Agriculture and Agri-Food Canada

About: Agriculture and Agri-Food Canada is a facility organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Soil water. The organization has 10921 authors who have published 21332 publications receiving 748193 citations. The organization is also known as: Department of Agriculture and Agri-Food.

Selection response in subdivided target regions

Abstract: In a small target region, it may be possible to exploit local adaptation to increase gains from selection. However, in a large region more extensive testing is usually possible, resulting in more precise estimation of genotype means. A correlated response model was adapted to determine if division of a large target region is likely to increase gains. Genotypic value in a large region and constituent subregions are considered correlated traits. Correlated response in a subregion to indirect selection across the undivided region, relative to direct response to selection within the subregion, is expressed as a function of heritability in the undivided region (H) and in the subregion (H(i)), and of the genotypic correlation between region and subregion means (r(G'). r(G') depends on the magnitude of the genotype x subregion interaction (sigma2GS)) relative to the genotypic variance (sigma2(G)). sigma2(GS) is the portion of the genotype x location interaction (sigma2(GL)) caused by local adaptation, rather than by random site-to-site variability in genotype means. Subdivision can increase heritability through the addition of sigma2(GS) to the numerator of H(i), but this may be offset by reduced replication across locations within the subregion. Modeling using variance estimates from several cereal programs indicated that, unless sigma2(GL) is large relative to sigma2(G) and at least 30% of sigma2(GL) is due to sigma2(GS), subdivision is unlikely to increase response. These results help explain the success of breeding programs that test broadly.

Precipitation Trends on the Canadian Prairies

Abstract: The Canadian prairies are a major producer of grain, much of which is produced under rain-fed agriculture. The amount and timing of precipitation are critical to grain production. Information on the precipitation trend is therefore vital to this region. Regression analysis was used to establish linear trends of precipitation amounts, number of precipitation events, and variance of precipitation at 37 stations with 75 yr of record across the Canadian prairies. The precipitation was further split into rainfall and snowfall, and similar analysis was performed on these variables. The analysis showed that there has been a significant increase in the number of precipitation events mainly due to an increase in the number of low-intensity events. As such, precipitation events are not getting more intense on the Canadian prairies. The number of precipitation events (excluding events that are 0.5 mm or less) has increased by 16 events during the last 75 yr. Precipitation and rainfall amounts have increased...

Genomic constitution and variation in five partial amphiploids of wheat–Thinopyrum intermedium as revealed by GISH, multicolor GISH and seed storage protein analysis

Abstract: Genomic in situ hybridization (GISH) and multicolor GISH (mcGISH) methodology were used to establish the cytogenetic constitution of five partial amphiploid lines obtained from wheat × Thinopyrum intermedium hybridizations. Line Zhong 1, 2n=52, contained 14 chromosomes from each of the wheat genomes plus ten Th. intermedium chromosomes, with one pair of A-genome chromosomes having a Th. intermedium chromosomal segment translocated to the short arm. Line Zhong 2, 2n=54, had intact ABD wheat genome chromosomes plus 12 Th. intermedium chromosomes. The multicolor GISH results, using different fluorochrome labeled Th. intermedium and the various diploid wheat genomic DNAs as probes, indicated that both Zhong 1 and Zhong 2 contained one pair of Th. intermedium chromosomes with a significant homology to the wheat D genome. High-molecular-weight (HMW) glutenin and gliadin analysis revealed that Zhong 1 and Zhong 2 had identical banding patterns that contained all of the wheat bands and a specific HMW band from Th. intermedium. Zhong 1 and Zhong 2 had good HMW subunits for wheat breeding. Zhong 3 and Zhong 5, both 2n=56, possessed no gross chromosomal aberrations or translocations that were detectable at the GISH level. Zhong 4 also had a chromosome number of 2n=56 and contained the complete wheat ABD-genome chromosomes plus 14 Th. intermedium chromosomes, with one pair of Th. intermedium chromosomes being markedly smaller. Multicolor GISH results indicated that Zhong 4 also contained two pairs of reciprocally translocated chromosomes involving the A and D genomes. Zhong 3, Zhong 4 and Zhong 5 contained a specific gliadin band from Th. intermedium. Based on the above data, it was concluded that inter-genomic transfer of chromosomal segments and/or sequence introgression had occurred in these newly synthesized partial amphiploids despite their diploid-like meiotic behavior and disomic inheritance.