Application to soil of disinfectants through irrigation reduces Verticillium dahliae in the soil and verticillium wilt of olive     

F. J. Gómez-Gálvez  V. Vega-Macías  J. C. Hidalgo-Moya  J. J. Hidalgo-Moya  D. Rodríguez-Jurado 《Plant pathology》2020,69(2):272-283

The application of disinfectants through drip irrigation could be a feasible practice against verticillium wilt (Verticillium dahliae) of olive. OX-VIRIN (activated peroxide) and OX-AGUA AL25 (quaternary ammonium compounds) are two disinfectants that have shown efficacy against V. dahliae in irrigation water and potential for reducing the disease in young olive plants. In this work, various post-planting application strategies incorporating OX-VIRIN (once a month, or twice a month on alternate or successive weeks) or OX-AGUA AL25 (once a month, or twice a month on alternate weeks) were assessed for their effect on V. dahliae in soil, disease in olive trees, and olive yield, in a 2-year pot-experiment under natural environmental conditions. The disinfectants were injected via metering pumps into a drip irrigation system that irrigated olive trees planted in V. dahliae-inoculated soil. All the application strategies significantly reduced the total inoculum density in soil compared to controls with no disinfectants and noninoculated soil. The microsclerotia density was also significantly reduced in disinfested soils by 73.6–86.8%, depending on the strategy. The symptoms and infection incidence were always lower in treatments subjected to disinfestation. The treatment with OX-AGUA AL25 applied twice a month on alternate weeks most reduced the symptoms (by 53.0%) and colonization index (by 70.8%) with respect to untreated water control. This soil disinfestation also significantly strengthened the symptom remission. Tree growth and production were negatively affected by soil inoculation (reduced by 45.6% and 88.7%, respectively), but not so by disinfectants, which even relieved the reduction in inoculated soils, especially when OX-AGUA AL25 was applied.  相似文献   

A new standard area diagram set for assessment of severity of soybean rust improves accuracy of estimates and optimizes resource use     

Vinicius T. Franceschi  Kaique S. Alves  Sergio M. Mazaro  Cláudia V. Godoy  Henrique S. S. Duarte  Emerson M. Del Ponte 《Plant pathology》2020,69(3):495-505

Soybean rust (SBR), caused by Phakopsora pachyrhizi, is the most important yield-damaging fungal disease of soybean due to severe reduction in healthy leaf area and acceleration of leaf fall. In experimental research, SBR severity is estimated visually aided/trained by a standard area diagram (SAD) developed and validated during the mid-2000s (Old SAD). In this study, we propose a new SAD set for SBR with six true-colour diagrams following linear increments (c. 15% increments) amended with four additional diagrams at low (<10%) severities, totalling 10 diagrams (0.2%, 1%, 3%, 5%, 10%, 25%, 40%, 55%, 70%, and 84%). For evaluation, 37 raters were split into two groups. Each assessed severity in a 50-image sample (0.25%–84%), first unaided and then using either the Old SAD or the New SAD. Accuracy, precision, and reliability of estimates improved significantly relative to unaided estimates only when aided by the New SAD (accuracy >0.95). Low precision (<0.78) and a trend of underestimation with an increase in severity were the main issues with the Old SAD, which did not differ from unaided estimates. Simulation to evaluate the impact of the errors by different methods on hypothesis tests, showed that the new SAD was more powerful for detecting the smallest difference in mean control (e.g., 70% vs. 65% disease reduction) than the Old SAD; the latter required a 2-fold increase in sample size to achieve the same power. There is a need to improve some SADs, taking advantage of new knowledge and technology to increase accuracy of the estimates, and to optimize both resource use efficiency and management decisions.  相似文献   

Retrospect on in vitro androgenesis of sorghum (Sorghum bicolor)     

Paul Chege  Csaba Lantos  János Pauk 《Plant Breeding》2020,139(6):1043-1051

Development of sorghum hybrids can immensely benefit from an enhanced anther culture protocol since the resultant doubled haploids would accelerate, as in other major cereal crops, the attainment of homozygosity and fixation of alleles. Production of the hybrids that have got high yielding, stress tolerance and other traits of industrial significance in a shorter time as compared to the current trend can hence be realized. This review presents the advances that have been made in the development of such a protocol, with closer attention to androgenic induction components of pre-treatment, culture media composition and conditions as well as ploidy determination and eventual chromosome doubling. From the findings of this review, it is clear that further work is desired to ensure a protocol, that to a large degree, breaks the genotype dependency trend that has been widely cited to impede the usability of the tested protocols.  相似文献   

Genome-wide in silico analysis of SOD genes in common bean (Phaseolus vulgaris L.)     

