Male sterility is useful for plant breeders to cross-pollinate between plants, especially plants with many small flowers. Cytoplasmic male sterility (CMS) is a way of managing male sterility to get populations of 100% male sterile plants to use as females in plant crossing. In many crops especially sunflowers, and sorghum, most of the cultivars are F1 hybrids made with CMS to benefit from hybrid vigor (heterosis) and thereby improve performance over open pollinated cultivars (Kim and Zhang, 2018). CMS may someday be used to produce improved seeds for amaranths as is already done with those crops (Peters and Jain, 1987; Brenner, 2020). We in the United States National Plant Germplasm System are assembling useful germplasm and information for crop improvement including CMS amaranths (GRIN, 2020a).

Grain amaranth (Amaranthus spp.) seed stocks are customarily from self-pollinating plants that open pollinate and are not F₁ hybrids. However, cytoplasmic male sterility (CMS) traits are available for hybrid seed production. DB 199313 (Reg. No. GS-10, PI 686465) grain amaranth (A. hypochondriacus L.) is the first publicly available CMS line in Amaranthus. It is an F₁ hybrid from a cross between male sterile plants of DB 921 (PI 568125) and male fertile PI 568179. Fertility can be restored by crossing DB 199313 with K432 (PI 538323). DB 199313 is adapted for seed production in Ames, IA, from direct seeding in the field, but it has not been selected for competitive agronomic performance. It provides a new publicly available genetic resource for improved grain amaranth crossing.

The North Central Regional Plant Introduction Station maintains more than 300 accessions of Echinochloa representing 15 species from a diverse cross-section of nations and growing conditions from around the world. With such a diverse collection, no single germination-testing protocol was adequate for accurately assessing their viability. By manipulating light conditions, we determined that some accessions were light-requiring and others were dark-requiring. However, no pattern was found for this response based on taxonomy or improvement status. Most accessions tested showed optimal germination when tests were conducted between 25 to 30°C, but both positive and negative photoblastic responses were sometimes expressed, even at lower temperatures. A sequential treatment of darkness followed by light revealed that skotodormancy (dormancy caused by darkness) was being induced in light-requiring seeds. Similarly, a sequential treatment with light followed by darkness revealed that photodormancy (dormancy caused by light) was being induced in dark-requiring seeds. Thus, without prior knowledge of the light requirements of a particular accession, we conclude that a side-by-side germination test where two replicates receive periodic light (12 hours at 30°C / 12 hours dark at 20°C) and the other two are tested in darkness (12 hours at 30°C / 12 hours at 20°C) is best for Echinochloa. This approach is recommended for germplasm centers, seed-testing laboratories, and others working with genetically and geographically diverse Echinochloa seed lots.

In volume 8 of this newsletter, Reitsma and Widrlechner {1998) reported on the status of Daucus and Apiaceae germplasm at the USDA-ARS North Central Regional Plant Introduction Station {NCRPIS), in Ames, Iowa. The NCRPIS is one of the primary active sites in the U.S. National Plant Germplasm System {NPGS), cons¢rving diverse collections of crop plants and their wild and weedy relatives and making them available for research and educational purposes at no cost to the user. Information about all NPGS collections can be obtained through the Germplasm Resources Information Network (GRIN) database, which can be searched via the Internet at http://www.ars-grin.gov/npgs.

In 1999, Philipp Simon (USDA-ARS, Madison, WI), along with colleagues in Poland, Greece, Syria, and Turkey, organized and conducted an exploration through financial support provided by the USDA-ARS Plant Exchange Office {Williams, 2005). That exploration was designed to collect landrace and wild germplasm of Daucus and other Apiaceae from the eastern Mediterranean, a region with considerable umbel diversity. The incorporation of collections made by Simon and his colleagues during the summer of 1999 into the NPGS has made much of the information presented by Reitsma and Widrlechner {1998) obsolete. In this report, we wish to inform umbel researchers about our success in confirming the identity of these new collections, regenerating them, and making them available for research and education.

Objective

To provide a short non‐technical assessment of the state of United States’ proso millet (Panicum miliaceum) crop vulnerability, issues and evolving needs.

A new method is demonstrated for using concentrated oxygen (O₂ gas) to release seed dormancy. Concentrated O₂ gas in air is known to release seed dormancy in some seeds, including some foxtail (Setaria) species. New medical equipment makes O₂ gas easier to work with than before, so laboratories working with dormant seeds can now use concentrated O₂ gas as a seed treatment on a production basis. Use of medical O₂ gas concentrators is simpler and safer than using O₂ gas supplied by pressurized gas cylinders. Suitable medical O₂ gas concentrators in new or used condition are readily available, operate on standard electrical current, and deliver O₂ gas with low-pressure tubes and fittings. Resealable plastic bags are inflated with concentrated O₂ gas and then sealed as seed treatment chambers. This use of concentrated O₂ gas is confirmed to significantly increase the germination of dormant seeds of giant foxtail (Setaria faberi Herrm) and plains bristlegrass (S. macrostachya Kunth).

We are acquiring the wild relatives of cultivated spinach as part of our investment in crop germplasm. Some of these relatives are native in the United States, and thus should be readily accessible for collecting. We intend to aid research by conserving and distributing seeds of these plants. Three genera of North American spinach relatives are briefly described below. The germplasm should be useful to study phylogenetic relationships, the host ranges of pathogens and pests, stress tolerance, and many other topics.

The wild-growing relatives of the grain crops are useful for long-term worldwide crop improvement research. There are neglected examples that should be accessioned as living seeds in gene banks. Some of the grain crops, amaranth, barnyard millet, proso millet, quinoa, and foxtail millet, have understudied unique and potentially useful crop wild relatives in North America. Other grain crops, barley, buckwheat, and oats, have fewer relatives in North America that are mostly weeds from other continents with more diverse crop wild relatives. The expanding abilities of genomic science are a reason to accession the wild species since there are improved ways to study evolution within genera and make use of wide gene pools. Rare wild species, especially quinoa relatives in North American, should be acquired by gene banks in cooperation with biologists that already study and conserve at-risk plant populations. Many of the grain crop wild relatives are weeds that have evolved herbicide resistance that could be used in breeding new herbicide-resistant cultivars, so well-documented examples should be accessioned and also vouchered in gene banks.

A recently established method for the germination of Echinochloa seeds recognised and accounted for variation in responses to light and darkness. This method used parallel light and dark tests and was successful in promoting germination in most seed lots. However, some samples exhibited deeper dormancy and were not fully responsive to either test. In the present study, we employed warm pretreatments where seeds were exposed to dilute aqueous ethanol solutions to attempt to break their dormancy. Based on tests of five Echinochloa accessions, we propose a new, follow-up protocol that can be used on samples unresponsive to the established method. The additional step involves a 3-day dark pretreatment at 35-37°C, imbibing the seeds in ∼0.25M ethanol (aq). After this pretreatment, the seeds should be germinated for 14 days at 20/30°C (16 hours/ 8 hours) with half held in darkness and the other half exposed to an 8-hour light cycle.

Coriander seeds are susceptible to infestation by chalcid wasps which often render the seeds inviable. Control of chalcids in seeds is a prerequisite for supplying coriander germplasm to requestors throughout the world. Levels of chalcid infestation in coriander seed samples produced at the North Central Regional Plant Introduction Station, in Ames, IA, mandated the need to develop an effective control strategy without harming the seeds. Storing the seeds above liquid nitrogen for 16 hours proved effective in killing chalcids at all life stages without reducing seed germination. Results were based on germination tests, seed dissection, chalcid emergence, and digital x-ray images.