Are two cultivars better than one? Performance of leafed and semi-leafless pea mixtures under weedy conditions

Non-Peer ReviewedThere is a need for improved tools to minimize yield losses due to weeds for organic field pea production. Cultivar mixtures may improve the ability of organic pulse crops to suppress weeds and maintain yields in the presence of weeds. While semi-leafless peas are known for their lodging resistance and high yield potential in the absence of weeds, leafed (wild-type) peas may provide better weed suppression and yield stability in the presence of weeds. A replicated field experiment was conducted on organic land over five site-years to test the hypothesis that mixtures of leafed and semi-leafless field pea cultivars would improve weed suppression and yields relative to monocultures of the same cultivars. The experiment tested factorial combinations of five ratios of semi-leafless (cv. CDC Patrick or CDC Dakota), and leafed pea (cv. CDC Sonata) (0:100, 25:75, 50:50, 75:25, and 100:0, respectively), and two target seeding rates (88 and 132 plants m-2). Plots were monitored for crop and weed emergence, biomass, and yields. Mixtures differed from their component monocultures in both weed control and yields. Levels of weed control in mixtures were intermediate to the component cultivars, and no weed control benefits were seen. While CDC Patrick mixtures did not out-yield CDC Patrick monocultures, mixtures of 75% CDC Dakota and 25% CDC Sonata out-yielded both respective monocultures by 12-196%. Results indicate that mixtures of leafed and semi-leafless cultivars may be used to improve organic pea yields in the presence of weeds. However, specific combinations of cultivars and mixing ratios should be evaluated on a case-by-case basis

Effect and underlying mechanisms of cultivar mixtures on weed and disease suppression in field pea (Pisum sativum)

Field pea is an important annual crop due to its contribution to soil fertility and other rotational benefits. However, weeds and ascochyta blight limit pea yield, particularly in organic systems. Leafed and semi-leafless pea types differ in lodging resistance, and may affect weeds and disease through differences in canopy light penetration and air flow. Mixtures of the two leaf types may improve weed and disease suppression and yield compared with monocultures of the same cultivars. To test this hypothesis, replicated field experiments were conducted under organic and conventional management in Saskatoon and Vonda, SK, in 2011 and 2012. Mixtures of a leafed and semi-leafless cultivar, CDC Sonata and CDC Dakota, were sown in ratios of 0:100, 25:75, 50:50, 75:25, and 100:0 leafed to semi-leafless pea, at target seeding rates of 88 and 132 plants m-2. Conventionally managed plots were inoculated with ascochyta blight-infested pea straw and received overhead irrigation to encourage disease. Mixtures of 50% or more semi-leafless pea adopted the greater lodging resistance and weed suppression of the semi-leafless cultivar. Mixtures comprised of 25% leafed and 75% semi-leafless pea increased both seed and biomass yield compared with either cultivar grown alone. Yield enhancement was attributed to the leafed cultivar, whose seed yield was 76% higher in mixture than expected based on monoculture yield. Ascochyta blight epidemics were of moderate severity, and leafed and semi-leafless monocultures reached 36 and 43% necrosis in 2011, and 33 and 38% necrosis in 2012, respectively. The disease reaction of mixtures fell between the two component cultivars. At disease onset in 2012, lower light interception and shorter moisture durations coincided with the lower ascochyta blight severity of leafed monocultures. In 2011 and the later phase of the 2012 epidemic, disease severity was negatively associated with vine length, and positively associated with number of nodes and tissue senescence. Despite the advantages of leafed and semi-leafless pea mixtures, the limited selection of leafed cultivars impedes adoption of this technique by growers. For pea breeders, developing mixtures of pea lines isogenic for leaf type may increase yield compared with single cultivars.

Increasing faba bean (Vicia faba) seeding rate under weedy and weed free conditions

Non-Peer Reviewe

Organic production tools for field peas: are cultivar mixtures more competitive with weeds?

Non-Peer ReviewedWithin Saskatchewan’s organic industry there is a need for improved tools to minimize yield losses due to weeds. Cultivar mixtures may improve the ability of organic pulse crops to suppress weeds and maintain yields in the presence of weeds. While semileafless peas are known for their lodging resistance and high yield potential in the absence of weeds, conventional peas may provide better weed suppression and yield stability in the presence of weeds. A replicated field experiment was conducted at two organic field sites to test the hypothesis that cultivar mixtures of conventional and semileafless field pea would differ in weed suppression and yields. The experiment tested factorial combinations of five ratios of semileafless pea cultivar CDC Dakota and conventional cultivar CDC Sonata (0:100, 25:75, 50:50, 75:25, and 100:0, respectively), and two seeding rates (conventional and organic recommended). Plots were monitored for crop and weed emergence, biomass, and yields. Significant differences were observed among the different ratios of semileafless and conventional field pea. Results indicate that the semileafless cultivar was more competitive with weeds than the conventional. As the canopy composition progressed from a pure conventional canopy towards increasing percentages of semileafless pea in the mixture, total weed biomass decreased, and total crop yields increased. It was concluded that while no additional weed suppression or yield benefits were seen compared with growing the more strongly competitive semileafless cultivar alone, cultivar mixtures reduced the risk associated with growing unfamiliar or less competitive cultivars by stabilizing weed suppression and crop yields at a level between the two components of the mixture

