RESUMO:Com o intuito de orientar melhoristas na escolha de parentais visando à resistência à ferrugemasiática associada a características de interesse econômico, foram avaliados 17 genótipos de soja quanto às características agronômicas e moleculares por meio de marcadores microssatélites. Foram instalados dois experimentos, o primeiro inoculado com ferrugem-asiática e o segundo sem inoculação. A média de alelos por loco foi igual a 4,56, sendo verificados alelos exclusivos nas cultivares TMG 801, UFUS Impacta, UFUS Xavante, Conquista, BRSGO 7860RR, A 7002 e UFVTN 104. Por meio do índice ponderado, com base no polimorfismo molecular, verificou-se o maior valor de similaridade para as cultivares Conquista e BRS Valiosa RR. O peso médio de 100 sementes foi igual a 14,56g no experimento com ferrugem-asiática, e 18,0g no experimento sem ferrugem-asiática. As médias da proporção de lesões nos folíolos infectados por ferrugem-asiática ocorreram entre 11,48% a 47,18%. Com base nos resultados pôde-se concluir que existe substancial variabilidade genética no germoplasma da soja em relação aos alelos potencialmente ligados aos genes de resistência à ferrugem-asiática. Visando a resistência ou tolerância à ferrugem-asiática associada a características econômicas de interesse seriam mais indicados os cruzamentos das cultivares UFVTN 104 com TMG 801 e/ou UFUS Impacta, Conquista com UFUS Xavante, e UFUS 8011 com BRSGO 7560 e/ou TMG 803.

Soybean is one of the most valuable commercial crops because of its high protein, carbohydrate, and oil content. The land area cultivated with soybean in subtropical regions, such as Brazil, is continuously expanding, in some instances at the expense of carbon storing natural habitats. Strategies to decrease yield/seed losses and increase production efficiency are urgently required to meet global demand for soybean in a sustainable manner. Here, we evaluated the effectiveness of an Ascophyllum nodosum extract (ANE), SealicitTM, in increasing yields of different soybean varieties, in two geographical regions (Canada and Brazil). In addition, we investigated the potential of SealicitTM to reduce pod shattering at the trials in Brazil. Three different concentrations of SealicitTM were applied to pod shatter-susceptible (SS) UFUS 6901 and shatter-resistant (SR) UFUS 7415 varieties to assess their impact on pod firmness. SS variety demonstrated a significant decrease in pod shattering, which coincided with deregulation of GmPDH1.1 and GmSHAT1–5 expression, genes that determine pod dehiscence, and higher seed weight per pod. SealicitTM application to the SR variety did not significantly alter its inherent pod shatter resistance, but provided higher increases in seed yield at harvest. This yield increase maybe associated with to other yield components stimulated by the biostimulant. This work demonstrates that SealicitTM, which has previously been shown to improve pod firmness in Arabidopsis and selected commercial oilseed rape varieties through IND gene down-regulation, also has the potential to improve pod resistance and seed productivity in soybean, a member of the legume family sharing a similar strategy for seed dispersal.

In Brazil, as the soybean crop expands the losses caused by nematodes as well as its incidence in producing areas have increased. Therefore, this work aimed to develop a non-genetically modified soybean which combines desirable traits as the root-knot nematode resistance, early-maturity, high seed yielding, and high oil and protein contents. Consequently, seeds (F2) derived from the double-crossing between (Guarani x Sambaiba) x (M Soy 6101 x Conquista) were bulked to grow the F3 generation. Following generations were advanced by the SSD method of breeding until F6. Thus, plants showing superior characteristics were planted separately to perform progeny tests and then advanced breeding lines were thoroughly tested and compared to standards in representative environments across several locations in the Midwestern region in Brazil. As a result, we developed an early-soybean with cycle-length of 107 days; usually cycles range from 90 to 160 days. It presents desirable traits as high yield (3677 kg ha-1), Brazilian national average ranged between 2.5 and 3 thousand kg ha-1; broad adaptability, with 19% of oil, and 38.4% of protein on the seeds. Oil and protein standard contents are 20% and 40%, respectively. In addition, it is root-knot nematode (Pratylenchus brachyurus) resistance, not differing statistically (RF = 1.70) from the expected value given by Crotalaria spectabilis (RF = 1.14). Accordingly, we recommend this new cultivar to producers that intend to grow a second crop of either corn or cotton in the summer, or for crop producing areas with high incidence of P. brachyurus.

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This paper aims to present the features of the new soybean cultivar UFUS Milionária, which was developed by the Soybean Improvement Program of the Federal University of Uberlândia (UFU) through crossing between IAC-100 and Cristalina RCH cultivars, using the Single Seed Descent (SSD) method. UFUS Milionária is resistant to many diseases caused by the fungus, bacteria, and virus. In addition, it also has been proved well-adapted to many Brazilian states, showing high yield even under water deficit conditions and Asian-rust infection; average yield was 4,451 kg ha-1 in 2015/16 growing season.

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