Currently recommended isolation distances of 3 or 10 m for pedigreed seed production of spring wheat (Triticum aestivum L.) may not be sufficient for cultivars with high out‐crossing (OC) rates. The detection of higher than expected OC rates in wheat has directed this research to reassess currently recommended minimum isolation distances. The objective of this study was to determine if increased isolation distances are needed for cultivars that exhibit higher than normal levels of out‐crossing. In each of 2 yr, OC rates were determined for four Canadian spring wheat cultivars at each of 15 distances (0–33 m) from a blue aleurone pollen source. Cultivars were grown in rows perpendicular to the pollinator block to the north, south, west, and east. Target rows were replicated four times within each direction. Out‐crossing in ‘Katepwa’ and ‘Biggar’ was not detected beyond 3 m. Cultivars ‘Roblin’ and ‘Oslo’ exhibited higher than normal OC at distances of up to 27 m. For Roblin and Oslo, an isolation distance of 30 m is recommended to mitigate OC‐derived off‐types in the subsequent generation of pedigreed seed.

2003). These factors vary with genotype and environment (de Vries, 1971(de Vries, , 1972(de Vries, , 1974. In wheat (Triticum L.), large-scale field studies were conductedThe occurrence of intra-and interspecific gene flow to assess the level of intra-and interspecific pollen-mediated gene in wheat and the tendency for some cultivars to possess movement that may exist at varying distances from a pollinator source.higher gene flow rates than others is well established.The objectives of this research were to measure gene flow rates from a blue-grained pollinator (T. aestivum cv. Purendo-38) to (i) red-Wheat is a predominantly self-pollinating crop with a grained spring wheat cv. CDC Teal (T. aestivum) over distances of gene-flow rate of usually less than 1% (Johnson and 0.2 to 160 m, (ii) amber durum wheat cv. AC Navigator (T. turgidum Schmidt, 1968). Heyne and Smith (1967) reported that L.) over distances of 0.2 to 260 m, and (iii) CDC Teal and AC Navigathe extent of gene flow in commercial wheat cultivars tor over distances of 180 to 2760 m. In 2000 and 2001, 50-by 50-m ranged from 0 to 4% in close proximity. Higher gene blue-grained pollinator blocks were sown and surrounded by recipient flow rates including 0.1 to 5.6% (Martin, 1990) and 0.3 fields of either CDC Teal or AC Navigator at Saskatoon, SK. At to 6.1% (Hucl, 1996) have been reported in wheat with maturity, 0.5-by 4-m strips were harvested at specified distances plants grown in close proximity. A number of studies between 0.2 and 160 m or 260 m along eight transects (N, E, S, W, have observed off-types in wheat cultivars attributable NE, SE, SW, NW) radiating out from Purendo-38. In addition, random to gene flow between wheat genotypes of the same sampling was conducted in 2000 and 2001 from surrounding wheat fields to estimate gene flow rates over distances of 180 to 2760 m. species (Appleyard et al., 1979; Porter et al., 1980; Grif-Gene flow from Purendo-38 to recipient plants was identified by the fin, 1987; Takahasi and Isii, 1988). Interspecific gene expression of a light-blue pigment in the aleurone layer of F 1 hybrid flow rates have been studied to a limited extent. Zorunseed. Confirmed intra-and interspecific pollen-mediated gene flow Ko et al. (1996) reported interspecific gene flow rates rates remained below 0.5% and declined rapidly with distance from of 0.04 to 0.30% from common hexaploid (T. aestivum; the pollinator. Elevated gene flow rates to the N, W, and NW of the 2n ϭ 6x ϭ 42 chromosomes; BBAADD) to durum wheat pollinator were associated with prevalent winds in 2000, but not in (T. turgidum; 2n ϭ 4x ϭ 28 chromosomes; BBAA), with 2001. In 2000, long distance intraspecific gene flow was confirmed at plants grown in close proximity. Research has indicated a frequency of 0.005% at a position 300 m northwest of the pollinator.that low male fertility is generally associated with culti-No evidence of interspecific gene flow was observed at Ն40 m from vars possessing higher gene-flow rates (Hucl, 1996; Inthe pollinator. The results suggest...

In plants, the C-repeat binding factors (Cbfs) are believed to regulate low-temperature (LT) tolerance. However, most functional studies of Cbfs have focused on characterizing expression after an LT shock and have not quantiWed diVerences associated with variable temperature induction or the rate of response to LT treatment. In the Triticeae, rye (Secale cereale L.) is one of the most LT-tolerant species, and is an excellent model to study and compare Cbf LT induction and expression proWles. Here, we report the isolation of rye Cbf genes (ScCbfs) and compare their expression levels in springand winter-habit rye cultivars and their orthologs in two winter-habit wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) cultivars. Eleven ScCbfs were isolated spanning all four major phylogenetic groups. Nine of the ScCbfs mapped to 5RL and one to chromosome 2R. Cbf expression levels were variable, with stronger expression in winter-versus spring-habit rye cultivars but no clear relationship with cultivar diVerences in LT, down-stream cold-regulated gene expression and Cbf expression were detected. Some Cbfs were expressed only at warmer acclimation temperatures in all three species and their expression was repressed at the end of an 8-h dark period at warmer temperatures, which may reXect a temperature-dependent, light-regulated diurnal response. Our work indicates that Cbf expression is regulated by complex genotype by time by inductiontemperature interactions, emphasizing that sample timing, induction-temperature and light-related factors must receive greater consideration in future studies involving functional characterization of LT-induced genes in cereals.