Silva  Silviany Angelica Fernandes  Silva  Fláive Loyze Baldassarini  Ribas  Alessandra Ferreira  de Souza  Silvia Graciele Hülse  dos Santos  Tiago Benedito 《Journal of Crop Science and Biotechnology》2020,23(3):241-251

Journal of Crop Science and Biotechnology - Superoxide dismutases (SODs) are a group of enzymes that play essential roles in catalyzing the dismutation of superoxide radicals to protect cells from...  相似文献   

Phytophthora oleae,a new root pathogen of wild olives     

M. González  A. Pérez-Sierra  M. E. Sánchez 《Plant pathology》2019,68(5):901-907

Wild olive (Olea europaea subsp. europaea var. sylvestris) is an important component of Mediterranean forests and a key genetic source for olive improvement programmes. Since 2009, a severe decline caused by Phytophthora cryptogea and P. megasperma has been detected in a protected wild olive forest of high ecological value (Dehesa de Abajo, Seville, Spain). In this natural forest, sampling of roots and soil was carried out on 25 wild olives with symptoms in 2014 and 2015. Apart from the already known P. cryptogea A1 and P. megasperma, a third Phytophthora species was consistently isolated from wild olive rootlets with symptoms. These isolates conformed morphologically with the newly described species P. oleae and were confirmed by analysis of their ITS regions and cox1 sequences. Temperature–growth relationships showed a maximum growth at 19.9 °C on carrot agar medium, making it the lowest temperature Phytophthora species infecting wild olive roots. Pathogenicity was confirmed on 1-year-old healthy wild olive seedlings and was similar to the previously known pathogenic phytophthoras. As temperature requirements are quite different, the three Phytophthora species may be active against wild olive roots in different seasons. However, the prevalence of P. oleae infecting wild olives in recent years could be due to its introduction as a new invasive pathogen. The probable invasive nature of P. oleae, together with increasing rain episodes concentrated in short periods frequent in southern Spain, would allow the outbreak of infections in wild olive forests, and also put cultivated olive orchards at risk.  相似文献   

The structural classification of field boundaries in Mediterranean arable cropping systems allows the prediction of weed abundances in the boundary and in the adjacent crop     

A Cirujeda  G Pardo  A I Marí  J Aibar  Y Pallavicini  J L Gonzlez‐Andújar  J Recasens  X O Sol‐Senan 《Weed Research》2019,59(4):300-311

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Distribution and diversity of leaf-cutting ants in Northeastern Argentina: species most associated with forest plantations     

Andrés F. Sánchez-Restrepo  Nadia L. Jiménez  Viviana A. Confalonieri  Luis A. Calcaterra 《国际虫害防治杂志》2019,65(3):244-257

Abstract

Leaf-cutting ants (LCA) are considered one of the main herbivores and one of the most destructive pest insects of the Neotropics. Northeastern Argentina harbors the greatest species richness of these ants and in turn comprises the highest surface with forest plantations. Our aim was to establish which species of leaf-cutting ants are most commonly associated with forest plantations by analyzing their geographic distribution using published and unpublished species occurrence data. Also, estimate their potential areas of distribution along a latitudinal gradient that entirely encompasses northeastern Argentina using Ecological Niche Modeling. Only seven of the 20 species recorded were strongly associated with productive systems along the gradient, but only 2–3 species in each region could be considered high-risk species for forest plantations. High-risk species composition shows a turnover between regions. Our models show the potential distribution areas where LCA could become more abundant and dominant, and possibly causing a detrimental effect on the forest plantations in the studied region. We find that ecological niche models are useful tools to assess the environmental suitability of important LCA.  相似文献   

Enhancement of gilthead seabream (Sparus aurata) larval growth by dietary vitamin E in relation to two different levels of essential fatty acids     

E. Atalah  C. M. Hernández‐Cruz  R. Ganga  E. Ganuza  T. Benítez‐Santana  J. Roo  H. Fernández‐Palacios  M. S. Izquierdo 《Aquaculture Research》2012,43(12):1816-1827

