Brian L. Beres

Weed-competitive ability of spring and winter cereals in the northern Great Plains.

Abstract The inclusion of winter cereals in spring-annual rotations in the northern Great Plains may reduce weed populations and herbicide requirements. A broad range of spring and winter cereals were compared for ability to suppress weeds and maximize grain yield at Lacombe (2002 to 2005) and Lethbridge (2003 to 2005), Alberta, Canada. High seeding rates (≥ 400 seeds/m2) were used in all years to maximize crop competitive ability. Spring cereals achieved high crop-plant densities (> 250 plants/m2) at most sites, but winter cereals had lower plant densities due to winterkill, particularly at Lethbridge in 2004. All winter cereals and spring barley were highly effective at reducing weed biomass at Lacombe for the first 3 yr of the study. Weed suppression was less consistently affected by winter cereals in the last year at Lacombe and at Lethbridge, primarily due to poor winter survival. Grain yields were highest for spring triticale and least for spring wheat at Lacombe, with winter cereals intermediate. At Lethbridge, winter cereals had higher grain yields in 2003 whereas spring cereals had higher yields in 2004 and 2005. Winter cereals were generally more effective at suppressing weed growth than spring cereals if a good crop stand was established, but overlap in weed-competitive ability among cultivars was considerable. This information will be used to enhance the sustainable production of winter and spring cereals in traditional and nontraditional agro-ecological zones.

Biology and Integrated Management of Wheat Stem Sawfly and the Need for Continuing Research

Abstract The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is historically one of the most important economic insect pests in the northern Great Plains of North America. Within this geographical region, the areas subjected to greatest attack are southern Alberta and Saskatchewan, southwestern Manitoba, eastern and northern Montana, North Dakota, northern South Dakota, and western Minnesota. Cumulative grain-yield losses and annual economic losses associated with this pest can exceed 30% and

Influence of plant host quality on fitness and sex ratio of the wheat stem sawfly (Hymenoptera: Cephidae)

350 million, respectively. Solid-stemmed cultivars of common wheat, Triticum aestivum L. (Poaceae), tolerant of infestation, are critical for C. cinctus management, but outbreaks of this pest continue to occur even after six decades of cultivar development. Furthermore, chemical control (a primary control option for other cereal (Poaceae) insect pests) has proven ineffective; this underscores the need to integrate resistant cultivars into a comprehensive integrated pest management program. We provide overviews of wheat stem sawfly biology, recent advances in applied research, the efficacy and integration of cultural and biological management strategies, and future directions for global research activities to manage wheat stem sawfly.

Evaluation of crossability between triticale (X Triticosecale Wittmack) and common wheat, durum wheat and rye

Abstract A resurgence of the wheat stem sawfly, historically the most important pest of wheat in the northern Great Plains, has been observed in western Canada over the past decade. Host plant resistance in the form of solid-stemmed cultivars remains the primary management strategy for this pest. The objectives of this study were to determine the effects of wheat cultivar on wheat stem sawfly fitness and sex ratio. The cultivars studied varied with respect to stem diameter and pith expression and included representatives of the red seed, solid-stemmed spring and red seed, hollow-stemmed common and durum wheat classes. We present results from a primary study conducted in southern Alberta from 2001 to 2003 and a similar smaller study conducted in 1987 and 1991. All of the solid-stemmed cultivars (AC Eatonia, AC Abbey, Lancer, Leader) reduced female weights, size, fecundity, and in some cases, larval survivorship in the cut stubs and delayed date of adult emergence in the laboratory. Males were less responsive to this aspect of host quality. The hollow-stemmed durum cultivar AC Navigator had similar negative effects and deserves further study. A number of other hollow-stemmed wheats (McKenzie, AC Intrepid, Katepwa, and the durum AC Avonlea) had intermediate but inconsistent negative effects on sawfly fitness. The varieties that maximized sawfly fitness were AC Cadillac, CDC Teal, and Kyle (durum). Sawfly sex ratios were affected by stub diameter in our current and historical cultivar studies. Larger diameter stubs produced significantly more females and smaller diameter stubs produced more males. Furthermore, stubs that failed to produce adults had significantly smaller diameters than those that produced females but similar to those that produced males. The effect of the solid stem trait on sex ratio was inconsistent. Only Lancer had a male-biased sex ratio, whereas the other varieties had no consistent pattern. These results, however, are similar to other published reports that have noted inconsistent effects of the solid trait on sex ratio. Planting a solid-stemmed cultivar in a rotation that includes broad-leaved crops is recommended to reduce sawfly damage and future populations.