CWRS cultivars in western Canada (Saskatchewan Agriculture, Food, and Rural Revitalization, 2003) are An increasing number of western Canadian hard red spring wheat described as PI (CDC Teal, Hughes and Hucl, 1993; cultivars (Triticum aestivum L.) are photoperiod insensitive, in part, AC Eatonia, de Pauw et al., 1994; AC Elsa, Clarke et to accommodate short day winter nurseries within breeding programs. The objective of this study was to compare the agronomic performance al., 1997; AC Intrepid, de Pauw et al., 1999; AC Abbey, of near-isogenic photoperiod sensitive (PS) and insensitive (PI) hard de Pauw et al., 2000). Photoperiod response is of interest red spring wheat lines over 21 environments (1996)(1997)(1998) to determine to plant breeders in northern latitudes as PS cultivars if insensitivity had an effect on agronomic performance. Eight PS have provided good yield stability, local adaptation, and and eight PI isogenic lines within each of three genetic backgrounds high productivity in northern areas of North America including AC Minto, CDC Makwa, and SWP5304 were evaluated. (Busch et al., 1984; Knott, 1986). Photoperiod types The dominant allele Ppd-D1 conferred insensitivity to PI lines. The are classified as PS, which require long days for timely experimental design was a randomized complete block design with flowering, or PI, which can be grown successfully in three replications. Testing environments included Fort Vermillion, long or short day environments. Scarth and Law (1984) AB (58؇ N), Dawson Creek, BC (55؇ N), Saskatoon, SK (52؇ N), Elrose, reported that three genes control photoperiod in wheat SK (51؇ N), Elgin, MB (49؇ N), Bozeman, MT (45؇ N), Ste. Foy, QC (46؇ N), Charlottetown, PE (46؇ N), Guelph, ON (43؇ N), and Akron, including Ppd-D1 located on the long arm of chromo-CO (40؇ N). Measurements were made on 11 traits including final leaf some 2D, Ppd-B1 on the short arm of 2B, and Ppd-A1 number, days to heading and maturity, plant height, grain yield, kernel located on the long arm of 2A. The dominant alleles weight, spikelets per spike (total, fertile, and sterile), seeds per spike, Ppd-A1, Ppd-B1, and Ppd-D1 (formerly Ppd3, Ppd2, and yield per spike. Generally, PS lines were later in heading andand Ppd1, respectively) confer insensitivity to photopematurity, taller, initiated more leaves and spikelet primordia, and 5% riod whereas the recessive alleles (ppd-A1, ppd-B1, and higher yielding. Genetic backgrounds differed significantly in all traits, ppd-D1; formerly ppd3, ppd2, and ppd1, respectively) except final leaf number and grain yield. Significant, noncrossover, confer sensitivity. The potency of the group 2 photopephotoperiod response type ϫ genetic background interactions were riod genes for insensitivity has been ranked in the order observed only for fertile spikelets per spike and seeds per spike. Our Ppd-D1 Ͼ Ppd-B1 Ͼ Ppd-A1 (Worland, 1996).

Pre-harvest sprouting (PHS) in developing wheat (Triticum aestivum L.) spikes is stimulated by cool and wet weather and leads to a decline in grain quality. A low level of harvest-time seed dormancy is a major factor for PHS, which generally is a larger problem in white-grained as compared to red-grained wheat. We have in this study analyzed seed dormancy levels at the 92nd Zadok growth stage of spike development in a doubled-haploid (DH) white wheat population and associated variation for the trait with regions on the wheat genome. The phenotypic data was generated by growing the parent lines Argent (non-dormant) and W98616 (dormant) and 151 lines of the DH population in the field during 2002 and 2003, at two locations each year, followed by assessment of harvest-time seed dormancy by germination tests. A genetic map of 2681 cM was constructed for the population upon genotyping 90 DH lines using 361 SSR, 292 AFLP, 252 DArT and 10 EST markers. Single marker analysis of the 90 genotyped lines associated regions on chromosomes 1A, 2B, 3A, 4A, 5B, 6B, and 7A with seed dormancy in at least two out of the four trials. All seven putative quantitative trait loci (QTLs) were contributed by alleles of the dormant parent, W98616. The strongest QTLs positioned on chromosomes 1A, 3A, 4A and 7A were confirmed by interval mapping and markers at these loci have potential use in marker-assisted selection of PHS resistant white-grained wheat.

