Riptortus.

Author(s):  
Un Taek Lim

Abstract R. pedestris causes up to 54% reduction in lipid content in soybean seed (Bae et al., 2014) and 8% seed sterility in soybean in Shizuoka Prefecture, Japan (Ikeda and Fukazawa, 1983). In another study, Kadosawa (1981) estimated 6.2% soybean damage in Northern Honshu and 26% in Shikoku, Japan. R. pedestris also transmits yeast-spot disease (Eremothecium coryli) in up to 81.6% of immature soybean seeds in Kyoto, Japan (Kimura et al., 2008). R. linearis damage on soyabean in India is reported to be 30-40% (Kashyap and Adlakha, 1971). R. linearis is estimated to cause (along with two other pod feeders) 19-39% pod and seed damage on soyabean in Indonesia (Supriyatin, 1992). In Nigeria, R. dentipes and Anoplocnemis curvipes cause 20-39% pod damage on Vigna unguiculata (Khaemba, 1984).

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 255
Author(s):  
Wenjing Li ◽  
Yu Gao ◽  
Yinglu Hu ◽  
Juhong Chen ◽  
Jinping Zhang ◽  
...  

The bean bug, Riptortus pedestris, is a major pest of soybeans. In order to assess the critical stages of soybean damage by R. pedestris, we tested the damage to soybeans at different growth stages (R2, R4, and R6) caused by five densities of R. pedestris (1, 2, 3, 4, and 5) through a field cage experiment. The results show that the R4 stage was the most sensitive stage in terms of suffering R. pedestris injury damage, followed by the R6 stage and then the R2 stage. The number of stay green leaves was 7.04 per plant, the abortive pod rate of the soybeans was 56.36%, and the abortive seed rate of the soybeans was 46.69%. The dry weight of the soybeans was 14.20 g at the R4 stage; these values of R4 were significantly higher than at the R2 and R6 stages. However, the dry weight of soybean seed was 4.27 g and the nutrient transfer rate was 27.01% in the R4 stage; these values were significantly lower than in the R2 and R6 stages. The number of stay green leaves, abortive pod rates, and abortive seed rates were all increased significantly with increasing pest density at each stage of soybean growth. However, the nutrient transfer rate was significantly decreased with the increase in the pest density. Soybean nutrition factors changed after they suffered R. pedestris injury; the lipid content of the soybean seed decreased and the lipid content of the soybean plant increased compared to controls, when tested with a density of five R. pedestris in the R4 stage. These results will be beneficial to the future management of R. pedestris in soybean fields.


2021 ◽  
Vol 43 ◽  
Author(s):  
Thiago Barbosa Batista ◽  
Samara Moreira Perissato ◽  
Carlos Henrique Queiroz Rego ◽  
Gustavo Roberto Fonseca de Oliveira ◽  
Fernando Augusto Henning ◽  
...  

Abstract: The analysis of longevity can support decisions about the length of seed lot storage until commercialization, since this characteristic implies the maintenance of viability over time. Seed longevity is analyzed by the p50 test, which expresses the time to lose 50% of the initial viability. Seeds with high vigor and germination have greater physiological potential and, thus, a greater capacity to maintain quality throughout the storage period. However, there has been little research on the correlations between the analysis of p50 (longevity) and the tests used to measure physiological potential (germination and vigor) of lots, which can be used as a tool to make inferences about longevity using the most traditional tests. Thus, the objective of this study was to investigate which tests used to measure the potential of lots can estimate p50. To this end, germination and vigor were evaluated using traditional tests while longevity was assessed in eight soybean seed lots. Correlations and linear regression were tested for the traditional variables versus p50. It was found that the use of accelerated aging, electrical conductivity, and time to 50% radicle protrusion has high potential to estimate longevity as measured by p50.


