Stemphylium blight is a defoliating fungal disease caused by <i>Stemphylium botryosum</i>. It has become more prevalent in Saskatchewan. Although not much is known about the biology of the fungus, increasing lentil (Lens culinaris) yield losses of up 62% have been reported in Bangladesh and India. The infection of lentil by <i>S. botryosum</i> was investigated under a range of temperatures (5 to 30°C), wetness periods (0 to 48 h) and wetness periods interrupted by dry periods of 6 to 24 h. The experiments involved testing the impact of environmental conditions on germination of conidia on glass slides and stemphylium blight infection on lentil (cv. CDC Milestone). Generalised linear models and non-parametric tests were used to determine the effects of these factors on conidial germination and disease development. Infection levels increased with increasing temperature and wetness duration. A latent period of 48 h was observed at 25°C and 30°C under continuous wetness. The duration of the latent period increased with decreasing temperatures and decreasing wetness duration. <i>S. botryosum</i> required warm temperatures (above 25°C) and a minimum wetness period of 8 h for optimal disease development. Low levels of infection were observed within the first 2 h of incubation at 10°C and increased with longer wetting periods up to 48 h and temperatures up to 30°C. The pathogen could maintain infectivity during interrupted wetness periods despite its requirement for prolonged wetness periods. Infection levels were not significantly affected by interrupting dry periods of 6 to 24 h although long dry periods (24 h) combined with higher temperatures (30°C) resulted in a decrease in stemphylium blight severity. Germination studies on glass slides supported these findings. Response surface models were developed that provided a good fit for the response of conidial germination to temperature and wetness duration. The coefficients of determination for the regression of observed against predicted effects ranged from 0.88 to 0.97. The general additive model could also be used to predict stemphylium blight severity responses to temperature and wetness duration (scaled deviance = 1.04). However, that model tended to overestimate infection levels especially at lower temperatures. The coefficients of determination for the observed against predicted effects at 5 to 30ºC ranged from 0.77 to 0.92 for the general additive model.

Stemphylium blight of lentil caused by <i>Stemphylium botryosum</i> Wallr., is a serious problem in Bangladesh, northeast India and Nepal causing more than 60 % yield losses under epidemic conditions. The pathogen started to appear on lentil in Saskatchewan in recent years and is widely distributed throughout western Canada but it is not well understood. An investigation of inheritance of resistance to stemphylium blight was done in the lentil cross Barimasur-4 × CDC Milestone. In order to develop a reliable indoor screening technique for this inheritance study, a suitable isolate of <i>Stemphylium botryosum</i>, a suitable culture medium for inoculum production and an appropriate plant age for indoor inoculation were identified. The maximum differential of disease severity was observed when lentil genotypes were inoculated at 14 days after planting (DAP). At 14 DAP, lentil plants rapidly defoliated but were capable of regrowth which caused variability in scoring for disease reaction. Inoculation at 42 DAP, close to the flowering stage, was found to be better for consistently scoring disease reaction. V8P medium was most suitable for inducing conidia production. Based on ability to sporulate, the isolate SB-19 from Saskatchewan was identified as suitable for conducting genetic studies of resistance to stemphylium blight. It was compared to isolate SB-BAN from Bangladesh for aggressiveness on two lentil cultivars. The SB-BAN isolate was found to be more aggressive. A preliminary screening of local and exotic germplasm done with the two isolates revealed considerable variability for disease resistance. Resistance to <i>S. botryosum</i> appeared to be quantitatively inherited in the cross Barimasur-4 × CDC Milestone according to both field and indoor screenings. The results of this study also confirmed that Precoz, one of the parents of Barimasur-4, was resistant to <i>S. botryosum</i>.

