Variability and Breeding Behavior in Big Bluestem Populations from Eastern South Dakota

Three spaced-plant big bluestem (Andropogon gerardii Vit.) nurseries at Brookings, South Dakota were analyzed for their genetic variability and agronomic potential. Unselected native collections, the 1972 nursery, was comprised of 34 strains each representing a site collection from the eastern edge of South Dakota. The first cycle recurrent selection nursery, established in 1977, was comprised of progeny of 19 plants from the 1972 nursery that were exceptional seed producers in the drought year 1976. The second cycle recurrent selection nursery, established in 1976, was comprised of progeny of 33 agronomically desirable plants from open-pollinated nurseries established from difference southeastern South Dakota collections. These collections were from selected plants in relict colonies in southeastern South Dakota. The objectives of this study were to describe the variation in the populations studied, to estimate heritabilities of the agronomically desirable characteristic and to determine the most efficient breeding methods to produce a superior variety. Higher significant differences for seed yield, vigor, leafiness and plant height were found among strains in the 1972 nursery and among half-sib families in the 1976 and 1977 nurseries. Highly significant differences for seed weight were found among families in the 1976 and 1977 nurseries. Broad sense heritability estimates for strains were high plant height, heading date and pollination date in the 1972 nursery. Narrow sense heritability estimates based on one year’s data were extremely high for seed weight, plant height, vigor, leafiness, number of flowering culms and seed yield in the 1977 nursery. Positive assortative mating (like to like) must have been responsible for inflationary effects on the heritability estimates. Narrow sense heritability estimates based on two years’ data were moderately high for vigor, leafiness and plant height in the 1976 nursery. Estimates based on one year’s data were moderately high for seed yield and fertility index and very high for seed weight. Phenotypic and genetic correlations between agronomic characters in the 1976 and 1977 nurseries were generally positive, indicating that simultaneous multitrait selection for forage and seed characters would be profitable. Multiple regression and path coefficient analysis of seed yield components in the 1977 nursery indicated that number of flowering culms, size and/or number of racemes per culm and fertility index all contributed directly to seed yield. Number of flowering was the most important while size and/or number of racemes per culm and fertility index were both considerably more important than seed weight in determining seed yield. A composite made from open-pollinated seed of plants with heavy seeds (means 100 seed weight = .26g) from the 1976 nursery produced significantly taller seedlings than a composite comprised of plants selected for forage and seed yield (mean 100 seed weight = .20g) from the same nursery. A seed weight is highly heritable, mass selection for heavy seed should enhance seedling vigor. Mass selection should be extremely effective for seed weight and plant height and moderately effective for seed yield, vigor, leafiness, fertility index and number of flowering culms. More precision in selection, however, for these characters would be possible based on progeny test data. No sizable negative genetic correlations between characters were observed, consequently simultaneous multitrait selection should be effective

Life History Studies, Host Records, and Morphological Description of Genitalia of Eurytoma tylodermatis Ashm. (Hymenoptera : Eurytomidae) from South Dakota

Eurytoma tylodermatis Ashm. was found to be parasitic on Acanthoscelides perforatus (Horn) in seed pods of Canada milk- vetch {Astragalus canadensis L.). Observations on larval behavior and frequency of parasitism are discussed. Male and female genitalia of E. tylodermatis are illustrated

A new Bruchophagus from Glycyrrhiza lepidota pursh in the Northern Great Plains (Hymenoptera : chalcidoidea : eurytomidae)

A new species, Bruchophagus grisselli McDaniel and Boe, which infests seeds of Glycyrrhiza lepidota Pursh (American licorice), is described and illustrated. It\u27s known from South Dakota and North Dakota in the USA. A field study at 8 sites showed that B. grisselli has a wide distribution throughout the Dakotas

Fates of Ovules in Groundplum Milk-Vetch (Astragalus crassicarpus Nutt.) in South Dakota

Groundplum milk-vetch (Astragalus crassicarpus Nutt.) is a native legume found on gravelly to sandy prairie uplands throughout central North America. The large and fleshy fruits, or pods, of this species were consumed by indigenous people and European settlers, and are cached by rodents. Our previous research on native legumes of the northern Great Plains indicated seed predation by insects, notably bruchid beetles belonging to the genus Acanthoscelides Schilsky, was a dominant factor determining viable seed production in natural and artificial plant assemblages. However, although we have studied the reproductive biology of several species of Astragalus L., none had fleshy pods. Therefore, the objective of this study was to quantify the factors influencing viable seed production in natural populations of GPMV in South Dakota. Mature pods were collected from two natural populations on the South Dakota State University Oak Lake Field Station during July 2000 and from one natural population on the Grand River National Grassland near Lodgepole, SD, in July 2003. Pods were dissected and number of ovules that: 1) produced viable seed, 2) were unfertilized, 3) produced aborted seed, and 4) produced seeds that were predated by larvae of the bruchid beetle Acanthoscelides fraterculus (Horn) (Coleoptera: Chrysomelidae: Bruchinae) were recorded for each of the two valves of individual pods. Our results indicated average seed set, i.e., percent of ovules that produced viable seed not predated, was about 55%, averaged across populations. Unfertilized ovules were 42% of the total. Predation by the bruchid beetle occurred in about 2% of the developed seeds, with aborted seed making up the rest of the ovule total. About 35% of pods infested contained larvae, or adults that were immured within the pod while attempting to exit, presumably due to the thick and leathery layers of the ovary wall. Predispersal seed predation was a relatively minor factor in the reduction of viable seed set in GPMV in South Dakota