lightness in CWWS cultivars will depend, in part, on the existence of genetic variation for grain color. To Improvement of grain color in hard white spring wheat (Triticum date, little information is available on the presence of aestivum L.) breeding programs depends on understanding the influgenetic variability for grain color in HW spring wheat. ences of genotype (G), environment (E), and their interaction (G ϫ E). The objectives of this study were to quantify genetic variability Red kernel color is controlled by up to three loci, for grain color and assess the nature of the G ϫ E interaction in located on chromosomes of homologous Group 3, with determining grain color in 79 spring wheat genotypes. Twelve check partial dominance over white kernel color (Metzger and cultivars [seven hard red (HR), four hard white (HW), and one soft Silbaugh, 1970). In addition to three major loci controlwhite (SW)] and 67 white-seeded Australian (AUS) accessions were ling red seed color, there may be as many as six minor grown at two locations across 2 yr. Wheat genotypes differed signifigenes influencing grain color (Freed et al., 1976; Reitan cantly in agronomic traits, grain protein, and kernel hardness. Grain 1980). Kernel color is known to be a highly heritable and meal color were quantified using Hunterlab colorimeter values. trait (Cooper and Sorrells, 1984); however, color is known Whole grain color values without (L ϭ 40.9-50.4 units; a ϭ 7.0-8.3; to vary in its degree of lightness across environments. b ϭ 13.6-19.1) and with NaOH treatment (L ϭ 22.7-38.1; a ϭ 7.7-9.7; b ϭ 9.2-17.9) varied among genotypes. Using ground meal, color Wu et al. (1987) reported that kernel color of white values (L ϭ 80.1-84.9; a ϭ 1.8-2.6; b ϭ 8.9-11.8), yellow pigment wheat cultivars from northern China was darker when content (2.5-4.8 g g Ϫ1 ), and lutein content (1.8-3.7 g g Ϫ1 ) varied grown in the more humid region of the Lower Yangtze among genotypes. Genotype ϫ location (L) interactions were not Valley. Wu et al. (1999) reported that some HW winter significant for colorimetric and pigmentation variables. The Azallini experimental lines were found to be more sensitive to and Cox test detected one crossover G ϫ year (Y) interaction for environmental changes than HR winter check cultivars, grain a-value (without NaOH), one for grain b-value (without NaOH), but others were found with improved levels of color and 12 for lutein content. Genetic variation exists for grain color and color stability across environments when compared among HW genotypes. The noncrossover nature of G ϫ E interactions for grain color indicates that white-seeded genotypes selected as supe-with HW winter check cultivars. Peterson et al. (2001) rior in one environment will be superior in other environments.documented variation in grain color in white winter wheat across an array of production environments and cultivars. Only one of 18 HW cultivars grown at five

Wheat (Triticum aestivum L.) is a self-pollinated species with outcrossing (OC) rates assumed to be less than 1%. The objective of this study was to evaluate the OC rates for 35 Canadian spring wheat cultivars grown under greenhouse conditions. Recipient cultivars were crossed with Purendo-38, a blue aleurone wheat, using direct spike contact inside glassine bags. Four seeding dates were used in each of two greenhouse experiments (2001 and 2002). Out-crossing rates ranged from 0 to 2.8% (2001) and 0 to 3.5% (2002), with the exception of 'Glenlea' and 'Wildcat'. Only Glenlea (10.6% [2001]; 8.6% [2002]) and Wildcat (6.3% [2001]; 4.2% [2002]) displayed consistently elevated levels of OC.

Currently, information is lacking on gene flow in common wheat (Triticum aestivum L.) at distances greater than 300 m based on commercial‐scale fields. The objective of this research was to measure pollen‐mediated gene flow rates from a blue‐aleuroned pollinator (T. aestivum cv. ‘Purendo‐38’) to neighboring commercial fields of common wheat grown within a 10‐km radius of a central pollinator field. In the 2‐yr study, 33‐ha (2002) and 20‐ha (2003) fields of Purendo‐38 were sown 200 km east‐northeast of Saskatoon, Saskatchewan. Sixty‐nine fields in 2002 and 76 fields in 2003 were identified as having overlapping flowering relative to Purendo‐38. At maturity, up to 2 m2 samples were harvested from each corner of each recipient field. Gene flow was identified by the expression of a light‐blue pigment in the aleurone layer of F1 hybrid seed. In 2002 one case of gene flow was confirmed at 190 m northeast of the pollinator at a rate of 0.01%. In 2003 nine putative hybrid seeds were confirmed to be the result of gene flow between Purendo‐38 and the recipient field using gliadin fingerprinting. Consequently, gene flow was confirmed at 0.01% at 500 m northeast, 630 m southeast, and 2.75 km northwest from the pollinator. In commercial production, gene flow in wheat occurs at trace levels (≤ 0.01%) at distances up to 2.75 km.