Does Wheat Cultivar Choice Affect Crop Quality and Soil Microbial Communities in Cropping Systems?

Wheat (Triticum aestivum L.) cultivars may have differential effects on soil microbial communities and the breadmaking quality of harvested grain. We compared six Canadian spring wheat cultivars under organic and conventional management systems for yield, breadmaking quality and soil phospholipid fatty acid analysis (PLFA) profile. Yields were lower, but protein levels were higher in the organic system. Cultivars differed for quality traits, but all cultivars had acceptable levels for processing. There were small differences in PLFA profiles for cultivars in the conventional system, but none in the organic system. More significant correlations between grain quality and PLFA measures were present in the organic system. Protein levels and breadmaking quality at least equal to conventional systems can be achieved in organic systems. Wheat cultivars differed for grain quality in both organic and conventional systems, and culivars altered the soil microbial profile in conventional systems. Microbes may play a greater role in determining crop quality in organic systems than in conventional systems

Farmer-Directed On-Farm Experimentation Examining the Impact of Companion Planting Barley and Oats on Timothy-Lucerne Forage Establishment in Central Newfoundland

Growing barley or oats in the year of forage establishment is a common agronomic practice in marginal growing regions, but is often not recommended to growers in Newfoundland. Spaner & Todd (2003) reported that barley seeded at rates of 100-150 kg seed/ha and undersown with a timothy-clover mixture (harvested at mid-milk) resulted in the planting year in greater forage yield of poorer quality than pure-stand timothy-clover. A barley seeding rate of 100 kg seed/ha did not impede forage production in the subsequent year

The Sustainability of Organic Grain Production on the Canadian Prairies—A Review

Demand for organically produced food products is increasing rapidly in North America, driven by a perception that organic agriculture results in fewer negative environmental impacts and yields greater benefits for human health than conventional systems. Despite the increasing interest in organic grain production on the Canadian Prairies, a number of challenges remain to be addressed to ensure its long-term sustainability. In this review, we summarize Western Canadian research into organic crop production and evaluate its agronomic, environmental, and economic sustainability

Chapter 2 B Lymphocytes in Cancer Immunology

Abstract The role of B lymphocytes in the pathogenesis and treatment of cancer has not received as much attention as the role of T cells. However, most patients with solid tumors harbor circulating antitumor antibodies and most tumors contain a population of infiltrating B cells implying an association between oncogenic events and B-cell activation. B-cell immunity can be beneficial by providing antibody-mediated protection from oncogenic viruses or a source of recombinant tumor-specific antibodies that can be used in combination with chemotherapeutic regimens. However, activation of B cells may also be detrimental to an effective antitumor response. Tumor-reactive antibodies and B cells often recognize antigens that are generated during the unscheduled apoptotic and necrotic death processes, which accompany tumor progression and may be involved in wound-healing processes that promote tumor growth and impair protective T-cell responses. Therefore, methods to eliminate autoreactive B cells, or switch them to a B effector-1 (Be-1) phenotype that amplifies Th1/Tc1-type T-cell responses, which are typically associated with effective antitumor responses, may improve the clinical outcomes of T-cell-mediated immunotherapies. Possible strategies include the administration of B-celldepleting monoclonal antibodies, use of targeted B-cell stimulatory agents such as Toll-like Receptor agonists, and adoptive transfer of large numbers of ex vivo generated tumor-reactive Be-1 cells

WEEDS PROMOTE THE DEVELOPMENT OF ARBUSCULAR MYCORRHIZAL FUNGI IN ORGANIC WHEAT FIELDS

Understanding the interaction between aboveground vegetation and arbuscular mycorrhizal fungi (AMF) in organic agriculture is of great importance to develop more efficient and sustainable agricultural production systems. This study was conducted to evaluate the effect of weeds on AMF and the effect of AMF on wheat (Triticum aestivum L.) grain quality in an organic field in the weed-free and weedy conditions. The soil microbial profile was characterized using phospholipid fatty acids (PLFA) analysis. We found that the presence of weeds increased the proportion of AMF. The enhanced activity of AMF did not affect the quality of wheat grain grown with sufficient soil phosphorus (P)

Improvement of the agricultural sustainability and livelihoods of poor farmers through biotechnology : reality or speculation?

