Development of a rating scheme to evaluate root nodulation in chickpea (Cicer arietinum)

Non-Peer ReviewedChickpea (Cicer arietinum) has become an important pulse crop in the Brown Soil Zone of the Canadian prairies with about one million acres (over 400 000 ha) seeded in Saskatchewan alone in 2001. As with most legumes, chickpea can fix nitrogen from the atmosphere when the plant forms active root nodules. Active root nodules are formed when the proper strain of Rhizobium bacterial inoculant is provided for the crop and together the plant and bacteria make a nitrogen fertilizer “factory”. Not enough active nitrogen-fixing root nodules can result in substantially decreased plant production and grain yield potential (Green and Biederbeck 1995). Root nodulation rating schemes have been developed for other legume crops and these have been useful for researchers and producers to evaluate production potential (Rice et al. 1977, Rice and Clayton 1996). The presently available schemes emphasize nodule number, size, colour and in some cases distribution of nodules throughout the root system as important factors for assessment. Preliminary field investigations have shown that existing root nodulation rating schemes are inadequate for use as tools to predict chickpea grain yield potential. The objective of this study was to develop a root nodulation rating scheme to assess the effective root nodulation of chickpea that may determine if maximum yield potential will be realized

Fungicide application effects on diversity components of chickpea rhizospheric bacterial community

Non-Peer ReviewedMolecular (polymerase chain reaction – denaturing gradient gel electrophoresis) methods and correspondent analysis have been used in order to test changes of the diversity of bacterial communities in chickpea rhizospheric soil under different cultivars and fungicide treatments. Results showed that chickpea genotypes influence their microbial environment differently. Besides, fungicide applications could negatively affect the diversity of dominant bacterial DNA sequences, and this effect increased with the number of fungicide application on chickpea aerial parts

Physiological characteristics of recent Canada western red spring wheat cultivars: nitrogen uptake and remobilization

Non-Peer ReviewedGenetic yield gains have been difficult to achieve within the CWRS wheat class because of stringent quality requirements, and a growing-season environment of low precipitation and high temperatures. Understanding the physiological basis of yield gains may provide breeders with better insight as to the selection of parents, or provide screening tools to identify desirable genotypes. The objective of the present study was to compare four new CWRS wheat cultivars, which averaged higher yields than Neepawa in three years of multi-location testing within registration trials, both as a group and individually while maintaining or even increasing protein content, with two older cultivars, Neepawa and Marquis, in terms of N uptake and N remobilization. Results indicated that new cultivars had higher N uptake and/or higher N remobilization than old cultivars. Low tissue N concentration at maturity could be a criterion for selecting high-yielding and high-protein cultivars.Grain protein concentration (GPC) is an important trait of major interest in breeding of bread wheat (T. aestivum L.), because it determines both baking and nutritional properties. Breeding for both high yield and high GPC is very difficult as a negative relationship between yield and GPC was found by many studies (Simmonds 1995; McNeal, et al., 1972; Whitehouse, 1973; Bhatia, 1975; Costa and Kronstad, 1994). Simmonds (1996), therefore, concluded that high yield and high GPC were unattainable simultaneously. However, Kibite and Evans (1984) indicated that the negative relationship between yield and GPC was not primarily driven by genetic factors, but mainly by environmental factors. Cox et al. (1985) found that negative correlations between yield and GPC for some wheat lines were low, although significant, which indicated that simultaneous increase in yield and GPC could be achieved by selection. This is supported by some studies (Davis et al., 1961; Terman et al. 1969; Johnson, 1978; McKendry et al. 1995). Jenner et al. (1991) indicated there is no fundamental conflict on physiological grounds in selecting cultivars for high carbohydrate yield at acceptable, even high, levels of GPC. GPC is determined by plant total nitrogen (N) uptake and N remobilization to the grain. Many studies found genetic differences in N uptake (Löffler, et al. 1985; Van Sanford and MacKown, 1986; Le et al. 2000; Desai and Bhatia, 1978; McKendry, et al. 1995), while Oscarson et al. (1995) did not find any major differences in NO3 uptake capacity among wheat grown hydroponically. A positive correlation between N uptake and GPC was found by Beninati and Busch (1992) and McKendry et al. (1995), but not by others (McNeal et al. 1966; Johnson et al. 1967; Desai and Bhatia 1978). Cultivar difference in N remobilization was also found by some authors (Seth et al. 1960; Johnson et al. 1968; Van Sanford and MacKown, 1987). However, the relationship between plant N metabolism and GPC was not clear. Some reported that N partitioning was associated with GPC (Johnson et al. 1968; Cox et al. 1986; McKendry et al. 1995), but others (McNeal et al. 1972; Woodruff 1972; Van Sanford and MacKown 1987; May et al. 1991) did not support this. Nitrogen harvest index was (grain N at maturity/maximum N uptake, %) used as a selection criterion by some authors (Desai and Bhatia 1978; Cregan and Berkum 1984; Löffler et al. 1985; Jenner et al. 1991; McKendry et al. 1995). Borghi et al. (1987) suggested that both higher biomass yield and efficiency of N remobilization are important traits to overcome the negative relationship between grain yield and GPC. Some studies suggested to use tissue N (Rostami and Giriaei 1998; Rostami and O'Brien 1996; Sylvester-Bradley 1990) or tissue protein concentrations (Noaman and Taylor 1990; Noaman et al. 1990) as selection criteria for increasing GPC because they were positively correlated with GPC. However, Jenner et al. (1991) indicated that from a physiological point of view, there is little logic in using grain protein percentage as a selection criterion. Delzer et al. (1995) also pointed that selection for grain protein only is questionable because the higher GPC is often associated with lower grain yield. Although there are not short of studies on N mechanisms, there are lack of consistencies in the results. Clarke et al. (1990) indicated that unless greater variation in N utilization parameters among cultivars can be demonstrated, there seems to be little justification for selection for parameters other than grain yield and protein concentration. Some recently developed bread wheat cultivars in western Canada have significantly increased yields, while maintaining or increasing percent protein content, relative to earlier cultivars (Wang et al. 2002). These cultivars can be used to study the physiological basis for these genetic improvements in N utilization. A better understanding of these improvements may allow breeders to design more efficient screening methods to develop future high yield and high GPC cultivars. This information may also assist agronomists and producers design soil and crop management practices that will permit full expression of these improved traits. The objective of this study was to estimate the characteristics of these new cultivars in N utilization in comparison with older cultivars and to identify potential criteria for selection of high yield and high GPC cultivars in the western Canadian semiarid prairie