The objective of this study was to determine the effect of dietary vitamin E on gilthead seabream (Sparus aurata) growth and survival, at two different highly unsaturated fatty acids (HUFAs) levels. Eighteen days old gilthead seabream larvae were fed four formulated experimental diets combining two different dietary levels of HUFAs (M: medium 2.5 + 1.5, DHA + EPA, H: high 5 + 2.5 DHA + EPA g per 100 g) with two different levels of vitamin E (M: medium 540 mg kg^?1, H: high 2900 mg kg^?1): MM, MH, HM, HH (HUFA/vitamin E). After 2‐week feeding trial, the average survival rate was 52.6% and there were no significant differences found among treatments. Increase in vitamin E up to high level markedly improved larval growth, particularly when dietary HUFA levels were lower, suggesting a higher protection value when these fatty acids are more limiting. At medium dietary HUFA levels, increase in vitamin E from medium to high level enhanced larval growth performance in terms of total length. Moreover, increase in vit E enhanced HUFAs content in the larval polar lipids denoting the anti‐oxidative effect of vitamin E.  相似文献   

Genetic parameters for spawning and growth traits in the Pacific white shrimp (Penaeus (Litopenaeus) vannamei)          下载免费PDF全文

Alejandra Caballero‐Zamora  Eugenia Guadalupe Cienfuegos‐Rivas  Hugo H Montaldo  Gabriel Ricardo Campos‐Montes  Alfonso Martínez‐Ortega  Héctor Castillo‐Juárez 《Aquaculture Research》2015,46(4):833-839

The aim of this study was to estimate genetic parameters for spawning traits and growth traits in a breeding line of Pacific white shrimp, Penaeus (Litopenaeus) vannamei, selected for growth and survival. Traits studied were number of eggs (NE) and number of nauplii (NN) and female body weight at insemination (FWI) and body weight at 130 days of age (BW130). Genetic parameters were estimated using a multivariate animal model. Heritability for NE and NN were estimated as 0.13 ± 0.04 and 0.03 ± 0.04 respectively. The contribution to NN total variation due to ‘factors associated with male’ effect was estimated as 0.47 ± 0.07. In the cases of FWI and BW130, heritability was estimated as 0.44 ± 0.08 and 0.19 ± 0.03 respectively. Genetic correlation between FWI and NE was estimated as 0.49 ± 0.15, between FWI and NN as 0.54 ± 0.39 and between NE and NN as 0.27 ± 0.41, whereas the genetic correlations of FWI, NE and NN with BW130 were 0.30 ± 0.13, ?0.21 ± 0.19 and ?0.25 ± 0.38 respectively. Although it is important to perform more studies on this issue, our results found no evidence of a genetic antagonistic effect between female reproductive traits and body weight at harvesting (130 days of age) in P. vannamei.  相似文献   

Histological alterations in gills of shrimp Litopenaeus vannamei in low‐salinity waters under different stocking densities: Potential relationship with nitrogen compounds          下载免费PDF全文

Marcela G. Fregoso‐López  María S. Morales‐Covarrubias  Miguel A Franco‐Nava  Javier Ramírez‐Rochín  Juan F Fierro‐Sañudo  Jesús T Ponce‐Palafox  Federico Páez‐Osuna 《Aquaculture Research》2017,48(12):5854-5863

Two experimental modules with different stocking densities (M1 = 70 and M2 = 120 shrimp /m²) were examined weekly over a culture cycle in tanks with low‐salinity water (1.9 g/L) and zero water exchange. Results showed survival rates of 87.7 and 11.9% in M1 and M2, respectively. Water temperature, pH, dissolved oxygen, electrical conductivity and chlorophyll a were not significantly (p > .05) different between modules. In contrast, the concentrations of nitrogen compounds were significantly (p < .05) different between modules, except nitrite‐N (M2 were 2.31 ± 1.38 mg/L N‐TAN, 0.18 ± 0.49 mg/L N‐NO₂^? and 6.83 ± 6.52 mg/L N‐NO₃^?; in M1: 0.97 ± 0.73 mg/L N‐TAN, 0.05 ± 0.21 mg/L N‐NO₂^? and 0.63 ± 0.70 mg/L N‐NO₃^?). When waters of both modules reached higher levels of ammonia and nitrite, histological alterations were observed in gills. The histological alterations index (HAI) was higher in M2 (5‐112) than in M1 (2‐22).  相似文献