Hoersrna, G. J., Ker.rNsNBERG

. Relationships between planting date, winter survival and stress tolerances of soft white winter wheat in eastern Ontario. Can. J. Plant Sci. 77: 507-513. Reduction of populations of fall planted crops in the course of winter can result in substantial losses in economic yield. Variations in planting date of soft white winter wheat (Triticum aestivum L.) in eastern Ontario are known to influence both survival and grain yield. This study was conducted to determine relationships between fall-accumulated growing degree days (GDD), cold hardiness, ice tolerance and a number of plant characteristics with survival recorded the next spring. Locations were at Ottawa (45°23′N) and Douglas (45°33′N) with four planting dates, 27 August, 10 September, 24 September and 8 October in 4 yr, 1983-1986. Delayed planting was associated with reduced survival at Ottawa in 1987 and in all years at Douglas. Consequently, survival at Ottawa showed little association with cold hardiness and ice tolerance, but there were significant correlations at Douglas. Measurements in 3 yr showed that late planted wheats were single tillered, up to 10 times lower fresh weight than the 3-5 tillered August-planted wheat, and their cold hardiness and ice tolerance were decreased. Moisture content of the crown tissue (CrW) increased with delayed planting despite the growth of the plants in acclimating conditions. Highest CrW developed in late-planted wheat at Douglas and showed a high negative correlation with survival. Cold hardiness and ice tolerance correlated with survival at Douglas and there were significant relationships between the stress tolerances. However, no consistent associations across location-years could be defined to explain winter survival in terms of fall-measured stress tolerances and plant parameters. Key words:Cold acclimation, cold hardiness, crown moisture, winter injury, ice encasement, delayed planting Andrews, C. J., Pomeroy, M. K., Seaman, W. L., Butler, G., Bonn, P. C. et Hoekstra, G. 1997. Liens existants entre la date de semis, le taux de survie à l'hiver et la tolérance aux stress chez le blé d'automne blanc tendre dans l'est de l'Ontario. Can. J. Plant Sci. 77: 507-513. La baisse de densité de peuplement qu'on observe en hiver dans les cultures semées en automne peut se solder par des pertes importantes de rendement économique. Il est connu que les variations de la date de semis du blé d'automne blanc tendre (Triticum aestivum L.) dans l'est de l'Ontario peuvent influer à la fois sur le degré de survie à l'hiver et sur le rendement grainier. Nous avons voulu élucider les rapports existants entre les sommes de température en automne (degrés-jours de croissance), la rusticité hivernale, la tolérance à l'englacement et quelques autres caractères de la culture avec le degré de survie mesuré le printemps suivant. Les essais se déroulaient quatre années de suite (1983 à 1986) à Ottawa, 45°33′N et à Douglas (45°23′N) à 4 dates de semis soit le 27 août, le 10 et le 24 septembre et le 8 octobre. Les semis tardifs donnaient génér...

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. 1990. Effect of growing year and application of a multi-year calibration for predicting quality parameters by near infrared reflectance spectroscopy in whole-plant corn forage. Can. J. Plant Sci. 70: 747-755.Near infrared reflectance spectroscopy analysis (NIRA) to predict quality parameters in whole-plant corn forage was investigated. Quality parameters studied included acid detergent frber (ADF), in vitro dry matter digestibility (IVDMD) and crude protein (CP). Samples ofwhole-plant corn forage were collected during three growing years (1984, 1985, 1986) Nous avons 6tudi6 1'utilit6 de la spectroscopie par r6flectance dans le proche infrarouge (NIRA) pour la pr6vision des paramdtres de qualit6 du fourrage de mais planteentidre. Les paramdtres de qualit6 incluaient la teneur en fibres au d6tergent acide (ADF), la digestibilit6 de la matibre sbche in vitro (IVDMD) et la teneur en prot6ines brutes (CP). Des 6chantillons de mais fourrage plante-entibre, dont la teneur en matidres sdchesCan.

The effect of five harvesting times on the incidence of seed-borne Fusarium spp. was examined using three spring wheat cultivars grown at two locations in eastern Ontario in 1999 and 2000. Twelve Fusarium spp. were isolated from 3831 of the 24 000 seeds, which were surface disinfected and plated onto modified potato dextrose agar. Fusarium sporotrichioides Sherb., F. graminearum Schwabe, F. poae (Peck) Wollenw., F. equiseti (Corda) Sacc., and F. avenaceum (Fr.) Sacc. were the most frequently isolated species and were isolated from 6.8, 3.7, 2.8, 1.8, and 0.6% of total seeds, respectively. The remaining species, F. acuminatum Ellis & Everh., F. crookwellense Burgess, Nelson & Toussoun, F. culmorum (W.G. Sm.) Sacc., F. oxysporum Schlecht., F. sambucinum Fuckel, F. solani (Mart.) Sacc., and F. tricinctum (Corda) Sacc., collectively infected only 0.3% of total seeds. The incidence of F. graminearum, F. sporotrichioides, and total Fusarium spp. increased about twofold, from 1.7, 3.9, and 9.5% in seed harvested very early to 5.5, 8.7 , and 19.8%, respectively, after delayed harvest. Also, F. poae had a significantly lower incidence at very early and early harvest times compared to normal or later harvest dates. Incidence of total other Fusarium spp., percentage of fusarium damaged kernels (FDK), and deoxynivalenol (DON) concentration were relatively low in the harvested grain and not affected by harvesting time. Of the three cultivars used, AC Barrie had the lowest incidence of Fusarium spp., FDK, and DON concentration in the grain; Quantum was intermediate; and Celtic had the highest. Variations in the incidence of Fusarium spp. for location and year were observed and likely related to levels of inoculum and weather conditions before and during harvesting times. Key words: Wheat, grain quality, farinograph, protein concentration, N management, cultivar selection and marketing