Stemphylium blight is a defoliating fungal disease caused by <i>Stemphylium botryosum</i>. It has become more prevalent in Saskatchewan. Although not much is known about the biology of the fungus, increasing lentil (Lens culinaris) yield losses of up 62% have been reported in Bangladesh and India. The infection of lentil by <i>S. botryosum</i> was investigated under a range of temperatures (5 to 30°C), wetness periods (0 to 48 h) and wetness periods interrupted by dry periods of 6 to 24 h. The experiments involved testing the impact of environmental conditions on germination of conidia on glass slides and stemphylium blight infection on lentil (cv. CDC Milestone). Generalised linear models and non-parametric tests were used to determine the effects of these factors on conidial germination and disease development. Infection levels increased with increasing temperature and wetness duration. A latent period of 48 h was observed at 25°C and 30°C under continuous wetness. The duration of the latent period increased with decreasing temperatures and decreasing wetness duration. <i>S. botryosum</i> required warm temperatures (above 25°C) and a minimum wetness period of 8 h for optimal disease development. Low levels of infection were observed within the first 2 h of incubation at 10°C and increased with longer wetting periods up to 48 h and temperatures up to 30°C. The pathogen could maintain infectivity during interrupted wetness periods despite its requirement for prolonged wetness periods. Infection levels were not significantly affected by interrupting dry periods of 6 to 24 h although long dry periods (24 h) combined with higher temperatures (30°C) resulted in a decrease in stemphylium blight severity. Germination studies on glass slides supported these findings. Response surface models were developed that provided a good fit for the response of conidial germination to temperature and wetness duration. The coefficients of determination for the regression of observed against predicted effects ranged from 0.88 to 0.97. The general additive model could also be used to predict stemphylium blight severity responses to temperature and wetness duration (scaled deviance = 1.04). However, that model tended to overestimate infection levels especially at lower temperatures. The coefficients of determination for the observed against predicted effects at 5 to 30ºC ranged from 0.77 to 0.92 for the general additive model.

Stemphylium blight of lentil caused by <i>Stemphylium botryosum</i> Wallr., is a serious problem in Bangladesh, northeast India and Nepal causing more than 60 % yield losses under epidemic conditions. The pathogen started to appear on lentil in Saskatchewan in recent years and is widely distributed throughout western Canada but it is not well understood. An investigation of inheritance of resistance to stemphylium blight was done in the lentil cross Barimasur-4 × CDC Milestone. In order to develop a reliable indoor screening technique for this inheritance study, a suitable isolate of <i>Stemphylium botryosum</i>, a suitable culture medium for inoculum production and an appropriate plant age for indoor inoculation were identified. The maximum differential of disease severity was observed when lentil genotypes were inoculated at 14 days after planting (DAP). At 14 DAP, lentil plants rapidly defoliated but were capable of regrowth which caused variability in scoring for disease reaction. Inoculation at 42 DAP, close to the flowering stage, was found to be better for consistently scoring disease reaction. V8P medium was most suitable for inducing conidia production. Based on ability to sporulate, the isolate SB-19 from Saskatchewan was identified as suitable for conducting genetic studies of resistance to stemphylium blight. It was compared to isolate SB-BAN from Bangladesh for aggressiveness on two lentil cultivars. The SB-BAN isolate was found to be more aggressive. A preliminary screening of local and exotic germplasm done with the two isolates revealed considerable variability for disease resistance. Resistance to <i>S. botryosum</i> appeared to be quantitatively inherited in the cross Barimasur-4 × CDC Milestone according to both field and indoor screenings. The results of this study also confirmed that Precoz, one of the parents of Barimasur-4, was resistant to <i>S. botryosum</i>.

The Hurricane Lentil in the lower part of the Landrum Member of the Cook Mountain Formation can be recognized for 170 miles along strike. This lentil lies at the base of the Landrum Member and is directly above the Wheelock Member. Three key beds, two bentonites and a fossil bed containing Plicatula filamentosa Conrad , are present at most exposures of the Hurricane Lentil. Sedimentary rocks of the Cook Mountain Formation are classified using the four common constituents: quartz, iron oxide, glauconite pellets, and clay. The abundant fossils in the Hurricane Lentil indicate deposition took place on the continental shelf in a quiet, open marine sea with a level bottom. The lower Hurricane Lentil was deposited in a relatively stable sea whereas the upper Hurricane Lentil was deposited in a regressive sea. / text

No description available.

This study aimed to investigate the response of lentil genotypes to different water regimes, providing guide lines, through partitioning the variation, for a selection program for adaptation to irrigated conditions. The research was divided into two main areas; 1) The overall variation in the crop was partitioned into genotypic, environmental and genotype-environmental components in an analysis of adaptation over seasons, irrigation regimes and locations; 2) The genotypic variation was partitioned into its various genetic components in an inheritance study using the dial lei mating system. Pronounced progress should be expected from selection for number of pods/plant, 100 seed weight and straw yield/plant traits, which showed high estimates of h(^2)(_b.s), C.G.V. and G.S. The two former traits correlated strongly and positively with seed yield, which allowed their use in indirect selection for seed yield. The 35 genotypes used in this study showed wide genetic diversity, allowing selection of high yielding genotypes under irrigation. Environmental variation in water supply, temperature and soil type was found to exert a profound effect on variation in characters measured. This suggests the possibility of raising yield levels through improved management practices. In this study, irrigation repeated twice increased seed yield by 19% over no irrigation, at the same location, and increased the yield by 300% in comparison with a dry location. Seed protein quality was influenced by environments and genotypes. Electrophoretic studies showed that the number and position of the bands could be used to identify genotypes. Four genotypes showed response to irrigation and could be recommended as promising entries. An anatomical study showed that large air spaces formed in the roots of a responsive genotype:, which could be used as a selection criterion for positive response to irrigation. Seed yield/plant exhibited 31.8% heterosis and showed a predominant role of non-additive genetic variance. Due to the significance of the non-additive effect, the superior F(_1)'s may be expected to throw out desirable transgressive segregants, provided that the complementary genes and epistatic effects included in the non-additive component are coupled in the same direction to maximize seed yield. Five F(_2) crosses showed superiority in seed yield and SCA effects. These crosses should be carried forward in lentil breeding programs.

