AAC Richard Soybean

AAC Richard is a food grade soybean [Glycine max (L.) Merr] cultivar with yellow hilum, high protein concentration, and good processing quality for foreign and domestic soymilk, tofu, and miso markets. It has resistance to SCN (soybean cyst nematode) (Heterodera Glycines Ichinohe). AAC Richard was developed at the Agriculture and Agri-Food Canada (AAFC) Harrow Research and Development Centre (Harrow-RDC), Harrow, Ontario and is adapted to areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity of 2.3 (MG 2.3).

Fluorescent Soybean Hairy Root Construction and Its Application in the Soybean—Nematode Interaction: An Investigation

Background: The yield of soybean is limited by the soybean cyst nematode (SCN, Heterodera glycines). Soybean transformation plays a key role in gene function research but the stable genetic transformation of soybean usually takes half a year. Methods: Here, we constructed a vector, pNI-GmUbi, in an Agrobacterium rhizogenes-mediated soybean hypocotyl transformation to induce fluorescent hairy roots (FHRs). Results: We describe the operation of FHR-SCN, a fast, efficient and visual operation pathosystem to study the gene functions in the soybean-SCN interaction. With this method, FHRs were detected after 25 days in 4 cultivars (Williams 82, Zhonghuang 13, Huipizhiheidou and Peking) and at least 66.67% of the composite plants could be used to inoculate SCNs. The demographics of the SCN could be started 12 days post-SCN inoculation. Further, GmHS1pro-1 was overexpressed in the FHRs and GmHS1pro-1 provided an additional resistance in Williams 82. In addition, we found that jasmonic acid and JA-Ile increased in the transgenic soybean, implying that the resistance was mainly caused by affecting the content of JA and JA-Ile. Conclusions: In this study, we established a pathosystem, FHR-SCN, to verify the functional genes in soybeans and the SCN interaction. We also verified that GmHS1pro-1 provides additional resistance in both FHRs and transgenic soybeans, and the resistance may be caused by an increase in JA and JA-Ile contents.

Breeding a Soybean Cultivar Heinong 531 with Peking-Type Cyst Nematode Resistance, Enhanced Yield and High Seed-Oil Contents

Soybean cyst nematode (SCN) is a destructive threat to soybean production. It’s of economic importance to develop a new SCN-resistant soybean cultivar with high yield and other good agronomic traits. In this study, a yellow-seed-coated and yellow-hilum-pigmented cultivar Heinong 531 belonging to maturity group I was developed by a pedigree breeding method through a testcross between a female parental SCN-resistant soybean cultivar Pengdou 158 and a male parental line F1 (high-yield but SCN-susceptible Hefeng 55 x SCN-resistant Kangxian 12). Heinong 531 was evaluated for SCN resistance in both SCN-infested field and autoclaved soil inoculated with hatched second-stage juveniles of SCN HG Type 0. The results indicated that SCN development at all stages in Heinong 531 was suppressed and the female index was only 1.6-5.6%. Heinong 531 as well as Pengdou 158 and Kangxian 12 were identified to carry the Peking-type resistance with both rhg1-a GmSNAP18 and Rhg4 GmSHMT08 genes. In the two-year regional trials, the average yield of Heinong 531 reached 2805.0 Kg/ha and the one-year production trial demonstrated an average yield of 2751.5 Kg/ha with yield increase of over 12.0% when compared to the local cultivars. The average seed-fat (oil) contents of Heinong 531 reached up to 22.3%. The Peking-type SCN-resistant Heilong 531 cultivar with enhanced yield and high seed-oil contents was just released in China in June, 2021 with certified number of ‘Heishendou 20210004’. These good agronomic traits make Heinong 531 prospective in a wide extension to control SCN in the main soybean-producing areas of Northeast China.

Assessing direct and residual effects of cover crops on the soybean cyst nematode, Heterodera glycines

Greenhouse experiments were conducted to determine if cover crops directly decrease population densities of the soybean cyst nematode (SCN), Heterodera glycines, and/or have residual effects on reproduction of the nematode on soybean (Glycine max). Population densities of SCN were not significantly decreased by nine cover crop plants or three cover crop mixes compared to a non-planted soil control in a repeated 60-day-long greenhouse experiment. When susceptible soybeans were grown in the soils after cover crop growth, fewer SCN females formed following three annual ryegrass (Lolium multiflorum) cultivars (Bounty, King, and RootMax), the Daikon radish (Raphanus sativus var. longipinnatus) cultivar CCS779, Kodiak mustard (Brassica juncea), and a mix containing cereal rye, crimson clover (Trifolium incarnatum), plus Daikon radish (cultivars not stated) compared to following the non-planted control. In another repeated experiment, cover crops were grown for 56 days in SCN-infested soil in the greenhouse then exposed to Iowa winter conditions for 28 days to simulate winter termination of the plants. One treatment, a cover crop mix containing Bounty annual ryegrass plus Enricher Daikon radish, had a decrease in SCN population density greater than the non-planted control at the end of the experiment. Significantly fewer SCN females formed on soybeans grown following several cover crops, including the three annual ryegrass cultivars that had the suppressive residual effects in the first experiment. In summary, there were no cover crop treatments that consistently decreased SCN population densities across experiments, and only one cover crop treatment in one experiment significantly reduced SCN population densities more than a non-planted soil control. However, there was a somewhat consistent, adverse, residual effect of cover crops on reproduction of SCN on susceptible soybeans following growth of multiple cover crops.

Development of a Species-Specific SCAR-PCR Assay for Direct Detection of Sugar Beet Cyst Nematode (Heterodera schachtii) from Infected Roots and Soil Samples

Sugar beet cyst nematode (SBCN, Heterodera schachtii) is an important nematode that causes significant yield losses of 25–50% or more in most areas of sugar beet production worldwide. Rapid and accurate identification of this species is essential to support decisions on pest management. However, the difference between H. schachtii and other Heterodera spp. based on morphology is a challenging task. In the present study, a SCAR-PCR assay was developed to identify and differentiate H. schachtii in infected root and soil samples. H. schachtii-species-specific SCAR-PCR primers OPA06-HsF and OPA06-HsR were designed from the randomly amplified polymorphic DNA (RAPD) marker amplified with random primer OPA06. The developed primers specifically amplify a 922-bp fragment from the target populations but did not amplify DNA from non-target cyst nematodes including Heterodera, Globodera, Cactodera, and other related species tested in this study. The sensitivity detection indicated that 5 × 10−4 of a single cyst, 1/320 of a single second-stage juvenile (J2), or 10 pg of genomic DNA could be detected. The assay accurately identifies the different stages of H. schachtii in sugar beet and oilseed rape roots as well as a single J2 in 10 g of soil. Finally, the SCAR-PCR assay detected H. schachtii in seven samples out of the fifteen field samples. The assay will not only be useful for differentiating H. schachtii from mixed populations of Heterodera spp. but also for effective detection of the species directly from infested samples. The assay also requires no expertise in the taxonomy and morphology of the species but serves to improve the diagnosis of H. schachtii in infested fields.