Developmental instability in a stem-mining sawfly: can fluctuating asymmetry detect plant host stress in a model system?

Development of transgenic triticale as a platform for novel bio-industrial products is predicated on an environmental biosafety assessment that quantifies the potential risks associated with its release. Pollen-mediated gene flow to related species and conventional triticale varieties is one pathway for transgene movement. A tier 1 quantification of triticale hybridization was conducted by emasculating and hand pollinating flowers under greenhouse conditions. Approximately 2000 manual pollinations were conducted for each cross and its reciprocal between two triticale genotypes: a modern triticale cultivar (AC Alta) and primary triticale (89TT108), and common wheat, durum wheat and rye. The frequency of outcrossing, hybrid seed appearance and weight, and F(1) emergence and fertility were recorded. Outcrossing, F(1) emergence and fertility rates were high from crosses between triticale genotypes. Outcrossing in inter-specific crosses was influenced by the species, and the genotype and gender of the triticale parent. In crosses to common and durum wheat where triticale was the male parent, outcrossing was > or =73.0% and > or =69.5%, respectively, but < or =23.9% and < or =3.0% when triticale was the female parent. Overall, outcrossing with rye was lower than with common and durum wheat. F(1) hybrid emergence was greater when triticale was the female parent. With the exception of a single seed, all wheat-triticale F(1) hybrid seeds were non-viable when triticale was the male parent in the cross. Only seven durum wheat-triticale F(1) hybrids emerged from 163 seeds sown, and all were produced with triticale 89TT108 as female parent. With rye, 8 F(1) hybrids emerged from 38 seeds sown, and all were produced from crosses to AC Alta; five with AC Alta as the female parent and three as the male. Interspecific F(1) hybrids were self-sterile, with the exception of those produced in crosses between common wheat and triticale where triticale was the female parent. Tier 2 hybridization quantification will be conducted under field conditions.

Integrating the building blocks of agronomy and biocontrol into an IPM strategy for wheat stem sawfly

Fluctuating asymmetry (FA) may be a sensitive indicator of the stress experienced by organisms during their development. Its use in this manner is an intuitively appealing, frequently proposed, and potentially powerful tool but remains controversial partially because its underlying premise rarely has been critically tested. Such tests should include direct comparisons among individuals for which levels of FA, stress and fitness have been unambiguously quantified. We assessed the use of FA as a bioindicator of the stress experienced during egg-to-adult development by the stem-mining sawfly, Cephus cinctus Norton. Sawflies were reared in a common garden from seven different wheat cultivars, which were selected to represent a gradient of stem solidness, a key factor imposing stress on sawflies during development. In this model system, stress was quantified by the weight of emergent adults. Fitness was quantified by counting the number of eggs in dissected females, which emerge with their full lifetime complement. FA was measured for wing length, three wing cells, and three wing veins using image analyses. The greatest amount of stress was induced by solid-stemmed cultivars from which the adults were significantly smaller than those developing in hollow-stemmed hosts. In turn, adult weight was positively correlated with fitness. The net effect was a 25-fold variation in sawfly fitness, which gave a reasonable expectation that FA levels would differ across cultivars. However, FA levels of all the traits were similar among cultivars and there was no negative relationship between FA and fitness. These results: (1) document the failure of FA as an indicator of stress in this model system, (2) identify adult weight as a satisfactory indicator of plant-induced stress and sawfly fitness, and (3) add to the growing body of literature questioning the value of FA as a biomonitor tool of developmental stress.

