Symbiotic effectiveness of fast-growing rhizobial strains isolated from soybean nodules in Brazil

Hungría, Mariangela; Campo, R. J.; Chueire, Ligia Maria Oliveira; Grange, Luciana; Megı́as, Manuel

doi:10.1007/s003740100338

Cited by 36 publications

(2 citation statements)

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“…We did not find any positive correlation between the number of nodules per plant and %Ndfa. Although nodule number has been used as a major indicator of nitrogen fixation capacity (%Ndfa) in the literature, it has also shown limited proxy value in some studies (Hungria and Bohrer, 2000;Hungria et al, 2001;. However, in this study, nodule dry weight was positively correlated with the total shoot-N fixed.…”

Section: Traits That Predict Symbiotic Nitrogen Fixation In Ontario Soybeanmentioning

confidence: 50%

Testing Whether Pre-Pod-Fill Symbiotic Nitrogen Fixation in Soybean Is Subject to Drift or Selection Over 100 Years of Soybean Breeding

et al. 2021

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Soybean [Glycine max (L.) Merr.] is the world's leading legume crop and the largest oilseed crop. It forms a symbiotic relationship with rhizobia bacteria residing in root nodules that provide fixed nitrogen to host plants through symbiotic nitrogen fixation (SNF). In soybean, it has been widely reported that the highest SNF occurs at the pod-filling stage, associated with the peak demand for nitrogen. However, the majority of seed nitrogen is derived from remobilizing root/shoot nitrogen, representing cumulative SNF from the seedling stage to the pre-pod-fill stage. Therefore, the question arises as to whether there has also been selection for improved SNF at these earlier stages, or whether pre-pod-fill SNF traits have drifted. To test this hypothesis, in this study, pre-pod SNF-related traits were evaluated in soybean cultivars that span 100 years of breeding selection in the Canadian Province of Ontario. Specifically, we evaluated SNF traits in 19 pedigree-related historical cultivars and 25 modern cultivars derived from the University of Guelph soybean breeding program. Field trials were conducted at Woodstock, Ontario, Canada in 2016 and 2017, and various SNF-related traits were measured at pre-pod-fill stages (R1-R3), including nitrogen fixation capacity. Considerable variation was observed among Canadian soybean cultivars released over the past 100 years for pre-pod-fill nitrogen fixation. The modern soybean cultivars had similar or moderately higher pre-pod-fill SNF compared to the historical lines in terms of the percentage of nitrogen derived from the atmosphere (%Ndfa) and total shoot fixed nitrogen. These findings suggest that, despite no direct selection by breeders, pre-pod-fill nitrogen fixation, and associated SNF traits have been maintained and possibly improved in modern soybean breeding. However, the low level of pre-pod-fill SNF in some modern cultivars, and generally wide variation observed in SNF between them, suggest some level of genetic drift for this trait in some pedigrees. Specific historical and modern soybean cultivars were identified as potential parents to enable targeted breeding for improved pre-pod-fill SNF. This retrospective study sheds light on our understanding of the impact of decades of recent selective breeding on pre-pod-fill nitrogen fixation traits in soybean in a temperate environment.

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Section: Traits That Predict Symbiotic Nitrogen Fixation In Ontario Soybeanmentioning

confidence: 50%

Testing Whether Pre-Pod-Fill Symbiotic Nitrogen Fixation in Soybean Is Subject to Drift or Selection Over 100 Years of Soybean Breeding

et al. 2021

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“…A sensibilidade ao fotoperíodo, no entanto, pode modificar essa resposta, ou seja, uma planta de dia curto em condição de dias longos reduz sua taxa Assim, a germinação ideal de sementes de soja, o crescimento e o desenvolvimento, são favorecidos em temperatura em torno de 30° C. Em temperaturas menores ou iguais a 10° C a soja apresenta crescimento vegetativo pequeno ou nulo e acima de 40° C, há distúrbios na floração e prejuízo na retenção de vagens (EMBRAPA, 2010). Ainda, a indução da floração ocorre em temperaturas acima de 13° C. Em relação à fixação biológica de nitrogênio, a maior nodulação ocorre em temperaturas em torno de 27° C, sendo altas temperaturas e estresse hídrico os principais limitantes da fixação biológica de nitrogênio (HUNGRIA et al, 2001).…”

