S. N. Acharya

Biochemical monitoring in fenugreek to develop functional food and medicinal plant variants.

Many plants used as functional foods or for medicinal purposes have been criticized for their inconsistent physiological effects. Variation in genotype and environmental conditions under which plants are produced can contribute to this inconsistency in biochemical composition. Fenugreek (Trigonella foenum-graecum L.) is a medicinal plant that not only can lower blood glucose and cholesterol levels in animals, but also can be used as a forage crop for livestock feed. Seed content for the bioactive compounds diosgenin, galactomannan and 4-hydroxyisoleucine was characterized for ten fenugreek genotypes under rainfed and irrigated conditions. High and low seed yielding genotype/environment combinations were identified that possessed distinct biochemical and seed production traits. In general high seed yielding genotype/environment combinations exhibited a more stable biochemical composition and consisted largely of irrigated fenugreek. This research indicates that comprehensive biochemical analysis of plant products would facilitate the development of more reliable produce for use by the functional food/medicinal plant industry.

Ultrastructural Study of Mycoparasitism of Gliocladium Roseum on Botrytis Cinerea

Conidia and germ tubes of Botrytis cinerea were highly susceptible to infection by the mycoparasite Gliocladiurn roseurn, when both organisms were grown as a mixed culture in sterile water containing 8-9×10^(4) pollen grains of alfalfa per ml solution. Scanning electron microscopic studies revealed that infection of conidia and germ tubes occurred through direct penetration by hyphal tips of G. roseum without the formation of appressoria. Transmission electron microscopic studies indicated indentation and rupture of the host cell walls at penetration sites. The parasitized conidia and germ tubes of B. cinerea showed signs of cytoplasmic disintegration and the presence of hyphae of G. roseum.

Biological Control of Blossom Blight of Alfalfa Caused by Botrytis cinerea Under Environmentally Controlled and Field Conditions

Fungal and bacterial antagonists were tested for their inhibition of sporulation of Botrytis cinerea on detached alfalfa florets. Clonostachys rosea, Gliocladium catenulatum, and Trichoderma atroviride were evaluated for protecting young blossoms and pods of alfalfa from infection by B. cinerea in vitro. C. rosea was further tested to control pod rot and seed rot caused by B. cinerea under field conditions. The results showed that four of the tested antagonists, C. rosea, G. catenulatum, T. atroviride, and Trichothecium roseum, could inhibit sporulation by B. cinerea on detached alfalfa florets. Both C. rosea and G. catenulatum were effective in suppression of infection of alfalfa pods by B. cinerea when inoculated on fresh petals of alfalfa at the anthesis stage, and their efficacy was greater than that of Trichoderma atroviride. A significant suppression of B. cinerea by C. rosea and G. catenulatum on pods and seed of alfalfa was observed when they were inoculated on senescent petals at the pod-development stage. Results of a field trial indicated that C. rosea applied to upper parts of alfalfa plants significantly suppressed pod rot and seed rot caused by B. cinerea, and significantly increased seed production of alfalfa in each of 3 years. These studies show that C. rosea has potential as a biocontrol agent for control of alfalfa blossom blight caused by B. cinerea.

Lignin impact on fiber degradation. IV. Enzymatic saccharification and in vitro digestibility of alfalfa and grasses following selective solvent delignification

The response in composition, in vitro dry matter digestibility (IVDDM), and enzymatic saccharification, of alfalfa and various grasses to selective solvent delignification (SSD), as well as the nutritive value of the residual biomass (co-product), was determined. The SSD pretreatment reduced lignin concentrations in grasses but not in alfalfa. Associated effects were increases in concentrations of neutral detergent fiber (NDF) due to losses of cell solubles (all forages) and changes in hemicellulose/cellulose ratio. SSD pretreatment increased IVDDM of the grasses by 11–25%, and this increase was highly correlated with the extent of delignification (r = 0.90). Extent of enzymatic fiber hydrolysis was up to 78%, with reducing sugar production of up to 371 mg/g DM. Differences in forage digestibility caused by stage of maturity were largely overcome by the SSD pretreatment. Fiber composition and IVDDM concentration of the co-products were indicative of low to medium nutritive value. SSD pretreatment seems uniquely capable of enhancing enzymatic saccharification and digestibility of mature, high-yielding grasses, such as giant wildrye.

Importance of Pollen and Senescent Petals in the Suppression of Alfalfa Blossom Blight (Sclerotinia sclerotiorum) by Coniothyrium minitans

