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- Author or Editor: Keenan L. Amundsen x
Buffalograss is a warm-season, dioecious grass species yielding burs, which are routinely used for field plantings. The pistillate plants bear the burs containing 1–5 caryopses. Isolated caryopses readily germinate, but caryopses contained within burs exhibit strong dormancy, suggesting that burs inhibit germination. Priming burs with low concentrations of potassium nitrate (KNO3) is used as an industry standard to improve germination. Seed dormancy and germination in many species are strongly influenced by endogenous hormone levels, principally abscisic acid (ABA) and gibberellic acid (GA). It follows that buffalograss seed dormancy might be induced or overcome by altering the ratio of ABA to GA. The objectives of this research were 1) to contrast the effects of priming with KNO3 or water on bur germination, 2) to study how these treatments affected hormone profiles, specifically the ABA/GA ratios in the burs, and 3) to quantify treatment effects on the water permeability of the burs. Hormone profiles were analyzed following four postharvest seed-soaking treatments (24-hour 0.05 m KNO3, 24-hour H2O, 48-hour 0.05 m KNO3, and 48-hour H2O). Water infiltration tests on nontreated, 24-hour H2O-treated, and 24-hour 0.05 m KNO3-treated seeds were also conducted. Inconclusive hormone profiling results did not support the hypothesis that KNO3 postharvest treatment raises GA levels to encourage germination. Instead, our data support changes in seed morphology following KNO3 postharvest seed treatments which alter water permeability of the seedcoat leading to increased germination.
Little information exists on dormant seeding of buffalograss [Buchloe dactyloides (Nutt.) Engelm.]. The objectives of these two studies were to determine how seeding rate affects establishment of ‘Sundancer’ buffalograss when dormant and spring-seeded, and to evaluate if cultivar or seeding date affects establishment of ‘Cody’, ‘Bowie’, or ‘Sundancer’ buffalograss when seeded at various dates during the winter and spring. In the first study, ‘Sundancer’ buffalograss was dormant seeded at 146, 244, or 293 kg·ha−1 in late November in 2012 and 2013 or spring-seeded in early May in 2013 and 2014. In the second study, ‘Sundancer’, ‘Bowie’, or ‘Cody’ was seeded at 146 kg·ha−1 in late November in 2013 and 2014, late January, March, and May in 2014 and 2015. Dormant seeding of buffalograss resulted in >80% cover by the following August in all studies. Increasing seeding rate had no effect on establishment of ‘Sundancer’, regardless of seeding date. Furthermore, there was no difference in turf cover by August following seeding of ‘Sundancer’, ‘Bowie’, or ‘Cody’ at 146 kg·ha−1 in late November, January, March, or May. Our results suggest that ‘Sundancer’, ‘Bowie’, or ‘Cody’ can be successfully dormant seeded at 146 kg·ha−1 from late November through late March, which allows establishment before the following winter.
Hybridization and selection has been one of the methods used to generate turfgrass cultivars in buffalograss improvement. Three half-sib populations were developed by crossing three buffalograss female genotypes, NE 3296, NE 2768, and NE 2769, with NE 2871, a male genotype, to 1) investigate the pattern of genetic variability generated for turfgrass characteristics through hybridization; 2) assess the effect of parental change on the level of genetic variability generated in a buffalograss diploid population; and 3) predict the performance of a progeny generated from two heterozygous parents for turfgrass performance. The four parents and 20 random F1 progeny selected from each population were established in 2006 at the John Seaton Anderson Turfgrass Research Facility located near Mead, NE. A randomized complete block design (RCBD) was used with the progeny nested in the crosses. A visual rating scale of 1–9 was used to evaluate the population. Mean population lateral spread, genetic color, density, and turfgrass quality from early summer to fall ranged from 3.5 to 4.5, 7.1 to 7.9, 6.9 to 8.1, and 5.2 and 6.8, respectively. There were significant differences among the crosses and the parents for all the traits studied except quality in June and August. The progeny nested within crosses differed for turfgrass genetic color and quality. Best linear unbiased prediction (BLUP) indicated a high improvement potential for turfgrass lateral spread and spring density in NE 2768 × NE 2871 and for turfgrass genetic color in NE 3296 × NE 2871. From these findings, it can be concluded that hybridization breeding is a worthwhile approach for generating and identifying transgressive segregants for specific buffalograss traits.