2002 ◽  
Vol 65 (12) ◽  
pp. 1984-1987 ◽  
Author(s):  
J. E. MELLON ◽  
P. J. COTTY

Soybean lines lacking lipoxygenase (LOX) activity were compared with soybean lines having LOX activity for the ability to support growth and aflatoxin B1 production by the fungal seed pathogen Aspergillus flavus. Whole seeds, broken seeds, and heat-treated (autoclaved) whole seeds were compared. Broken seeds, irrespective of LOX presence, supported excellent fungal growth and the highest aflatoxin levels. Autoclaved whole seeds, with or without LOX, produced good fungal growth and aflatoxin levels approaching those of broken seeds. Whole soybean seeds supported sparse fungal growth and relatively low aflatoxin levels. There was no significant difference in aflatoxin production between whole soybean seeds either with or without LOX, although there did seem to be differences among the cultivars tested. The heat treatment eliminated LOX activity (in LOX+ lines), yet aflatoxin levels did not change substantially from the broken seed treatment. Broken soybean seeds possessed LOX activity (in LOX+ lines) and yet yielded the highest aflatoxin levels. The presence of active LOX did not seem to play the determinant role in the susceptibility of soybean seeds to fungal pathogens. Seed coat integrity and seed viability seem to be more important characteristics in soybean seed resistance to aflatoxin contamination. Soybean seeds lacking LOX seem safe from the threat of increased seed pathogen susceptibility.


2012 ◽  
Vol 34 (2) ◽  
pp. 225-230
Author(s):  
Elisandra Batista Zambenedetti Magnani ◽  
Elisabeth Aparecida Furtado de Mendonça ◽  
Maria Cristina de Figueiredo e Albuquerque

To study adhesion and viability of uredospores of the fungus Phakopsora pachyrhizi on soybean seeds during storage, suspension tests of those uredospores were carried out by washing seeds at each 30 days interval. Furthermore, germination and inoculation tests of uredospores on soybean plants were performed with uredospores collected from seeds of two soybean production areas, located in the municipalities "Chapada dos Guimarães" and "Tangará da Serra", State of Mato Grosso, Brazil. High levels of uredospores infestation were detected before storage [249.31 and 85.18 uredospores/100 seeds (U/100)] on seeds collected in both localities, respectively. After 30 days storage, these figures were 46.12 and 122.5 U/100; at 60 days were 14.62 and 26.62 U/100; and at 90 days were only 2.87 and 3,68 U/100, respectively; dropping to zero after 120 days storage. The percentage of germinated uredospores decreased with increasing storage periods and at 120 days germination percentage was nil. When uredospores were inoculated on soybean plants, rust symptoms were only observed for uredospores collected from freshly harvested seeds. Uredospores associated to soybean seed germinate until 90 days after storage, but are not viable after this time span. Infection of plants only occurs with inoculation of uredospores obtained from freshly harvested seeds.


2018 ◽  
Vol 40 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Danielle Helena Müller ◽  
Elisangela Clarete Camili ◽  
Walcylene Lacerda Matos Pereira Scaramuzza ◽  
Maria Cristina de Figueiredo e Albuquerque

Abstract: The objective of this study was to evaluate the spatial variability in soybean seeds quality and in soil chemical attributes of a production field. Data were collected at 138 georeferenced points of a soybean production property located in Santo Antônio de Leverger - MT. Soil related variables, such as phosphorus, potassium, calcium, magnesium, and organic matter (OM) contents, pH, cation exchange capacity (CEC) and base saturation (V%) were evaluated. On the other hand, yield, one thousand seed mass, size, germination, emergence in seedbed, electrical conductivity, accelerated aging and tetrazolium reaction were evaluated as seed variables. The data were submitted to descriptive and geostatistical analysis, and the fit semivariogram parameters were used to elaborate spatial distribution maps of the analyzed variables. After the analysis, it was possible to conclude that there was spatial variability in the evaluated attributes for both seeds and soil related variables, indicating that the soybean seed production area can be divided into management zones, which allows the definition of areas to be harvested or discarded within a field of seed production.


2019 ◽  
Vol 20 (9) ◽  
pp. 2202 ◽  
Author(s):  
Songnan Yang ◽  
Long Miao ◽  
Jianbo He ◽  
Kai Zhang ◽  
Yan Li ◽  
...  