Native Grass and Legume Biology and Establishment

https://openprairie.sdstate.edu/oak-lake_presentations/1000/thumbnail.jp

Biomass Production of Monocultures and Mixtures of Cup Plant and Native Grasses on Prime and Marginal Cropland

To date, most candidate systems for producing herbaceous cellulosic biomass have been composed of monocultures of perennial or annual grasses. Ecosystem goods and services provided from these biomass feedstock production systems could be increased dramatically with mixing of one or more forb species that would increase biodiversity and provide habitat for pollinators. Cup plant (Silphium perfoliatum L.) is featured with many desirable characteristics, such as high biomass potential, adaptation to marginal soils, and attractiveness to pollinators, desirable in a dicot species to grow in mixtures with perennial warm-season grasses. The objective of this study was to compare cup plant, switchgrass (Panicum virgatum L.), and prairie cordgrass (Spartina pectinata Link) monocultures to their mixtures for biomass production on prime and poorly drained marginal crop land for two years in both South Dakota and Wisconsin. In Wisconsin, monocultures of prairie cordgrass and cup plant and their mixture produced more biomass (8.1 Mg·ha-1) than the switchgrass monoculture and switchgrass/cup plant mixture (5.3 Mg·ha-1) on both prime and marginal land. While in South Dakota, drought and meristem destruction by the cup plant moth (Eucosma giganteana Riley) caused large reductions in biomass production (1.7 Mg·ha-1) in both years, with the switchgrass/cup plant mixture on marginal land having the highest yield (2.1 Mg·ha-1). Our study showed binary mixtures of cup plant and native warm-season grasses have great potential for increasing biodiversity and other ecosystem goods and services, relative to monocultures, for sustainable biomass feedstock production on poorly drained marginal land in the northcentral USA

Symptoms, Distribution and Abundance of the Stem-Boring Caterpillar, Blastobasis repartella (Dietz), in Switchgrass

A potential pest of switchgrass, Panicum virgatum L., was first detected in South Dakota in 2004, where death of partially emerged leaves was noted in a small proportion of tillers. Similar “dead heart” symptoms were observed in switchgrass in Illinois during 2008 and adults of a stem-boring caterpillar were collected and identified as Blastobasis repartella (Dietz). In 2009, a survey of the central United States was used to estimate the distribution and abundance of this insect. In eight northern states, B. repartella was consistently found in both cultivated plots and natural stands of switchgrass. In four southern states, B. repartella was not detected. However, because symptoms are conspicuous for a short period of time, failure to collect stem-borers on one survey date for each southern location does not necessarily define the limit of distribution for B. repartella. Sampling in four northern states showed the proportion of tillers damaged by B. repartella ranged from 1.0–7.2%. Unlike some caterpillars that feed on native grasses, it appears that the egg-laying behavior of adult moths may preclude the use of prescribed burns as an effective method to suppress this stem-boring caterpillar. As a potential pest of switchgrass planted for biomass production, near-term research needs include refining the geographic distribution of B. repartella, quantifying potential losses of switchgrass biomass, and determining whether switchgrass may be bred for resistance this and other stem-boring insects

Breeding Alfalfa for Semiarid Regions in the Northern Great Plains: History and Additional Genetic Evaluations of Novel Germplasm

Yellow-flowered alfalfa (Medicago sativa subsp. falcata) (also known as sickle medic) has been the cornerstone for breeding alfalfa for dual grazing and hay production in the semiarid regions of the northern Great Plains in the US and Canada. Most, if not all, of the cultivars developed for the northern Great Plains during the 20th century, had parentage tracing back to introductions by Niels Ebbesen Hansen that were obtained from expeditions to Russia, primarily the province of Siberia, on behalf of the United States Department of Agriculture during the early 1900s. The M. falcata genome contains alleles for high levels of drought-tolerance, winter hardiness, and tolerance to grazing, but is generally deficient for commercial seed production traits, such as non-shatter, compared with common alfalfa (M. sativa). A naturalized population, tracing to USDA plant introductions to Perkins County South Dakota by N.E. Hansen in early 1900, and subsequently, facilitated by the determined seed increase and interseeding of a population by a local rancher, Norman ‘Bud’ Smith, has shown highly desirable in situ characteristics for improving rangelands in the northern Great Plains. This includes adequate seed production to build a seed bank in the soil for natural seedling recruitment and population maintenance/expansion and support the production of a commercial seed source. This review documents the seminal events in the development of cultivars to date and describes novel germplasm with potential for new cultivars in the future

Biomass Yield of Switchgrass Cultivars under High- versus Low-Input Conditions

Switchgrass (Panicum virgatum L.) is undergoing development as a biomass crop to support conversion of cellulosic biomass to energy. To avoid the competition of biomass with food or feed crops, most commercialization proposals suggest that switchgrass should be grown exclusively on marginal lands that are not fit for food or feed production. The objective of this study was to investigate the potential for cultivar x environment interactions that would affect the methods and approaches for breeding and evaluating switchgrass cultivars, including both upland and lowland types, for high-input versus low-input types of environments. Biomass yield was measured on 14 cultivars that were present in 28 replicated field experiments representing seven regions, ranging from 75 to 100° W and spanning USDA Hardiness Zones 4 through 7. Region was the most important environmental factor interacting with cultivars, supporting the idea that the north-central and northeastern United States should have independent switchgrass breeding programs. Cultivars interacted with soil phosphorus concentration in New Jersey and with depth of the A and B horizons in New York and showed mild interactions with rate of nitrogen fertilizer at several locations. Cultivar rank correlation coefficients between the two rates of nitrogen fertilization (100 vs. 0 kg N ha−1) ranged from 0.23 to 0.88, suggesting a possible benefit to breeding and selection without applied nitrogen fertilizer