High levels of soil nitrogen (N) can interfere with N2 fixation of lentil (Lens culinaris) and have variable effects on growth, yield and maturity of this indeterminate crop in Saskatchewan. In a series of field and greenhouse experiments during 2006 to 2008, response of the above-ground biomass (DW), plant N, N2 fixation, yield and days to maturity (DTM) of lentil to different N sources, time of N availability, and also to two no tillage (NT) durations were studied. First, eight cultivars of lentil were grown under three fertility treatments of granular rhizobium inoculant, 50 kg N fertilizer ha-1 and a non-treated control in three environment-years at Saskatoon and Indian Head, SK. The fertility treatments, plant N status and N2 fixation did not alter lentil DTM, but weather did. On average, lentil matured 101 and 84 days after seeding with sufficient rain and with drought, respectively. Growth and yield of the lentil were identical in the inoculant and the N fertilizer treatments. The N fertilizer treatment occasionally restricted N2 fixation, but N shortage was compensated via more N uptake from soil. The greatest N accumulation of lentil occurred during podding to maturity and benefitted pod N content. By maturity, pod, stem and leaf had 60, 24 and 14% of total dry matter and 78, 9 and 13% of total plant N, respectively. Leaf N concentration, which closely resembled soil and plant N status, was reasonably predicted by SPAD chlorophyll meter observations after pod set. Yield of five lentil cultivars was tested for the effects of 25-years (LN) versus 5-years (SN) of no tillage in the Black Soil Zone at Indian Head, SK in 2006, 2007 and 2008. In the same location, CDC Sedley was grown with four N fertilizer rates at the both LN and SN. Under terminal drought in 2006, average DW, N content and yield of the lentil cultivars in SN were greater than in LN, likely because of inhibited N2 fixation by the amplified soil N in the LN. In this year, 60 kg N fertilizer ha-1 reduced the yield difference of CDC Sedley in SN and LN. Lentil yield was identical or tended to be greater in LN than in SN with more rain in 2007 and 2008 that prolonged N mineralization and N uptake. In the greenhouse study, applying N fertilizer from flowering until podding and until maturity increased DW, N content and yield, and delayed maturity of lentil compared to lentil relying on N2 fixation. Later flowering of one cultivar or greater N2 fixation in one soil medium diminished the variation of inoculated lentil with the post-flowering N treatments, suggesting N fixation could supply lentil N requirement. Large-seeded cultivars produced greater yield than the small-seeded cultivars across environments in the fertility treatment study. Cultivar CDC Milestone produced comparable yield to high-yielding cultivars CDC Plato and CDC Greenland, but matured earlier. This cultivar showed promising results under both cool-wet and drought conditions. In contrast, CDC Sedley had lower on N2 fixation and HI values across the experiments. In the Black Soil Zone, CDC Milestone and CDC Robin performance was improved by improved HI and N2 fixation. Overall, results of this thesis do not support the application of N fertilizer for inducing early maturity in lentil. Soil inoculation with commercial strains is suggested for Saskatchewan cropping systems. Applying N fertilizer is not required, unless soil test results suggest otherwise. In places like Indian Head, SK, cultivars with greater N2 fixation and higher HI can better fit the short growing season, cool temperature and high soil N content.