Response of irrigated soft white spring wheat to seeding date, seeding rate and fertilization

Integrating the building blocks of agronomy and biocontrol into an IPM strategy for wheat stem sawfly. Brian L. Beres , Héctor A. Cárcamo, David K. Weaver, Lloyd M. Dosdall, Maya L. Evenden, Bernard D. Hill, Ross H. McKenzie, Rong-Cai Yang, and Dean M. Spaner U. of Alberta, Edmonton, Alberta, AB Agriculture and Agri-Food Canada, Lethbridge, AB Montana State University, Bozeman, MT University of Alberta, Edmonton, AB Alberta Agriculture & Rural Development, Lethbridge, AB Corresponding authors E-Mail: brian.beres@agr.gc.ca

Efficacy of high seeding rates to increase grain yield of winter wheat and winter triticale in southern Alberta

Irrigated production of soft white spring wheat (Triticum aestivum L. Em Thell.) (SWSW) for pastry flour or ethanol production is feasible if the high yield potential of recently released cultivars can be realized. Field studies were conducted at three locations over a 3-yr period to determine the response of irrigated SWSW to seeding date, seeding rate and fertilization (N, P and K) in southern Alberta. The highest yield was obtained for the first seeding date (Apr. 20 to 24). Seeding 2 wk later reduced ave rage grain yield by 3%, while seeding 4 wk later reduced average grain yield by 15%. The optimum seeding rate was 200 to 240 viable seeds m-2 (84 to 101 kg ha-1). Maximum yields were achieved when total available N (fertilizer + residual soil NO3-N + mineralized N) was greater than 26 kg N Mg-1 of potential yield. Mineralized N ranged from 45 to 183 kg N ha-1 (mean 125 kg N ha-1). Grain protein concentration did not exceed the maximum allowed for protein premiums (99 g kg-1) when total available N was...

Resistance to cabbage seedpod weevil among selected Brassicaceae germplasm

Field trials were conducted for 3 yr (2002/2003 to 2004/2005) at three locations in southern Alberta to determine the impact of seeding rate and opener type on plant stand and grain yield of winter wheat (Triticum aestivum L.) and winter triticale (× Triticosecale Wittmack). Responses were determined for an optimum date of seeding in early to mid-September and for a late seeding in early to mid-October. Conditions were generally favourable for crop establishment, winter survival and growth, and average site yields ranged from 4.5 to 8.9 Mg ha-1. The disc opener increased spring plant density by 12.5% compared with the hoe opener, but did not affect grain yield. Spring plant density was 23% lower for winter triticale than winter wheat and 20% lower for October-seeded cereals than September-seeded cereals. Late seeding reduced grain yields of winter wheat and winter triticale by an average of 18 and 11%, respectively. Increases in target seeding rates from 150 to 350 plants m-2 (approximately 70 to 160 kg h...

Influence of N fertilization method on weed growth, grain yield and grain protein concentration in no-till winter wheat.

Brassicaceae germplasm (Brassica napus L., Brassica rapa L., Brassica juncea (L.) Czern., Brassica carinata A. Braun, Sinapis alba L., Camelina sativa (L.) Crantz, Crambe species) with cultivar development potential for the prairies was evaluated for resistance to cabbage seedpod weevil (Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae)) infestation under field conditions in southern Alberta from 2001 to 2005. Relative susceptibilities were as follows: B. rapa and B. napus > B. juncea = B. carinata > S. alba. Although some of the germplasm evaluated varied within species in terms of glucosinolate profile, erucic acid level, oil content, and plant height, none of these factors appeared to influence the degree of C. obstrictus damage. A subset of this germplasm was also evaluated in the greenhouse. Although the canola species B. rapa sustained the highest level of damage in the field tests, it was similar to other Brassica genotypes in the greenhouse. All lines of S. alba were virtually immune ...