Poverty reduction, food security, and agricultural sustainability require that the livelihoods of poor farmers be improved. The potential of biotechnology to improve the livelihoods and agricultural sustainability of farmers has been hotly debated and primarily focused on “modern” agricultural biotechnology. Biotechnology is much broader than this narrow focus and includes “traditional” biotechnologies, as well as, industrial and medical sectors. Different biotechnology types have different effects and these impacts are molded by the macro-economic policies of the countries where they are implemented. Generally, the problems of poor farmers are not technological and the benefits of biotechnology are unlikely to reach poor farmers unless these ‘non-technical’ problems are addressed first

Maize and upland rice traits of importance for farmers practicing manual rainfed agriculture in the humid tropics : a Panamanian case-study

The agronomic practices and concerns of poor farmers in comparable ecozones are often similar across countries and regions. Crop ideotypes have helped guide selection for yield under high fertility monoculture conditions in formal breeding programs and could be used to direct breeding for the agricultural conditions of poor farmers. However, the objectives and selection criteria of poor farmers may differ from those of formal breeding programs. This study illustrates a simple survey method for detecting crop traits that are important to poor farmers, and describes results for upland rice and maize ideotypes cropped by swidden agriculturalists in Panama. Our results suggest that formal breeding programs are working on individual crop traits that are important to poor farmers, but they may not be developing varieties that incorporate multiple individual traits (ideotypes), which farmers desire. National breeding programs should play crucial roles in identifying and breeding for regional ideotypes that vary with farming practices and cultural preferences. The field survey techniques reported herein are reproducible, quickly orient breeders towards crop traits that are potentially important to farmers, provide information on the processes underpinning trait importance, and capitalize on decades of farmer experience

The expression of caffeic acid 3-O-methyltransferase in two wheat genotypes differing in lodging resistance

Stem lodging-resistance is an important phenotype in crop production. In the present study, the expression of the wheat COMT gene (TaCM) was determined in basal second internodes of lodging-resistant (H4564) and lodging-susceptible (C6001) cultivars at stem elongation, heading, and milky endosperm corresponding to Zadoks stages Z37, Z60, and Z75, respectively. The TaCM protein levels were analysed by protein gel blot and COMT enzyme activity was determined during the same stem developmental stages. TaCM mRNA levels were higher in H4546 from elongation to the milky stages and in C6001 the TaCM mRNA levels decreased markedly at the heading and milky stages. The TaCM protein levels and COMT activity were also higher in H4564 than that in C6001 at the heading and milky stages. These results corresponded to a higher lignin content measured by the Klason method and stem strength and a lower lodging index in H4564 than in C6001 at the heading and milky stages. Therefore, the TaCM mRNA levels, protein levels, and enzyme activity in developing wheat stems were associated with stem strength and lodging index in these two wheat cultivars. Southern analysis in a different population suggested that a TaCM locus was located in the distal region of chromosome 3BL, which has less investigated by QTL for lodging-resistant phenotype

Genomic Prediction Accuracy of Stripe Rust in Six Spring Wheat Populations by Modeling Genotype by Environment Interaction

Some previous studies have assessed the predictive ability of genome-wide selection on stripe (yellow) rust resistance in wheat, but the effect of genotype by environment interaction (GEI) in prediction accuracies has not been well studied in diverse genetic backgrounds. Here, we compared the predictive ability of a model based on phenotypic data only (M1), the main effect of phenotype and molecular markers (M2), and a model that incorporated GEI (M3) using three cross-validations (CV1, CV2, and CV0) scenarios of interest to breeders in six spring wheat populations. Each population was evaluated at three to eight field nurseries and genotyped with either the DArTseq technology or the wheat 90K single nucleotide polymorphism arrays, of which a subset of 1,058- 23,795 polymorphic markers were used for the analyses. In the CV1 scenario, the mean prediction accuracies of the M1, M2, and M3 models across the six populations varied from 0.11 to 0.07, from 0.22 to 0.49, and from 0.19 to 0.48, respectively. Mean accuracies obtained using the M3 model in the CV1 scenario were significantly greater than the M2 model in two populations, the same in three populations, and smaller in one population. In both the CV2 and CV0 scenarios, the mean prediction accuracies of the three models varied from 0.53 to 0.84 and were not significantly different in all populations, except the Attila/CDC Go in the CV2, where the M3 model gave greater accuracy than both the M1 and M2 models. Overall, the M3 model increased prediction accuracies in some populations by up to 12.4% and decreased accuracy in others by up to 17.4%, demonstrating inconsistent results among genetic backgrounds that require considering each population separately. This is the first comprehensive genome-wide prediction study that investigated details of the effect of GEI on stripe rust resistance across diverse spring wheat populations