No effect of transgene and strong wild parent effects on seed dormancy in crop-wild hybrids of rice: implications for transgene persistence in wild populations

Seed germination patterns were studied in Echinacea purpurea (L.) Moench grouped by seed source, one group of seven lots from commercially cultivated populations and a second group of nine lots regenerated from ex situ conserved wild populations. Germination tests were conducted in a growth chamber in light (40 μmol·m–2·s–1) or darkness at 25 °C for 20 days after soaking the seeds in water for 10 minutes. Except for two seed lots from wild populations, better germination was observed for commercially cultivated populations in light (90% mean among seed lots, ranging from 82% to 95%) and in darkness (88% mean among seed lots, ranging from 82% to 97%) than for wild populations in light (56% mean among seed lots, ranging from 9% to 92%) or in darkness (37% mean among seed lots, ranging from 4% to 78%). No germination difference was measured between treatments in light and darkness in the commercially cultivated populations, but significant differences were noted for treatments among wild populations. These results suggest that repeated cycles of sowing seeds during cultivation without treatments for dormancy release resulted in reduced seed dormancy in E. purpurea.

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Seed Germination of Intermountain Penstemons as Influenced by Stratification and GA3 Treatments

Journal of Environmental Horticulture ◽

10.24266/0738-2898-9.1.51 ◽

1991 ◽

Vol 9 (1) ◽

pp. 51-56 ◽

Cited By ~ 2

Author(s):

Stanley G. Kitchen ◽

Susan E. Meyer

Keyword(s):

Gibberellic Acid ◽

Seed Dormancy ◽

Practical Method ◽

Considerable Variability ◽

Wild Populations ◽

Numerous Species ◽

Practical Solution ◽

Breaking Dormancy ◽

Selection Of Species ◽

Selection Of

Abstract Propagation of the genus Penstemon for use in landscape horticulture has been handicapped by a lack of understanding of seed dormancy and a practical method for breaking dormancy for numerous species. The extent of dormancy in seeds of 27 wild populations of Penstemon representing 16 Intermountain species was investigated by subjecting seeds to stratification (moist prechilling) of 2 to 16 weeks at 2°C (36°F) and varying concentrations of gibberellic acid (GA3). Germination varied from 0 to 88% for non-treated seeds and from 13 to 100% for seeds treated with 250 ppm GA3. Collections from 10 species required 12 or more weeks of stratification for complete germination. Three species exhibited reduced germination after stratification when compared to the non-chilled control. Gibberellic acid significantly reduced the stratification requirement of seeds for the more dormant species. Concentrations of 150, 250, and 500 ppm GA3 were equally effective in breaking dormancy for most species. The considerable variability in seed dormancy suggests that the most practical solution to penstemon propagation from seed may be the selection of species and ecotypes with minimal dormancy.

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Inheritance of deep seed dormancy and stratification-mediated dormancy alleviation in Amaranthus tuberculatus

Seed Science Research ◽

10.1079/ssr2006250 ◽

2006 ◽

Vol 16 (3) ◽

pp. 193-202 ◽

Cited By ~ 3

Author(s):

Ramon G. Leon ◽

Diane C. Bassham ◽

Micheal D.K. Owen

Keyword(s):

High Temperature ◽

Seed Dormancy ◽

Wild Populations ◽

Weed Species ◽

Narrow Sense Heritability ◽

The Past ◽

Emergence Patterns ◽

Amaranthus Tuberculatus ◽

The Individual ◽

Weed Emergence

Amaranthus tuberculatusis a weed species that has shifted emergence patterns over the past few years, presumably due to changes in seed dormancy in response to selection in agricultural fields. Although it is recognized that the seed dormancy phenotype is greatly affected by the environment, it is also acknowledged that the genotype plays a significant role. However, the importance of the genotype in determining intra-population seed dormancy variability, and the effect on emergence patterns, is not well understood. The objective of the present study was to determine the importance of the genotype on deep dormancy and the stratification-mediated dormancy alleviation inA. tuberculatus. Wild populations differing in seed dormancy were crossed and F2families were generated. These families were used to determine narrow sense heritability of dormancy and stratification-mediated dormancy alleviation at the individual (hi2) and family (hf2) levels.hi2ranged from 0.13 to 0.4 and 0.04 to 0.06 for the dormancy and stratification response, respectively. In the case ofhf2, the values ranged from 0.76 to 0.91 for deep dormancy and from 0.33 to 0.58 for the stratification response. The genetic correlation between these two traits was below 0.075, indicating that different genes control them. High temperature strengthened the dormancy of deeply dormant seeds, making them less sensitive to stratification. However, high temperature promoted the germination of non-deeply dormant seeds. It is proposed that delayed weed emergence can be generated by selecting genes that control stratification response, and not necessarily only the genes that are directly responsible for deep dormancy.

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Optimal germination conditions for monitoring seed viability in wild populations of fescues

Spanish Journal of Agricultural Research ◽

10.5424/sjar/2021193-18025 ◽

2021 ◽

Vol 19 (3) ◽

pp. e0804-e0804

Author(s):

Pablo Vivanco ◽

Keyword(s):

Gibberellic Acid ◽

Seed Dormancy ◽

Seed Viability ◽

Cold Stratification ◽

Wild Populations ◽

Negative Effect ◽

Species Area ◽

Northwestern Spain ◽

Alternating Temperature ◽

Germination Requirements

Aim of study: Germination assays are vital in the management of material preserved in germplasm banks. The rules published by the International Seed Testing Association (ISTA) are generally those followed in such assays. In wild species, seed dormancy and inter-population variability increase the difficulty in estimating seed viability. The aim of the present work was to determine the germination requirements of the seeds from different wild populations of pasture grasses species. Area of study: Northwestern Spain Material and methods: Seeds from eight wild populations of different species of Festuca, all from northwestern Spain, were studied. Germination assays were performed under constant and alternating temperature conditions. Treatments for removing seed dormancy (cold stratification and gibberellic acid application) were also applied. A full parametric time-to event model was used for data analysis. Main results: In general, the optimum environmental temperature for germination was around 15°C for the populations of Festuca group ovina, F. gr. rubra and F. gigantea; temperatures of 20-30ºC had a negative effect. All the examined populations, except that of tall fescue (Lolium arundinaceum), showed non-deep physiological dormancy at suboptimal germination temperatures, but this was breakable by the application of gibberellic acid and by cold stratification. Research highlights: There are clear inter- and intra-specific differences in germination requirements that might be associated with place of origin. The ISTA germination assay recommendations for wild members of fescues may not be the most appropriate.

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