ECODA project number: A.1
Principal investigators: David Hendrick/Jim McCullagh
Sub-activity 1.1 – Natto soybean seed size and seed yield limitation
Soyfood cultivars are selected by Asian food manufacturers for their end-use function in the production of tofu, soymilk or natto. Canadian exporters and growers are also interested in profitable production, especially improved seed yield. Natto is a fermented soybean product for producers specifically require small seeded soybean. Natto-type soybeans are highly specialized and serve niche markets. As a result, little public research and development targets natto-type soybean. Since smaller seeded soybean cultivars are lower yielding, this sub-activity investigated breeding approaches and physiological approaches to increase yield. A small x large seed cross was compared to a small x small seed cross. It was found that the small x large seed cross produced a wide range of seed sizes with somewhat higher yield. Five natto lines have been retained for further testing as potential cultivars. From physiological studies, it was found that seed yield was optimum with a seed weight of 15 grams/100 seeds. Using shading, it was found that natto soybean plants are not source (sunlight absorption) limited, that is, they did not respond differently to shades reducing sunlight compared to large seeded cultivars.
Sub-activity 1.2 – Enhancing the food grade quality of short-season soybeans in Ontario, PEI and Austria
The objective of this project was to develop new germplasm from crosses between Canadian cultivars and soybean germplasm lines and cultivars from Canada and overseas with beneficial traits for the food grade and nutraceutical markets. Every year, a number of biparental crosses were made in the growth room at the University of Guelph to produce F1 seeds that were used for the production of the breeding populations. Traits of interest under this sub-activity included high yield, high protein content, absence of lipoxygenase and modified fatty acid profiles. Single plants were selected in F4, single rows in F5 and F6 lines were selected based on preliminary yield trials in one location. The F7 and F8 lines were selected based on advanced and private yield trials. As a result of this project, a number of soybean cultivars without lipoxygenase and low linolenic acid content have been developed. Such traits improve the taste of tofu and soymilk by reducing or removing the “beany” taste that comes as result of polyunsaturated fatty acid oxidation in the soybean food products. In addition, cultivars with enhanced vitamin E content adapted to Ontario conditions as well as number of high yielding food grade cultivars have been developed and released to industry.
Tofu and natto trials were conducted on Prince Edward Island – as a new region for production of food soybean cultivars – to evaluate their performance in this environment. Several genotypes, specifically DH863 and DH710, performed well in the tofu and natto trials, respectively.
Sub-activity 1.3 – Selection of high tocopherol soybean lines
For objective 1, a multi-location replicated trial was initiated in 2011 at three sites in Eastern Canada with twenty 2800-2900 CHU cultivars or advanced selections from Sevita International. Data were collected during the 2011 and 2012 seasons and all samples were analyzed for tocopherol concentrations. At the end of the trial, all data from the six environments were analyzed using various statistical tools, including GGE genotype-by-trait biplots and mean tocopherol concentration versus coefficient of variation biplots to assess tocopherol variation and stability among genotypes evaluated. The data demonstrated that among the advanced material from Sevita International there is a large variation in α-tocopherol concentration, values ranging between 7.9 and 38.2 μg/g, representing a 382% difference in concentrations across sites and across genotypes. The variation observed for other tocopherols was smaller, being of 95, 48 and 47%, for delta-, gamma- and total tocopherol. Despite the presence of significant genotype by environment interactions for all tocopherols, the ranking of genotypes was often quite stable across environments. Genotypes with high and stable tocopherol concentrations were identified, which were HS0511H32, DH530, DH715L and DH410SCN for α-, δ-, γ- and total tocopherol.
For objective 2, correlations between 30 important agronomic, food and nutraceutical properties were calculated for 156 food grade soybean samples collected from multi-location trials in 2010, 2011 and 2012. These variables included: tocopherols, isoflavones, lutein, soyasapogenols, oil, protein, sucrose, stachyose and raffinose, fatty acid profile, seed yield, seed weight, % emergence, days to flowering, days to maturity, plant height, lodging and white mould incidence. All compositional data were analyzed using wet chemistry. There were a total of six positive and seven negative correlations for α-tocopherol, seven positive and six negative for δ-tocopherol, seven positive and ten negative for γ-tocopherol and six positive and eight negative for total tocopherol. The correlations with the highest Pearson coefficients for α-tocopherol were those with days to maturity and days to flowering (i.e. r=-0.54 and -0.50, respectively). Similar strong correlations with days to maturity were also observed for γ-tocopherol and total tocopherol (i.e. r=-0.72 and -0.52, respectively). A negative correlation was also observed between these three tocopherols and seed yield (i.e. r ranging between -0.40 and -0.64). Although some significant correlations were observed between tocopherols and some other nutraceutical traits such as isoflavones and lutein, none had a Pearson correlation coefficient greater than ±0.40. No correlation between tocopherols and other important seed traits such as protein and oil content was observed.
Sub-activity 1.4 – Development of markers for cytokinin based yields in soybeans
Seed composition can affect the function and flavour of soymilk and tofu. Breeding populations varying for protein profile, sucrose content and lipoxygenase enzymes were developed and breeding lines evaluated. One line has been retained with higher levels of sucrose, SE06-0337ML-1. The line SE06-0337ML-3 has higher hydrolysable carbohydrates, a trait useful for miso production. Lipoxygenase null lines produce soymilk with a less “beany” flavour and one lipoxygenase free line has been retained, SQ05-0026M-3lx-3. Eight lines will be further evaluated for their potential as new cultivars.