Identification of molecular markers for aluminium tolerance in diploid oat through comparative mapping and QTL analysis.

The degree of aluminium tolerance varies widely across cereal species, with oats (Avena spp.) being among the most tolerant. The objective of this study was to identify molecular markers linked to aluminium tolerance in the diploid oat A. strigosa. Restriction fragment length polymorphism markers were tested in regions where comparative mapping indicated the potential for orthologous quantitative trait loci (QTL) for aluminium tolerance in other grass species. Amplified fragment length polymorphism (AFLP) and sequence-characterized amplified region (SCAR) markers were used to provide additional coverage of the genome. Four QTL were identified. The largest QTL explained 39% of the variation and is possibly orthologous to the major gene found in the Triticeae as well as Alm1 in maize and a minor gene in rice. A second QTL may be orthologous to the Alm2 gene in maize. Two other QTL were associated with anonymous markers. Together, these QTL accounted for 55% of the variation. A SCAR marker linked to the major QTL identified in this study could be used to introgress the aluminium tolerance trait from A. strigosa into cultivated oat germplasm.

Growth performance, carcass and pork quality of finisher pigs fed oat-based diets containing different levels of beta-glucans.

A study was undertaken to investigate the growth performance and carcass and meat quality of pigs (BW = 52 to 108 kg) fed oat-based (Avena sativa L.) diets containing four levels of mixed-linkage (1 --> 3), (1 --> 4)-beta-D-glucans. One hundred sixty pigs-80 barrows and 80 gilts (average starting BW = 52.7 kg)--were allocated to one of five diets: a wheat-barley-based control diet and four experimental diets. The groats of Marion, a covered oat, and OT789, a hulless oat, were used to formulate four isonitrogenous and isocaloric diets to achieve 4.1,3.3, 2.1, or 1.6% total /beta-glucans (as fed). Growth performance (daily gain and gain to feed ratio) was not affected (P > 0.05) by the different levels of beta-glucans. Carcass yield, although lower (P < or = 0.05) for pigs fed the control diet, was similar (P > 0.05) for pigs fed any of the experimental diets. Cutout yields were also alike (P > 0.05) across the five diets. Beta-glucan content had no effect (P > 0.05) on the longissimus muscle area, or, by and large, on the proportions of commercial cuts; the only exceptions were a commercial picnic from pigs fed the 2.1% diet lower (P < 0.05) relative to all other diets and a lower (P < 0.5) commercial loin from pigs fed diets 4.1 or 3.3% relative to the control diet. Furthermore, the relative proportions oftotal lean, total bone, and total dissectable fat in the four lean cuts (picnic, butt, loin, and ham) were not different (P > 0.05) among the five diets. For pigs fed 4.1% beta-glucans, the proportion of lean in each of the four major cuts was lower (P < 0.05). No differences (P > 0.05) associated with the level of beta-glucans were detected for either the initial or ultimate pH mean values, the subjective assessment of color or structure of the longissimus muscle, or the instrumentally measured color (L value). Similarly, drip loss was not influenced (P > 0.05) by the level of beta-glucans in the diets. Soluble protein did differ (P < 0.05) among the high- to low-beta-glucans diets. No differences (P > 0.05) associated with diets were found for fat hardness and shear values of grilled pork chops. Chemical fat of the longissimus muscle from pigs fed 4.1, 3.3, or 2.1% beta-glucans was lower (P < 0.05) compared to pigs fed the control or 1.6% beta-glucans diets. In summary, no evidence of detrimental effect of beta-glucans in oat-based diets, particularly at levels below 4%, was detected, lending support for the inclusion of oat into finisher diets.

Effect of population structure on protein-yield improvements in spring wheat (Triticum aestivum L. em Thell).

In a study designed to develop a more efficient breeding method for concurrent protein-yield improvements in wheat (Triticum aestivum L. em. Thell), 7 base populations [2 F2's, 1 intermated F2 (IF2) and 4 partial backcross (PBC) populations] developed from biparental crosses involving 2 Canadian hard red spring (CHRS) and 2 Canadian utility (CU) wheat cultivars were evaluated in Winnipeg, Manitoba, Canada. The IF2 and PBC populations were generated for comparison with conventional F2 populations and to determine which of the 4 methods of population development would provide a more efficient means of producing potentially superior genetic recombinants. Parameters pertaining to means, variances, correlations, heritabilities and frequencies of desirable and undesirable progenies were used to evaluate the limitations to genetic gain that may be expected from selection for GY and GPC in F2, IF2, CHRS-PBC and CU-PBC populations. Analysis of protein and yield data from 105 S1 lines derived from each of the 7 populations showed the CU-PBC's to have the highest grain yield (GY) and the lowest grain protein concentration (GPC) means; and the CHRS-PBC's, the lowest GY and the highest GPC means. The F2 and IF2 populations were intermediate for both characteristics. Populations developed from the same biparental cross did not differ significantly with respect to the majority of genetic parameters. However, desirable progenies combining high GY with high GPC were more frequent in the CU-PBC, and least frequent in the CHRS-PBC populations. The observed superiority of the CU-PBC populations appeared to be related to the advantage the system has in preserving the genetic integrity of a proven cultivar, while adding desirable genetic factors from another cultivar, thus capitalizing on introgression and upgrading simultaneously.