Application of Fluorescent Label in Polymer Nanofibers

The electrospinning of fluorescent probe polyamide 6 doped by 7H-benzimidazo[2,1-a]benzo[de]isoquinolin-7-on is presented as a model processing photoluminescent nanofibers. The presence of the fluorescent probe in the fiber layers was confirmed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR); the surface nanofiber structure was described by high-resolution fluorescence microscope and scanning electron microscope images. The prepared nanofibers with the fluorescent label were further characterized by fluorescence spectroscopy, both in the solid phase and in the solution

How can drones be used for crop diagnostics?

Non-Peer Reviewe

COMPARISON OF MODIFICATION SITES FORMED ON HUMAN SERUM ALBUMIN AT VARIOUS STAGES OF GLYCATION

Background—Many of the complications encountered during diabetes can be linked to the nonenzymatic glycation of proteins, including human serum albumin (HSA). However, there is little information regarding how the glycation pattern of HSA changes as the total extent of glycation is varied. The goal of this study was to identify and conduct a semi-quantitative comparison of the glycation products on HSA that are produced in the presence of various levels of glycation. Methods—Three glycated HSA samples were prepared in vitro by incubating physiological concentrations of HSA with 15 mmol/l glucose for 2 or 5 weeks, or with 30 mmol/l glucose for 4 weeks. These samples were then digested and examined by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify the glycation products that were formed. Results—It was found that the glycation pattern of HSA changed with its overall extent of total glycation. Many modifications including previously-reported primary glycation sites (e.g., K199, K281, and the N-terminus) were consistently found in the tested samples. Lysines 199 and 281, as well as arginine 428, contained the most consistently identified and abundant glycation products. Lysines 93, 276, 286, 414, 439, and 524/525, as well as the N-terminus and arginines 98, 197, and 521, were also found to be modified at various degrees of HSA glycation. Conclusions—The glycation pattern of HSA was found to vary with different levels of total glycation and included modifications at the 2 major drug binding sites on this protein. This result suggests that different modified forms of HSA, both in terms of the total extent of glycation and glycation pattern, may be found at various stages of diabetes. The clinical implication of these results is that the binding of HSA to some drug may be altered at various stages of diabetes as the extent of glycation and types of modifications in this protein are varied

Determination of Zinc, Cadmium, Lead, Copper and Silver Using a Carbon Paste Electrode and a Screen Printed Electrode Modified with Chromium(III) Oxide

In this study, the preparation and electrochemical application of a chromium(III) oxide modified carbon paste electrode (Cr-CPE) and a screen printed electrode (SPE), made from the same material and optimized for the simple, cheap and sensitive simultaneous determination of zinc, cadmium, lead, copper and the detection of silver ions, is described. The limits of detection and quantification were 25 and 80 mu g center dot L-1 for Zn(II), 3 and 10 mu g center dot L-1 for Cd(II), 3 and 10 mu g center dot L-1 for Pb(II), 3 and 10 mu g center dot L-1 for Cu(II), and 3 and 10 mu g center dot L-1 for Ag(I), respectively. Furthermore, this promising modification was transferred to the screen-printed electrode. The limits of detection for the simultaneous determination of zinc, cadmium, copper and lead on the screen printed electrodes were found to be 350 mu g center dot L-1 for Zn(II), 25 mu g center dot L-1 for Cd(II), 3 mu g center dot L-1 for Pb(II) and 3 mu g center dot L-1 for Cu(II). Practical usability for the simultaneous detection of these heavy metal ions by the Cr-CPE was also demonstrated in the analyses of wastewaters

Myosin light chain 1 isoform expression remains constant during ageing in Wistar F455 rats

In order to study muscle gene expression during ageing, we examined both protein and total cellular RNA from Wistar F455 rat soleus and extensor digitorum longus (EDL) muscles at a variety of chronological ages. We found no evidence of the reappearance of the fast protein isoform of myosin light chain 1 [MLC1] in the slow soleus muscle during ageing previously reported by Syrovy and Gutmann, Pflugers Arch., 369 (1977) 85-89. We used both SDS-PAGE analysis of MLC1 proteins and slot blot RNA analysis with a probe specific for rat fast MLC1 mRNA (pC91), and found no changes in fast MLC1 expression during ageing in soleus or EDL muscles from these rats. These results indicate that re-expression of the fast MLC1 isoform is not a universal property of ageing soleus muscle.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28987/1/0000014.pd