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- Author or Editor: Héctor Pérez x
- HortScience x
We investigated the response of Gaillardia pulchella seeds to desiccation and aging stress to gain some perspective on the germplasm storage potential and seed vigor of this species. Seed–water relations of mature, freshly harvested G. pulchella seeds were characteristic of desiccation-tolerant species. For example, initial seed water potential (−53 MPa) was well below the lethal water potential limit (−15 MPa) for desiccation-sensitive seeds. Desiccation tolerance was confirmed by high (>70%), rapid (t 50 range 4–7 days), and uniform germination following equilibration drying. Likewise, post–saturated salt accelerated aging (SSAA) germination tests indicated a high degree of vigor of fresh seeds. The substantial level of desiccation and aging-related stress tolerance in G. pulchella seeds suggests that these organs potentially display orthodox storage physiology and an ability to endure variable seed bed conditions.
The perennial nature, prolific white to pink racemes, and attractive foliage and form of october flower [Polygonella polygama (Vent.) Engelm. & A. Gray] and sandhill wireweed [Polygonella robusta (Small) G.L. Nesom & V.M. Bates] suggest that these wildflowers could have significant ornamental and landscape potential if an effective propagation method could be developed. However, a paucity of seed biology information exists for these species. Two- to 4-month-old seeds of both species were tested for viability using triphenyltetrazolium chloride (TZ) before germination experiments. Initial viability of seed lots was 77.4% ± 6.3% and 53.5% ± 6.8% for october flower and sandhill wireweed, respectively. Initial germination tests showed that both species had the highest number of germinated seeds in cool temperatures (22/11 °C day/night), but a portion of the seed population remained dormant. Germination of both species at simulated seasonal temperatures indicated that seeds require a warm, moist period (warm stratification) before germination starts at cooler temperatures. Germination of both species also increased when gibberellic acid (GA3) was applied at the highest rate of 1000 ppm. We conclude that seeds of both species exhibit non-deep physiological dormancy.
Demand for butterfly milkweed (Asclepias tuberosa L.) has increased in recent years. However, seed production practices are not well-defined. We partnered with a wildflower seed producer to investigate the effects of weed barrier cloth, plot shading, mature follicle harvest timing, and dry–cold stratification on seed production and germination. Weed cloth had no impact on seed production. However, shading decreased the number of seeds produced by 1.2- to 9.6-fold. Seeds harvested in July and August showed 2.9- and 2.3-fold improvements in total germination and more uniform and rapid germination compared with September-collected seeds. Conversely, seeds exposed to dry–cold stratification displayed a 3.0-fold reduction in the germination rate compared with nonstratified seeds. Our results indicate that the production system significantly impacts seed production and quality of A. tuberosa. Seed producers can use weed barrier cloth to facilitate seed collection from shattering follicles and suppress weeds without a considerable loss of seed production. However, plants should not be grown under conditions of additional shade. Furthermore, high-quality A. tuberosa seeds can be collected earlier in the year, but they should not be subjected to dry–cold stratification.
Small- to midsized farmers in the southeastern United States have expressed interest in reigniting on-farm seed production of regionally adapted high-value vegetable crops. However, a considerable knowledge gap exists related to how locally produced seeds perform in the region. We investigated how the first generation of local, farm-produced seeds compared with the original, nonlocal, certified commercial seed stock in terms of initial germination, seedling vigor, and subsequent vegetative traits of ‘Yukina Savoy’ (Brassica rapa L.), an heirloom Chinese cabbage. Locally produced seeds consistently outperformed seeds of the commercial lot. Germination for local and nonlocal seeds reached 99% and 94%, respectively. However, locally produced seeds germinated 1.5-fold more rapidly than nonlocal seeds, and germination was more uniform in local seeds. Seedlings produced from local seeds appeared more vigorous and displayed a significant height advantage compared with nonlocal seeds when grown in the greenhouse. Likewise, transplants from local seeds maintained an advantage over transplants from nonlocal seeds for plant vigor, growth traits, and harvestable yield during the 4-week field cultivation period. We conclude that production of high-quality ‘Yukina Savoy’ seeds is possible in the southeastern region despite challenging environmental conditions and varied farming practices of our partners during the seed production cycle.