Genotype difference in kernel discolorations in CWRS and CWAD wheats

Non-Peer ReviewedKernel discolorations of wheat, such as black point (including smudge and penetrated smudge), red smudge and Fusarium-damaged kernel (FDK), are important downgrading factors in western Canada. This study was undertaken to determine cultivar differences in incidences of these kernel discolorations and their downgrading effects in CWRS and CWAD wheats. Grain samples were taken at maturity from six CWRS and four CWAD cultivars in a four-year (1997-2000) field study at six sites: one in the Grey soil zone, two in the Brown soil zone and three in the Black soil zone in western Canada. For CWRS cultivars, Garnet tended to have lower incidences in black point, smudge and FDK and resulted in the least downgrading compared with other CWRS cultivars. For CWAD cultivars, Kyle tended to have lower incidence of black point, Plenty had less smudge caused downgrading effects, DT 369 had lower penetrated smudge incidence, but higher red smudge incidence, and Plenty tended to have severer FDK-caused downgrading effects compared with other CWAD cultivars. CWAD class had higher frequency of downgrading than CWRS class and it usually had higher incidences of all kernel discolorations (black point, smudge, penetrated smudge, red smudge and FDK) and greater downgrading effects than CWRS class

Water use efficiency and precipitation use efficiency of crops in the semiarid prairie

Non-Peer ReviewedThe importance of water use efficiency (WUE) in crop production, in the semiarid prairie, is based on the fact that the available water is the most limiting factor influencing crop production. This poster compares water use efficiency of four crop rotations from the Swift Current, SK, long-term rotation experiment: fallow-wheat-wheat (F-W-W), F-flax-W (F-Flx-W), continuous wheat (Cont W) and wheat-lentil (W-Lent). We found that, the WUE of flax and lentil averaged 50% and 64%, respectively, of wheat following wheat. The precipitation required per unit of produce from the complete cropping system (PUE) increased with cropping intensity on a yield basis (kg ha-1 mm-1): Cont W (4.8) > W-Lent (4.2) > F-W-W (4.1) > F-Flx-W (2.9) (opposite response to WUE) and when PUE was calculated on a dollars produced per rotation basis ($ ha-1 mm-1): W-Lent (1.0) was higher than the other two rotations (0.6 to 0.7)

Productivity and economic performance of spring wheat production using conventional tillage practices in southwestern Saskatchewan – revisited

Non-Peer Reviewe

Observation of rotational bands in the neutron-rich 107Ru nucleus

Levels in the neutron-rich, odd-mass 107Ru nucleus have been reinvestigated with Gammasphere by measuring high-fold, prompt coincidence events following spontaneous fission of 252Cf. The ground state band has been extended up to 27/2ℏ. The structure associated with the h11/2 excitation has been confirmed and extended to higher spin. The h11/2 band head has been established to lie at 301.8 keV. These results clear up differences between our earlier work and results from another experiment published recently. A new collective band based on a 9/2- level has been identified for the first time. Some distinct features of the level scheme are discussed

Search for the Zγ decay mode of new high-mass resonances in pp collisions at √s = 13 TeV with the ATLAS detector

This letter presents a search for narrow, high-mass resonances in the Zγ final state with the Z boson decaying into a pair of electrons or muons. The √s = 13 TeV pp collision data were recorded by the ATLAS detector at the CERN Large Hadron Collider and have an integrated luminosity of 140 fb−1. The data are found to be in agreement with the Standard Model background expectation. Upper limits are set on the resonance production cross section times the decay branching ratio into Zγ. For spin-0 resonances produced via gluon–gluon fusion, the observed limits at 95% confidence level vary between 65.5 fb and 0.6 fb, while for spin-2 resonances produced via gluon–gluon fusion (or quark–antiquark initial states) limits vary between 77.4 (76.1) fb and 0.6 (0.5) fb, for the mass range from 220 GeV to 3400 GeV

Search for boosted diphoton resonances in the 10 to 70 GeV mass range using 138 fb−1 of 13 TeV pp collisions with the ATLAS detector

A search for diphoton resonances in the mass range between 10 and 70 GeV with the ATLAS experiment at the Large Hadron Collider (LHC) is presented. The analysis is based on pp collision data corresponding to an integrated luminosity of 138 fb−1 at a centre-of-mass energy of 13 TeV recorded from 2015 to 2018. Previous searches for diphoton resonances at the LHC have explored masses down to 65 GeV, finding no evidence of new particles. This search exploits the particular kinematics of events with pairs of closely spaced photons reconstructed in the detector, allowing examination of invariant masses down to 10 GeV. The presented strategy covers a region previously unexplored at hadron colliders because of the experimental challenges of recording low-energy photons and estimating the backgrounds. No significant excess is observed and the reported limits provide the strongest bound on promptly decaying axion-like particles coupling to gluons and photons for masses between 10 and 70 GeV