Breeding of Nonflowering Orchardgrass, Dactylis glomerata L.¹

Abstract

Among nearly 4,000 spaced plants in a breeding nursery of orchardgrass, Dactylis glomerata, 9 remained nonflowering near University Park, Pa., during the growing seasons of 1959, 1960, and 1961. Experiments with floral inductive treatments of 8, 10, 13, and 16 weeks of short days at 10 C or below subdivided selected clones from this nursery into three groups. Three 4‐clone synthetics with different cold inductive floral requirements were formulated. First‐generation (Syn 1) seed produced in 1963 at Prosser, Wash., of Syn A, Syn B, and Syn C, averaged, respectively, 50 g, 21 g, and 32 g per clone. The Syn 1 generation was compared with ‘Pennlate’ in solid‐seeded field plots for production of panicles and forage in the Northeast. In June 1965 Pennlate, Syn A, Syn B, and Syn C produced, respectively, 12.6, 13.1, 4.1, and 1.7 panicles per square foot in Pennsylvania and 37.2, 4.3, 1.8, and 0.6 in Vermont These data indicated a genetic basis for the nonflowering characteristic.

Sparse‐Flowering Orchardgrass is Stable Across Temperate North America

“…The origin of the germplasm is largely unknown, with pedigree information only sufficient to trace the parental genotypes back to pastures in central Pennsylvania (Hovin et al, 1966). It is entirely conceivable that the original germplasm base, or the parental clones selected from these fields, were inherently low in forage yield potential, but we can only speculate on this point.…”

“…Sparse-flowering orchardgrass plants were discovered in pastures in Pennsylvania in the 1960s and used to develop breeding populations capable of seed production in milder climates (Hovin et al, 1966). Because orchardgrass flowering is induced by prolonged exposure to short days of autumn, longer winters or earlier onset of cold temperatures will suppress flowering (Heide, 1987).…”

Feasibility of Seed Production from Nonflowering Orchardgrass

“…The germplasm for this experiment derives from two sparsefl owering orchardgrass populations discovered and initially characterized in the 1960s at State College, PA (Hovin et al, 1966). The two populations were renamed WO-SF-B and WO-SF-C by Casler et al (2004).…”

“…Although hundreds of cultivars have been developed within this species, seed markets are generally dominated by early fl owering cultivars, largely because they tend to have the greatest seed production, reducing the cost of seed to forage producers (Casler et al, 1997(Casler et al, , 2000. Hovin et al (1966) developed two sparse-fl owering orchardgrass populations that had normal panicle and seed production in eastern Washington, but severely reduced panicle production in Pennsylvania and Vermont (Berg et al, 1981). Although the concept of using nonfl owering or sparse-fl owering cultivars to avoid this problem has been known for many years, there has been little progress toward developing cultivars that possess this trait in a pasture setting, but also are capable of economically viable seed production.…”

“…The four locations were grouped into two categories based on the fl owering responses of the four sparse-fl owering populations (Table 4). Parlier was an unsuitable location for seed production of the sparse-fl owering populations, most likely due to warmer temperatures during autumn which would inhibit vernalization response and fl oral induction (Hovin et al, 1966;Ikegawa et al, 1982), shorter photoperiod which would inhibit fl oral initiation (Broué, 1973;Gardner and Loomis, 1953), and warmer temperatures during spring and summer which would probably inhibit seed set and fi ll (Ikegawa et al, 1982;Broué and Nicholls, 1973). Parlier was an unsuitable location for seed production of the sparse-fl owering populations, most likely due to warmer temperatures during autumn which would inhibit vernalization response and fl oral induction (Hovin et al, 1966;Ikegawa et al, 1982), shorter photoperiod which would inhibit fl oral initiation (Broué, 1973;Gardner and Loomis, 1953), and warmer temperatures during spring and summer which would probably inhibit seed set and fi ll (Ikegawa et al, 1982;Broué and Nicholls, 1973).…”