Identification of Sterile, Noninvasive Cultivars of Japanese Spirea

Abstract

<jats:p>Japanese spirea (<jats:italic>Spiraea japonica</jats:italic> L. f.), a popular landscape shrub, has shown the potential to become an invasive weed in both North America and Europe. Twenty commonly available <jats:italic>S. japonica</jats:italic> cultivars were evaluated for fertility using pollen and seed germination. Clones were grown in a randomized, replicated field plot, and additional seed samples were obtained from commercial nurseries and hand-pollinations in the greenhouse. Three sterile cultivars were identified: ‘Crispa’, ‘Dart's Red’, and ‘Neon Flash’. These cultivars demonstrated poor anther dehiscence and very low mean pollen germination, 2.7%, 3.0%, and 1.3%, respectively, which often produced abnormal pollen tubes. None of these three cultivars produced viable seed in the field plot, at commercial nurseries, or when hand-pollinated in the greenhouse, whereas seed germination from fertile clones ranged from 91.5% to 100%. The other 17 cultivars tested, which should be treated as entirely fertile for the purposes of invasive plant management, were ‘Albiflora’, ‘Anthony Waterer’, ‘Candlelight’, ‘Dakota Goldcharm’, var. alpina ‘Daphne’, ‘Flaming Mound’, ‘Flowering Choice’, ‘Froebelii’, ‘Golden Princess’, ‘Goldflame’, ‘Goldmound’, ‘Gumball’, ‘Lemon Princess’, ‘Little Princess’, ‘Magic Carpet’, ‘Norman’, and ‘Shibori’. Measurements of DNA content indicated that all tested clones are diploid; therefore, the observed sterility was not related to polyploidy. The identification of these three sterile cultivars can help reduce the use of fertile varieties in areas where Japanese spirea has shown the potential to become invasive.</jats:p>

Hitting the right target: taxonomic challenges for, and of, plant invasions

“…However, we need to understand all aspects of invasions, and the biological species concept is inadequate for resolution of some key facets of invasion ecology such as the crucial details of subspecific differences, cultivars and hybrids. For example, horticulturalists and regulators need tools to separate non-invasive from invasive cultivars ( Wilson and Hoch 2009 ). At a minimum, legal frameworks should support identification and monitoring of alien species below the species level as part of a broader requirement for identifying and monitoring components of biological diversity ( Shine et al 2000 ).…”

Identifying safe cultivars of invasive plants: six questions for risk assessment, management, and communication

“…Pollen germination experiments are conducted by allowing the pollen to germinate in a pollen germination media. The emergence of a pollen tube from the pollen grain is then recorded as evidence of pollen viability (Wilson and Hoch 2009).…”

“…Cytogenetic tests: Polyploidy levels can be detected by chromosomal staining during cell division or by using more recent techniques, such as flow cytometry (Wilson and Hoch 2009). Individuals with odd ploidy or an abnormal cell division process are likely to be sterile or less fecund.…”

Türkiye Florası İçin Yeni Yabancı Bir Kayıt: Spiraea japonica (Rosaceae)

“…These taxa have negative effects on natural ecosystems in a variety of ways. Reduction of diversity through the displacement of native species, reducing soil stability and water quality, and altering fire regimes and nutrient cycling are the main ones (Raizada et al, 2008;Wilson & Hoch, 2009).…”