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Commercial seed production of native grass and wildflower species can impoverish genetic diversity and change traits that are important for plant fitness when planted back into the restoration site (Pizza et al. 2021). During process of seed increase, populations are subject to sampling effects as well as unconscious artificial selection. Both processes can constrict genetic diversity and change the type of genetic variation present in the populations, resulting in phenotypes that may contrast sharply with those found in the wild. In particular, traits such as the timing, duration, or size of floral displays are affected, which could influence the value of the wildflower plantings for pollinators. Trait evolution can can occur during two steps in native seed production when: 1) seeds are collected from the wild, and 2) seed number is increased on a production farm. For example, genetic and trait diversity, such as the timing of flowering and seed maturation, may be lost when seeds are collected on a single date or when few plants are sampled. On the production farm, seed harvest at the peak of seed maturation may increase uniformity in reproductive traits, and machine harvesting may eliminate dispersal by selecting plants that do not shatter at maturity. Jointly, these two steps may curtail both overall genetic diversity, and alter traits in maladaptive ways. My students and I are exploring this idea by comparing plants grown from the wild populations that were used to establish cultivated populations and plants grown from commercial seed after the plants have been under cultivation for multiple generations at Native Ideals Farm. In addition, an undergraduate and I, Paige Fliehr, have distributed an international survey to native plant producers to determine key decisions they make that might affect genetic diversity in restoration materials.
Commercial seed production of native grass and wildflower species can impoverish genetic diversity and change traits that are important for plant fitness when planted back into the restoration site (Pizza et al. 2021). During process of seed increase, populations are subject to sampling effects as well as unconscious artificial selection. Both processes can constrict genetic diversity and change the type of genetic variation present in the populations, resulting in phenotypes that may contrast sharply with those found in the wild. In particular, traits such as the timing, duration, or size of floral displays are affected, which could influence the value of the wildflower plantings for pollinators. Trait evolution can can occur during two steps in native seed production when: 1) seeds are collected from the wild, and 2) seed number is increased on a production farm. For example, genetic and trait diversity, such as the timing of flowering and seed maturation, may be lost when seeds are collected on a single date or when few plants are sampled. On the production farm, seed harvest at the peak of seed maturation may increase uniformity in reproductive traits, and machine harvesting may eliminate dispersal by selecting plants that do not shatter at maturity. Jointly, these two steps may curtail both overall genetic diversity, and alter traits in maladaptive ways. My students and I are exploring this idea by comparing plants grown from the wild populations that were used to establish cultivated populations and plants grown from commercial seed after the plants have been under cultivation for multiple generations at Native Ideals Farm. In addition, an undergraduate and I, Paige Fliehr, have distributed an international survey to native plant producers to determine key decisions they make that might affect genetic diversity in restoration materials.
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