Bruce Coulman

Expression of anthocyanins and proanthocyanidins after transformation of alfalfa with maize Lc.

Three anthocyanin regulatory genes of maize (Zea mays; Lc, B-Peru, and C1) were introduced into alfalfa (Medicago sativa) in a strategy designed to stimulate the flavonoid pathway and alter the composition of flavonoids produced in forage. Lc constructs included a full-length gene and a gene with a shortened 5′-untranslated region. Lc RNA was strongly expressed in Lc transgenic alfalfa foliage, but accumulation of red-purple anthocyanin was observed only under conditions of high light intensity or low temperature. These stress conditions induced chalcone synthase and flavanone 3-hydroxylase expression in Lc transgenic alfalfa foliage compared with non-transformed plants. Genotypes containing the Lc transgene construct with a full-length 5′-untranslated region responded more quickly to stress conditions and with a more extreme phenotype. High-performance liquid chromatography analysis of field-grown tissue indicated that flavone content was reduced in forage of the Lc transgenic plants. Leucocyanidin reductase, the enzyme that controls entry of metabolites into the proanthocyanidin pathway, was activated both in foliage and in developing seeds of the Lc transgenic alfalfa genotypes. Proanthocyanidin polymer was accumulated in the forage, but (+)-catechin monomers were not detected. B-Peru transgenic and C1 transgenic populations displayed no visible phenotypic changes, although these transgenes were expressed at detectable levels. These results support the emerging picture of Lc transgene-specific patterns of expression in different recipient species. These results demonstrate that proanthocyanidin biosynthesis can be stimulated in alfalfa forage using an myc-like transgene, and they pave the way for the development of high quality, bloat-safe cultivars with ruminal protein bypass.

Using thermal time models to predict seedling emergence of orchardgrass ( Dactylis glomerata L.) under alternating temperature regimes

The effects of alternating temperatures on seed dormancy changes, germination and seedling emergence were investigated in ‘Arctic’ and ‘Lineta’ orchardgrass ( Dactylis glomerata L.). Thermal time models were successfully developed for 0, 5, 10 and 15°C temperature amplitudes, using 28 constant and alternating temperature regimes. These models were then modified by linking seed germination in Petri dishes and seedling emergence in soil. A field experiment was conducted with four seeding dates over 2 years to validate the modified thermal time models. Temperature regimes with a 5–15°C amplitude enhanced seed germination percentages of orchardgrass, indicating that the conditional dormancy was released by these temperature regimes. Base temperatures decreased with increasing temperature amplitude. Seeds germinated more rapidly under alternating temperatures than under constant temperatures. The dual effects of temperature for dormancy breaking and germination were accounted for by thermal time models based on alternating temperature regimes, which accurately predicted the timing and percentage of ‘Arctic’ and ‘Lineta’ orchardgrass seedlings emerging in the field ( R 2 ≥0.88).

Nutrient composition and degradation profiles of anthocyanidin-accumulating Lc-alfalfa populations.

Alfalfa (Medicago sativa L.) is one of the most used forages in the world but suffers the disadvantage of having poor protein utilization by the animal. The poor protein utilization is the result of excessive ruminal protein degradation, which might be reduced by the protein precipitating capacity of anthocyanidin (AC) and condensed tannins (CT). The objective of this study was to determine the effects of the Lc-transgene on survival, anthocyanidin, condensed tannin and chemical profiles in crossed populations of western Canadian-adapted Lc-alfalfa. These were compared with their non-transgenic (NT) parental varieties, Rangelander, Rambler, and Beaver. Lc-alfalfa forage accumulated enhanced amounts of anthocyanidin, with an average concentration of 197.4 µg g-1 DM, while condensed tannins were not detected. Both of these metabolites were absent in the NT parental varieties. Lc-alfalfa had a lower (24.8 vs. 27.3% DM; P < 0.02) crude protein (CP) and higher (58.3 vs. 55.5% DM; P < 0.01) carbohydrate (CHO) c...

Knowles hybrid bromegrass

Knowles was selected from hybrid populations resulting from crosses between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass (Bromus inermis Leyss.). It has a unique array of plant characteristics, some similar to meadow bromegrass, and others more similar to smooth bromegrass. In regional trials, Knowles produced hay yields greater than meadow brome, but lower than smooth bromegrass. It was superior to smooth bromegrass in regrowth after cutting. For steer grazing performance, Knowles was equal or superior to its parental species, perhaps due to its lower fiber concentrations at vegetative growth stages. Key words: Hybrid bromegrass, Bromus riparius × Bromus inermis, cultivar description

Characterization of meadow × smooth bromegrass hybrid populations using morphological characteristics

Three hybrid populations between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass (Bromus inermis Leyss.) have been developed using recurrent selection for vigor, uniformity of growth and floret fertility. The objective of this study was to use morphological characters to characterize the three hybrid populations (S-9197, S-9073, and S-9183) and the two parental species. Tiller heights did not differ among the hybrids and the parental species. Leaf-to-stem ratio of the hybrids was intermediate to that of the parents. Tiller density, panicle density and dry matter yield of the hybrids were more similar to those of smooth bromegrass. Leaf pubescence densities of the hybrids were higher than the parental species, but pubescence lengths closely resembled meadow bromegrass. Leaf area index (LAI) of the hybrids was lower than smooth bromegrass, and resembled meadow bromegrass. Lowest brown leaf spot ratings were observed in meadow bromegrass, while the hybrids were similar to smooth bromegrass. I...

