the effects that maternal plant conditions have on different aspects of lettuce seed quality such as germinability and storability. In separated experiments, ‘Tango’ lettuce seeds were produced in contrasting conditions for the following environmental factors: i) water availability, ii) day-length, iii) light quality (red to far-red [R:FR] ratio), and iv) temperature. Restricted water availability during lettuce seed production had little effects on most aspects of seed quality, although a significant increase in seed weight and the production of fewer seeds per plant were observed. Additionally, water productivity (seed yield per volume of water consumed) increased significantly in response to restricted water availability, which is especially important for lettuce seed producers which are located mainly in arid regions. Seeds produced at higher temperatures (30/20°C vs. 20/10°C) had higher storability and lower thermoinhibition, photodormancy, and dry weight. Temperature effects on seed germinability occurred during the first phase of seed development (cell division and histo-differentiation), while effects on seed storability occurred at the last phase of seed development (maturation drying). The aspect of the maternal plant light environment that had the greatest effects on seed quality was the R:FR ratio. Seeds produced under higher R:FR ratios had higher germinability, poorer storability, lower sensitivity to external abscisic acid (ABA), and lower ABA concentrations. These effects occurred during the last phase of seed development (maturation drying, after physiological maturity) and I hypothesized that higher accumulation of the active form of phytochrome (Pfr) in seeds drying under red-rich light would be involved in these responses. My results suggest that seed production under light environments with higher R:FR ratios represents a novel approach to the production of lettuce seed with lower levels of thermoinhibition and photodormancy.
Mark Bennett (Advisor)
148 p.

Recommended Citations

Citations

  • Contreras, S. A. (2007). Effects of maternal plant invironment on lettuce (lactuca sativa l.) seed dormancy, germinability, and storability [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1196451272

    APA Style (7th edition)

  • Contreras, Samuel. Effects of maternal plant invironment on lettuce (lactuca sativa l.) seed dormancy, germinability, and storability. 2007. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1196451272.

    MLA Style (8th edition)

  • Contreras, Samuel. "Effects of maternal plant invironment on lettuce (lactuca sativa l.) seed dormancy, germinability, and storability." Doctoral dissertation, Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1196451272

    Chicago Manual of Style (17th edition)