The effect of pollen and senescent petals on the suppression of alfalfa (Medicago sativa L.) blossom blight (Sclerotinia sclerotiorum) by the mycoparasite Coniothyrium minitans was investigated. When incubated at 20°C for 39 h, germination of conidia of C. minitans and ascospores of S. sclerotiorum was 99.9 and 98.6%, respectively, in the presence of alfalfa pollen (9×104 pollen grains mL−1), whereas spore germination of both organisms was <0.5% in the absence of pollen (in water). In the presence of a commercial pollen product, Swiss™ pollen granules (mainly bee pollen), germination was 99.6% for C. minitans and 98.3% for S. sclerotiorum when the pollen concentration was 1.0% (w/v). When the pollen concentration was reduced to 0.1% (w/v), germination was reduced to 13.0% for C. minitans and 10.8% for S. sclerotiorum. Tests on detached alfalfa florets showed that the colonization of alfalfa florets by S. sclerotiorum was significantly suppressed by C. minitans in the presence of pollen (1.0% Swiss™ pollen granules), especially when C. minitans was inoculated 1-day before S. sclerotiorum. In vivo inoculation tests revealed that the efficacy of C. minitans in the protection of alfalfa pods from the infection by S. sclerotiorum was affected by the time at which C. minitans was applied. When C. minitans was applied on young blossoms of alfalfa at the anthesis stage, pod infection was 96.6% for the treatment of C. minitans+S. sclerotiorum and 99.6% for the treatment of S. sclerotiorum alone. However, when C. minitans was applied on senescent petals of alfalfa at the pod development stage, pod infection was 8.0% for the treatment of C. minitans+S. sclerotiorum compared to 90.8% for the treatment of S. sclerotiorum alone. These results suggest that timing of the application of C. minitans is critical for the mycoparasite to compete with S. sclerotiorum for the source of nutrients from pollen and senescent petals, and for its control of alfalfa blossom blight caused by S. sclerotiorum.

Quantitative trait loci analysis of economically important traits in Sorghum bicolor × S. sudanense hybrid

Lu, X-p., Yun, J-f., Gao, C-p. and Acharya, S. 2011. Quantitative trait loci analysis of economically important traits in Sorghum bicolor×S. sudanense hybrid. Can. J. Plant Sci. 91: 81-90. Many agronomic traits of Sorghum bicolor×S. sudanense hybrid are quantitatively inherited, and the gene mapping of these traits has important research and practical consequences. In this study, genetic mapping and quantitative trait loci (QTL) analyses were conducted using 248 F2:3 plants of a cross between sorghum 314A (female parent) and Sudan grass 2002GZ-1 (male parent). A total of 178 markers (170 amplified fragment length polymorphism and 8 random amplified polymorphic DNA) were employed to construct a linkage map with 10 linkage groups covering 836 cM of the genome. The two parents expressed polymorphism for 10 agronomic characters (plant height, stem diameter, leaf number, leaf length, leaf width, spike length, tiller number, ratio of stem and leaf weight, fresh plant weight and dry plant weight). When analyzed for possible QTLs a total of 98 QTLs were identified in two test sites, out of which 26 QTLs overlapped in both sites. The average number of QTLs per character was found to be 2.6 and the distributions of these QTLs were found to be uneven across linkage groups. This, and the fact that molecular marker densities were not proportional with QTL frequencies, indicates that the detectable QTLs correlated with the agronomic traits and the genetic map can be useful for improvement in relevant characters in Sorghum bicolor×S. sudanense hybrids.

Identification of Trigonella accessions which lack antimicrobial activity and are suitable for forage development

Separate aqueous and ethanol extracts were prepared from the leaves and seed of 75 different Trigonella accessions and their ability to inhibit the growth of enteric bacteria and yeast was examined. No evidence of growth inhibition was observed, indicating that the Trigonella lines tested are suitable for forage development and animal consumption. Key words: Fenugreek, forage, antimicrobials, genetic diversity

AC longview alfalfa.

AC Longview alfalfa (Medicago sativa L.) was developed by the Agriculture and Agri-Food Canada Research Centre, Lethbridge, Alberta. This cultivar, tested as LRS 93-1 in Uniform Alfalfa Tests in western Canada, is highly resistant to verticillium wilt (VW) and bacterial wilt (BW) and out-yielded Beaver (check) by about 9 and 12% in dryland and irrigated locations, respectively. AC Longview is well suited for hay production, dehydration and silage in areas of western Canada, including British Columbia, where VW or BW reduces alfalfa yield and stand life. This cultivar produces good amount of seed both under dryland and irrigated conditions of western Canada. Key words: Cultivar description, alfalfa, Medicago sativa, disease resistance

Shearing force of alfalfa stems as affected by seeding rate

Physical properties of forages may provide a simple method of predicting animal voluntary feed intake. Physical measurements, such as shearing force, may indicate the resistance of the forage to particle breakdown during mastication. The objective of this study is to determine the effects of seeding rate on the physical characteristics and cell wall chemical constituents of alfalfa (Medicago sativa L.) stems, and to relate these characteristics to shearing strength. Stems of eight alfalfa cultivars (120, Legend, Multiking 1, OAC Minto, Saranac, Vernal, Vertus, WL320) seeded at 6, 12 and 24 kg ha−1 were harvested in the first and second production years and divided into three 16 cm segments: top, middle and bottom, and the force required to shear each segment was measured using a modified Ottawa Texture Measuring System. For both years, shearing force, segment weight and stem diameter measurements generally decreased as seeding rate increased when measured at the middle and bottom shearing segments on the ...

Effect of Verticillium wilt on forage yield of alfalfa in southern Alberta.

The incidence of Verticillim wilt and the forage yield of 12 cultivars of alfalfa (Medicago sativa) were compared in an irrigated field naturally infested with Verticillium albo-atrum near Lethbridge, Alberta. The alfalfa cultivars were seeded in 1986 and examined annually for Verticillium wilt and forage dry matter yield during 1987-1993. The incidence of wilt varied from year to year, and averaged over the years, the resistant cultivars Barrier, AC Blue J, Pioneer 5444, and Vertus had a significantly (P<0.01) lower incidence than the moderately resistant cultivar Maris Kabul, Admiral, and Trumpetor and the susceptible cultivars Excalibur, WL316, Apollo II, Beaver, and Pacer