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Common lilac is an important flowering shrub that accounts for ≈$20 million of sales in the U.S. nursery industry. Cultivar improvement in common lilac has been ongoing for centuries, yet little research has focused on shortening the multiple-year juvenility period for lilacs and the subsequent time required between breeding cycles. The practice of direct-sowing of immature “green” seed has been shown to reduce juvenility in some woody plants, but it has not been reported for common lilac. This study investigated the effects of seed maturity [weeks after pollination (WAP)], pregermination seed treatment (direct-sown vs. cold-stratified), and postgermination seedling chilling on the germination percentage, subsequent plant growth, and time to flower on lilac seedlings. All seedlings were derived from the female parent ‘Ludwig Spaeth’ and the male parent ‘Angel White’. Seeds harvested at 15 and 20 WAP resulted in 58% (sd ± 9.9%) and 80% (sd ± 9.0%) germination, respectively, which were similar to that of dry seed collected at 20 WAP with stratification (62% ± 4.2%). Seedlings from the green seed collected at 15 and 20 WAP were also approximately three-times taller than those of dry seed groups DS1, DS2, and DS3 after the first growing season. Over the next two growing seasons, there were no differences in seedling height across all treatments. Flowering occurred at the beginning of the fourth season and without differences among treatments. These results indicate that the collection and direct sowing of immature, green seed can be used to successfully grow lilac seedlings, but that they do not reduce the juvenility period. However, this method can provide more vegetative growth in year one to observe early vegetative traits such as leaf color, and it can provide more material for DNA extraction to support molecular research.

Conventional wisdom regarding potato breeding indicates that a strong triploid block prevents the development of viable triploid seeds from crosses between tetraploid and diploid clones. However, in a recent set of crosses between elite tetraploid potatoes and an improved diploid hybrid population derived from group Stenotomum and group Phureja, 61.5% of the resulting clones were found to be triploid. If clones derived from one diploid parent suspected of producing a high frequency of unreduced gametes were excluded, then the frequency of triploid clones increased to 74.4%. Tubers of these triploids are generally intermediates of the two parental groups. Our findings indicate the possibility of using triploid potatoes in potato variety development programs and in genetic and genomic studies.

Genetic resources are the foundation of American agriculture’s ongoing success—the diversity, security, health, and genetic integrity of these resources must be safeguarded. However, in contrast to other crops, protecting, managing, and using collections of woody landscape plant genetic resources present significant challenges. These include conservation of at-risk populations that have high genetic diversity, evaluation of taxa with an unknown potential to invade, and management of large specimens that have long generation times and often recalcitrant or difficult-to-store seeds. The wide diversity of taxa and the limited number of specialist curators and scholars present further challenges. Thus, effective collection, preservation, evaluation, and distribution of woody landscape plant germplasm require substantial and specialized resources. The most fundamental challenge is simple: too many built landscapes have low taxonomic diversity and are often dominated by a single taxon, or monoculture. In turn, these taxonomically and genetically depauperate landscapes are vulnerable to a host of biotic and abiotic threats and are less likely to provide ecosystem and societal services for which they were designed. To develop more resilient landscapes, there is an urgent need to expand taxonomic diversity, which requires the horticultural community to effectively acquire, curate, evaluate, distribute, and use diverse woody landscape plant genetic resources. The role of the US Department of Agriculture-Agricultural Research Service (USDA-ARS) National Plant Germplasm System (NPGS) Woody Landscape Plant Crop Germplasm Committee (WLPCGC) is to identify vulnerabilities and threats that compromise WLP crops in the United States and make recommendations for prioritization of germplasm acquisition, evaluation, research, and management priorities through regular interaction with stakeholders. Due to the breadth of genera and shifting plant genetic resource needs of the nursery industry, it is impractical to list specific threatened or priority genera in a broadly applicable crop vulnerability statement. Instead, the WLPCGC has identified themes of threats and vulnerabilities providing a foundation upon which to support prioritization as threats to specific genera emerge.