Soybean is one of the most important oil crops in the world. Revealing the molecular basis and exploring key candidate genes for seed oil synthesis has great significance for soybean improvement. In this study, we found that oil accumulation rates and gene expression levels changed dynamically during soybean seed development. The expression levels of genes in metabolic pathways such as carbon fixation, photosynthesis, glycolysis, and fatty acid biosynthesis were significantly up-regulated during the rapid accumulation of oil in developing soybean seeds. Through weighted correlation network analysis, we identified six co-expression modules associated with soybean seed oil content and the pink module was the most positively correlated (r = 0.83, p = 7 × 10−4) network. Through the integration of differential expression and co-expression analysis, we predicted 124 candidate genes potentially affecting soybean seed oil content, including seven genes in lipid metabolism pathway, two genes involved in glycolysis, one gene in sucrose metabolism, and 12 genes belonged to transcription factors as well as other categories. Among these, three genes (GmABI3b, GmNFYA and GmFAD2-1B) have been shown to control oil and fatty acid content in soybean seeds, and other newly identified candidate genes would broaden our knowledge to understand the molecular basis for oil accumulation in soybean seeds.


Author(s):  
Yelandur Somaraju Deepika ◽  
Shivannegowda Mahadevakumar ◽  
Kestur Nagaraj Amruthesh ◽  
Nanjaiah Lakshmidevi

2001 ◽  
Vol 1 (1) ◽  
pp. 38-44 ◽  
Author(s):  
K. Meksem ◽  
V. N. Njiti ◽  
W. J. Banz ◽  
M. J. Iqbal ◽  
My. M. Kassem ◽  
...  

Soy products contain isoflavones (genistein, daidzein, and glycitein) that display biological effects when ingested by humans and animals, these effects are species, dose and age dependent. Therefore, the content and quality of isoflavones in soybeans is a key to their biological effect. Our objective was to identify loci that underlie isoflavone content in soybean seeds. The study involved 100 recombinant inbred lines (RIL) from the cross of ‘Essex’ by ‘Forrest,’ two cultivars that contrast for isoflavone content. Isoflavone content of seeds from each RIL was determined by high performance liquid chromatography (HPLC). The distribution of isoflavone content was continuous and unimodal. The heritability estimates on a line mean basis were 79% for daidzein, 22% for genistein, and 88% for glycitein. Isoflavone content of soybean seeds was compared against 150 polymorphic DNA markers in a one-way analysis of variance. Four genomic regions were found to be significantly associated with the isoflavone content of soybean seeds across both locations and years. Molecular linkage group B1 contained a major QTL underlying glycitein content (P=0.0001,R 2=50.2%), linkage groupNcontained a QTL for glycitein (P=0.0033,R 2=11.1%) and a QTL for daidzein (P=0.0023,R 2=10.3%) and linkage groupA1contained a QTL for daidzein (P=0.0081,R 2=9.6%). Selection for these chromosomal regions in a marker assisted selection program will allow for the manipulation of amounts and profiles of isoflavones (genistein, daidzein, and glycitein) content of soybean seeds. In addition, tightly linked markers can be used in map based cloning of genes associated with isoflavone content.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Defang Zeng ◽  
Xinrong Luo ◽  
Renjie Tu

Soybean seeds suffer attacks of various pests that result in a decreased yield in northeastern China. Until recently, people use pesticides such as insecticides to achieve the goal of controlling pests. Chitosan extracted from deacetylation of chitin is promising candidates as a seed-coating agent to control agrotis ypsilon, soybean pod borer, and soybean aphid effectively. An experimental study on influences of chitosan with different concentrations on pest controlling and soybean growth was made in the paper. Coating based on chitosan was used as a feeding deterrent and for enhancing the germination and quality of soybean seeds. Results indicated that all chitosan coating had a significant effect on antifeeding against pests; with the increasing concentration, antifeedant rate (AR) were increased obviously, especially when in the concentration of 5%, santifeedant rate of agrotis ypsilon, soybean pod borer, and soybean aphid reached 82.89%, 87.24%, and 80.21%, respectively. Also chitosan coating increased seed germination, plant growth, and soybean yield efficiently, especially when, in the concentration of 5%, the yield was increased by about 20% compared with CK. The application of chitosan in soybean seed coated is an appropriate option to control pests replacing high-toxicity pesticides and enhance soybean yield.


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