Genetic Systems for Condensed Tannin Biotechnology

Condensed tannins (proanthocyanidins) are plant phenolic polymers with protein-binding, carbohydrate-binding, and antioxidant properties. Dietary condensed tannins deter some insects from feeding on crops, disrupt insect digestion and growth,1 and deter larger browsing and foraging animals.2 As well, the very high levels of condensed tannins found in tropical plant species likely protect these plants from the damaging effects of strong sunlight. Patterns of expression of condensed tannins vary widely within tissues and among plant species, but could be substantially improved in some plant species to suit agricultural and industrial applications.

Fermentation, degradation and microbial nitrogen partitioning for three forage colour phenotypes within anthocyanidin‐accumulating Lc‐alfalfa progeny

BACKGROUND Alfalfa has the disadvantage of having a rapid initial rate of protein degradation, which results in pasture bloat, low efficiency of protein utilisation and excessive nitrogen (N) pollution into the environment for cattle. Introducing a gene that stimulates the accumulation of monomeric/polymeric anthocyanidins might reduce the ruminal protein degradation rate (by fixing protein and/or direct interaction with microbes) and additionally reduce methane emission. The objectives of this study were to evaluate in vitro fermentation, degradation and microbial N partitioning of three forage colour phenotypes (green, light purple-green (LPG) and purple-green (PG)) within newly developed Lc-progeny and to compare them with those of parental green non-transgenic (NT) alfalfa. RESULTS PG-Lc accumulated more anthocyanidin compared with Green-Lc (P < 0.05), with LPG-Lc intermediate. Volatile fatty acids and potentially degradable dry matter (DM) and N were similar among the four phenotypes. Gas, methane and ammonia accumulation rates were slower for the two purple-Lc phenotypes compared with NT-alfalfa (P < 0.05), while Green-Lc was intermediate. Effective degradable DM and N were lower in the three Lc-phenotypes (P < 0.05) compared with NT-alfalfa. Anthocyanidin concentration was negatively correlated (P < 0.05) with gas and methane production rates and effective degradability of DM and N. CONCLUSION The Lc-alfalfa phenotypes accumulated anthocyanidin. Fermentation and degradation parameters indicated a reduced rate of fermentation and effective degradability for both purple anthocyanidin-accumulating Lc-alfalfa phenotypes compared with NT-alfalfa.

Success hybrid bromegrass

Success hybrid bromegrass was selected from populations produced by backcrossing smooth bromegrass (Bromus inermis Leyss.) with hybrid populations resulting from crosses between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass. Success has a unique array of plant characteristics, some similar to meadow bromegrass, and others more similar to smooth bromegrass; overall, it more closely resembles smooth brome. In regional trials in the prairie provinces of western Canada, Success produced forage yields greater than meadow brome, but lower than smooth bromegrass. In the drier brown soil zone of the prairie provinces, Success was superior to both meadow and smooth bromegrass in forage yield. It was superior to smooth bromegrass in regrowth after cutting and had lower concentrations of acid-detergent fiber than meadow bromegrass. Key words: Hybrid bromegrass, Bromus riparius × Bromus inermis, cultivar description

Sainfoin (Onobrychis viciifolia Scop.): Renewed interest as a forage legume for western Canada

Abstract: Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume that has received renewed interest in western Canada because of its desirable forage characteristics. The objective of this review is to summarize previous studies on the agronomy, forage yield, nutritive value, seed characteristics, and diseases and pests of sainfoin. In addition, the review also focuses on the genetic diversity and registered cultivars of sainfoin and their potential use in temperate grasslands. Past studies have reported that sainfoin has a high nutritive value, and high voluntary intake and palatability to grazing animals. In western Canada, dry matter (DM) yield of sainfoin is 80%–95% that of alfalfa (Medicago sativa L.). Unlike other legumes such as alfalfa, sainfoin does not cause bloat in grazing animals due to the presence of condensed tannins. Sainfoin is suitable for monoculture or binary mixtures with either grasses or alfalfa. Genetic diversity studies revealed that sainfoin germplasm generally has high variation within populations. Genetic variation among plants provides an opportunity to develop improved cultivars with desirable characteristics. However, compared with the other forage legumes, sainfoin is still an underdeveloped forage crop with few cultivars being available in western Canada. New sainfoin cultivars with high DM yield and persistence under regional growing conditions are required.

Goliath crested wheatgrass

Goliath is a colchicine-induced tetraploid cultivar of crested wheatgrass [Agropyron cristatum (L.) Gaertner]. Relative to other cultivars of crested wheatgrass, Goliath is taller, produces fewer, heavier tillers, and has greater seed weight. It produced higher seed yields than other cultivars and had a higher mean forage dry matter yield than the check cultivar in regional trials conducted in the three Canadian prairie provinces. Key words: Crested wheatgrass, Agropyron cristatum (L.) Gaertner, colchicine-induced tetraploid, cultivar description