Five registered Canadian six-row barley (Hordeum vulgare L.) cultivars, including two recently registered semidwarfs ('Duke' and 'Samson'), that differ in lodging resistance and height were studied over 2 years for differences in morphological and anatomical characteristics of culms that could be related to lodging resistance. Plants were grown in nonirrigated field plots at a population density of 220 plants/m2 under conditions of high soil fertility. Significant cultivar differences were observed for culm length, number of internodes, length of four basal internodes, culm diameter, culm wall thickness, number of vascular bundles, and thickness of the sclerenchyma ring. No cultivar differences were found for thickness of the sclerenchyma cell walls. Of the characters studied, culm length, basal internode length, culm wall thickness, and sclerenchyma ring thickness were most closely associated with differences in lodging resistance among the cultivars. The results of this study indicate that it may be possible to select lodging resistant genotypes from early generations in breeding programs on the basis of these traits.

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. 2000. Variation amongst Canadian six-row spring barley cultivars for germination and emergence characteristics in controlled environments and in the field. Can. J. Plant Sci. 80: 247-253. Information is lacking concerning the extent of variability in Canadian six-row barley cultivars for differences in potential field germination vigour and other germination characteristics, and the extent to which these traits can be predicted from laboratory tests. This study was conducted to evaluate the extent to which a genetically diverse range of Western Canadian six-row barley cultivars differ in germination resistance and early seedling vigour or emergence rate under controlled environments and in the field, over a range of temperature stress conditions. Vigour was assessed by measuring germination rate, emergence rate, and dry weight accumulation in young seedlings, in the growth cabinet and in the field. Cultivars studied were selected to represent a wide range of genetic diversity typical of Canadian breeding programs of the early 1980s. Growth cabinet assays were conducted at six temperatures from 2.5 to 20°C. Field trials were conducted using the same cultivars seeded at three dates per site in 2 yr, to assess cultivar emergence rates and seedling dry weight accumulation over a range of seedbed temperatures, using two seed sources from cultivar increases each grown in different years.Cultivars differed significantly for germination resistance in the growth cabinet, and the performance of cultivars was relatively consistent across assay temperatures and for the two different seed sources. Differences among cultivars in growth for seedling dry weight were also consistent across temperatures, but cultivar performance for seedling dry weight accumulation was not significantly correlated with germination resistance in the cabinet test. In field trials, days to emergence were highly and significantly correlated with germination resistance determined in the growth cabinet. Germination resistance was less strongly correlated with dry weight accumulation in the field at 5 wk. Across cultivars, seedling dry weight estimates in the field were significantly correlated with seedling dry weights assayed in the growth cabinet. Results from this study confirm that genetic variation in potential germination rate and seedling vigour in the field can be identified in six-row barley using the germination resistance assay in the growth cabinet. Germination resistance identified more cultivar differences than were found for the seedling dry weight accumulation tests, which were characterized by high coefficients of variation and low correlation between growth cabinet and field. Les cultivars choisis étaient représentatifs de la large diversité génétique utilisée dans les programmes de sélection appliqués au Canada dans le début des années 1980. Les essais en enceinte climatisée étaient réalisés à six températures ambiantes, allant de 2,5 à 20°C. Dans les essais au champ, les mêmes cultivars étaient semés à trois dates de semis par emp...

. 1999. Predicting potential field seedling vigour of Canadian six-row barley cultivars. Can. J. Plant Sci. 79: 329-334. Rapid techniques for predicting the field vigour potential of barley seed samples would be very useful for seed-testing laboratories and barley breeders. The objective of this study was to compare two faster laboratory seed-testing methods, tetrazolium chloride reduction (TZ) and carbon dioxide evolution rate (CDE), with the standard, but slow and costly germination resistance (GR) test, for ability to identify cultivar differences in vigour and their relationship to vigour potential in the field. Fifteen six-row barley (Hordeum vulgare L.) cultivars were used in the study, from two seed sources grown in different years, and four replicate assays of all three tests were conducted in controlled conditions at 5, 10, 15 and 20°C. Field emergence rate (FDE = days to 75% seedling emergence) was also assessed in replicated plot trials grown at Edmonton and Ellerslie, Alberta in 1997, using the same seed sources. Three seeding dates were used at each site to obtain a range of soil temperatures at planting depth from 4 to 18°C. Significant differences between cultivars were found for TZ, CDE and GR, but not between seed sources, and little or no interaction of cultivar with assay temperature was found. Cultivar performance was relatively similar when assessed by TZ or CDE, at all temperatures. CDE, TZ and GR results from all temperatures and both seed sources were compared by correlation to FDE results for all six planting events (two field sites × three planting dates). High and significant correlations (r > 0.51; sig., P < 0.05) were found for nearly all comparisons of each of CDE, TZ and GR with FDE. For all comparisons with FDE the average correlation for TZ was 0.68, 0.66 for CDE, and 0.69 for GR, with 10% of all possible correlations exceeding 0.80 (all sig., P < 0.05). These results indicate that all three laboratory tests at any temperature were generally effective predictors of the potential field seedling vigour of different barley cultivars. TZ and CDE appear to be useful alternatives to GR for assessing potential field seedling vigour of barley cultivars, and lend themselves to development of automated laboratory assay procedures, not possible for GR. Nous avons comparé deux méthodes rapides d'essai en laboratoire, la méthode de réduction du chlorure de tétrazolium (TZ) et la mesure du taux de dégagement du dioxyde de carbone (DBC) à la méthode standard, mais lente et onéreuse, de la résis-tance à la germination (RG) quant à leur capacité d'identifier les différences intervariétales de vigueur ainsi que leur vigueur potentielle au champ. Les 15 cultivars d'orge à six rangs (Hordeum vulgare L.) utilisés venaient de deux provenances de semence récoltées dans des années différentes. Des tests biologiques en 4 répétitions des trois méthodes étaient réalisés en conditions contrôlées à 5, 10, 15 et 20°C. En outre, à Edmonton et à Ellerslie (Alberta), le taux de levée au champ (TLC), soit le nomb...

In a field experiment conducted near Fort Collins, Colorado, we monitored seasonal trends in soluble carbohydrate (SC) concentrations in sugarbeet (Beta vulgaris). Three N fertility levels (0, 100, and 300 lb NIA) and two planting dates (April 22 and May 27) were imposed to study the SC concentration in four plant p arts (leaf blade, petiole, crown, and taproot) at biweekly intervals from June 27 to September 5, then a final sampling on October 18, 1977. We found that: 1) increasing N-fertilization decreased SC con centration (% of dry weight) when averaged for all plant parts; 2) roots were highest in SC concentration followed in decreasing order by crowns, petioles, and blades; 3) when averaged for all plant parts, the maximum rate of increase in SC concentration oc curred between June 27 and August 22; 4) early plant ing increased SC concentration in crowns and roots, but had little effect on SC concentration in blades or petioles; 5) SC concentrations were higher in early planted than later-planted sugarbeets until August 22, but thereafter there was no difference; 6) SC con centrations in blades and crowns increased linearly as the season advanced, but root SC was a maximum by August 22; 7) early planting increased the SC con centration in roots until August 10; thereafter, there was no difference between planting dates; and 8) plan ting date had variable effects on SC in the petioles, b ut SC in blades was unaffected by planting date.