Section: Fatores Que Influenciam O Crescimento E Desenvolvimento Da Sojaunclassified

Estimativa de parâmetros genéticos para caracteres agronômicos e avaliação da qualidade fisiológica de sementes em duas populações F2 de soja

Bernardes¹

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BERNARDES, MURILO HENRIQUE DE DEUS. Estimation of genetic parameters for agronomic traits and evaluation of the physiological quality of seeds in two soybean populations. 2019. 43f. Dissertation (Masters in Agronomy-area of concentration in Phytotechnology)-Federal University of Uberlândia, Uberlândia 1. Obtaining more productive genotypes of soybean cultivation is one of the main objectives of breeding programs. There are few studies on the selection of agronomic traits associated with the quality and performance of soybean seeds. The objective of this work was to estimate genetic parameters of agronomic traits, seed quality and grain yield in soybean segregating populations, from parents with different seed quality history. The following cultivars were used to obtain segregant populations: NS 7200 RR, NS 7670 RR and UFUS 6901. The crossing block was installed in a greenhouse, with the following combinations: (1) UFUS 6901 x NS 7200 RR and (2) UFUS 6901 x NS 7670 RR. From the artificial hybridizations the F1 seeds were generated, which were harvested and seeded again to obtain the F2 seeds by means of their selffertilization. F2 seeds were sown in the field, by sowing in pits. For the combination 1, 66 seeds of cultivar UFUS 6901, 62 seeds of cultivar NS 7200 RR and 203 seeds of generation F2 were seeded. For the combination 2, were seeded 64 seeds of cultivar UFUS 6901, 64 seeds of cultivar NS 7670 RR and 230 seeds of generation F2. Agronomic traits were evaluated in all individuals: number of days for flowering (NDF) and maturity (NDM), plant height at flowering (PHF) and maturity (PHM), number of nodes at flowering (NNF) and maturity (NNM), height of first pod insertion (HPI), number of grains per pod (NGP), production of grains (PG) and weight of a thousand grains (WTG). Data were analyzed by means of analysis of generations and estimated the genetic parameters. For the three parental and both segregant populations, the physiological quality of the seed was evaluated by germination, germination and primary root length and fresh and dry matter of seedlings. The emergence and emergence speed index was also analyzed in a greenhouse under a sand bed. The physiological seed quality data were submitted to analysis of variance and, afterwards, submitted to the Tukey average test. Genetic-statistical analyzes were performed in the Genes Program (CRUZ, 2016). All the characters under study had medium to low heritability results, and the highest results were obtained for APF and WTG in the two combinations, being influenced by five and three genes, respectively. F2 populations have transgressive segregants for all the characters, except for NDM in combination 2. The combinations 1 and 2 allow the selection of superior individuals to be obtained in terms of precocity, height, number of nodes and productivity components, being promising genotypes in a soybean breeding program. The segregating populations did not present superior results in relation to the parents as to seed quality.

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Nitrogen Fixation with Soybean: The Perfect Symbiosis?

Hungría

Mendes

2015

Biological Nitrogen Fixation

132

165

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Symbiotic effectiveness of fast-growing rhizobial strains isolated from soybean nodules in Brazil

Cited by 36 publications

References 18 publications

Testing Whether Pre-Pod-Fill Symbiotic Nitrogen Fixation in Soybean Is Subject to Drift or Selection Over 100 Years of Soybean Breeding

Testing Whether Pre-Pod-Fill Symbiotic Nitrogen Fixation in Soybean Is Subject to Drift or Selection Over 100 Years of Soybean Breeding

Estimativa de parâmetros genéticos para caracteres agronômicos e avaliação da qualidade fisiológica de sementes em duas populações F2 de soja

Nitrogen Fixation with Soybean: The Perfect Symbiosis?

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