High levels of soil nitrogen (N) can interfere with N2 fixation of lentil (Lens culinaris) and have variable effects on growth, yield and maturity of this indeterminate crop in Saskatchewan. In a series of field and greenhouse experiments during 2006 to 2008, response of the above-ground biomass (DW), plant N, N2 fixation, yield and days to maturity (DTM) of lentil to different N sources, time of N availability, and also to two no tillage (NT) durations were studied. First, eight cultivars of lentil were grown under three fertility treatments of granular rhizobium inoculant, 50 kg N fertilizer ha-1 and a non-treated control in three environment-years at Saskatoon and Indian Head, SK. The fertility treatments, plant N status and N2 fixation did not alter lentil DTM, but weather did. On average, lentil matured 101 and 84 days after seeding with sufficient rain and with drought, respectively. Growth and yield of the lentil were identical in the inoculant and the N fertilizer treatments. The N fertilizer treatment occasionally restricted N2 fixation, but N shortage was compensated via more N uptake from soil. The greatest N accumulation of lentil occurred during podding to maturity and benefitted pod N content. By maturity, pod, stem and leaf had 60, 24 and 14% of total dry matter and 78, 9 and 13% of total plant N, respectively. Leaf N concentration, which closely resembled soil and plant N status, was reasonably predicted by SPAD chlorophyll meter observations after pod set. Yield of five lentil cultivars was tested for the effects of 25-years (LN) versus 5-years (SN) of no tillage in the Black Soil Zone at Indian Head, SK in 2006, 2007 and 2008. In the same location, CDC Sedley was grown with four N fertilizer rates at the both LN and SN. Under terminal drought in 2006, average DW, N content and yield of the lentil cultivars in SN were greater than in LN, likely because of inhibited N2 fixation by the amplified soil N in the LN. In this year, 60 kg N fertilizer ha-1 reduced the yield difference of CDC Sedley in SN and LN. Lentil yield was identical or tended to be greater in LN than in SN with more rain in 2007 and 2008 that prolonged N mineralization and N uptake. In the greenhouse study, applying N fertilizer from flowering until podding and until maturity increased DW, N content and yield, and delayed maturity of lentil compared to lentil relying on N2 fixation. Later flowering of one cultivar or greater N2 fixation in one soil medium diminished the variation of inoculated lentil with the post-flowering N treatments, suggesting N fixation could supply lentil N requirement. Large-seeded cultivars produced greater yield than the small-seeded cultivars across environments in the fertility treatment study. Cultivar CDC Milestone produced comparable yield to high-yielding cultivars CDC Plato and CDC Greenland, but matured earlier. This cultivar showed promising results under both cool-wet and drought conditions. In contrast, CDC Sedley had lower on N2 fixation and HI values across the experiments. In the Black Soil Zone, CDC Milestone and CDC Robin performance was improved by improved HI and N2 fixation. Overall, results of this thesis do not support the application of N fertilizer for inducing early maturity in lentil. Soil inoculation with commercial strains is suggested for Saskatchewan cropping systems. Applying N fertilizer is not required, unless soil test results suggest otherwise. In places like Indian Head, SK, cultivars with greater N2 fixation and higher HI can better fit the short growing season, cool temperature and high soil N content.

In recent years global concern over the development of herbicide resistant (HR) weeds has lead to interest in integrated weed management (IWM) strategies. IWM seeks to relieve selection pressure for herbicide resistance by utilizing mechanical and cultural controls in addition to herbicides. The situation experienced by Saskatchewan lentil growers with large populations of group 2 herbicide resistant wild mustard provides an ideal model system to test our hypothesis that IWM strategies can provide robust weed management and maintain crop yields. The first study evaluated an IWM method targeting HR wild mustard in lentil. This study was conducted for 3 years between 2011 and 2013 at 2 locations at Saskatoon and Scott, Saskatchewan. It was a randomized two way factorial with weed control method and seeding rate as the main effects. Weed control treatments tested consisted of a control treated with a glyphosate burnoff, saflufenacil (Heat ™) herbicide, rotary hoeing, half rate metribuzin (Sencor ™) herbicide, a fully integrated treatment, and a full herbicide treatment. Three seeding rates representing 1, 2, and 4 times the recommended seeding rate were tested. The integrated treatment relied on increased seeding rate to reduce mustard biomass and produce yield, and at the highest seeding rate it was able to provide equivalent yield to the full herbicide system. The results of this study show that an integrated system utilizing an increased seeding rate can control resistant weeds and maintain yields to a similar level as a strategy that relies only on herbicides for weed control. The cultural practice of increasing crop seeding rate has been identified as having potential to provide non-chemical weed control and enhance the effects of herbicide application. The objective of the second study was to examine the interaction between increasing seeding rate and the dose response relationship of weeds to herbicide application. The experiment was a factorial design with four levels of lentil seeding rate and seven levels of fluthiacet-methyl herbicide application rate. The study was conducted at two locations near Saskatoon, Sk. in 2012 and 2013. Results of the experiment show that increasing lentil seeding rate decreased the total mustard biomass when herbicides were not applied or were applied at low rates. In addition increasing lentil seeding rate lowered the herbicide dose required to result in a 50% reduction in mustard biomass in 2012, though it had little effect in 2013. These results suggest that the practice of increasing seeding rate can work with herbicide application to reliably and effectively control weeds, even in situations where herbicides alone may not achieve good control.