scholarly journals Effect of plant growth-promoting rhizobacteria and gibberellic acid on salt stress tolerance in tomato genotypes.

1970 ◽  
Vol 28 (3) ◽  
pp. 341-362
Author(s):  
A.M. Esan ◽  
C.O. Olaiya ◽  
L.O. Anifowose ◽  
I.O. Lana ◽  
B.V. Ailenokhuoria ◽  
...  

Salinity stress is a limiting factor that affects attainment of optimal yield of many vegetable crops at various growth stages in many arid and semi-arid parts of sub-Saharan Africa. The objective of this study was to explore salt tolerance of tomato (Solanum lycopersicum L.) genotypes under the influence of gibberellic acid (GA3) and Bacillus subtilis under screen house conditions. Tomato seeds were pre-soaked with 0, 0.4, 0.5 or 0.6 mM concentrations of GA3 and control in distilled water, respectively; for 12 hr at room temperature. The seeds were germinated in a screen house in 10 kg of soil contained 0, 100, or 200 mM NaCl treatment in polyethene bags. After two weeks of seed germination, the seedlings were inoculated with B. subtilis with the exception of controls. Results revealed that the single or combined treatments of GA3 (at different concentrations) and Bacillus subtilis significantly (P<0.05) increased photosynthetic pigments, and enhanced the concentrations of potassium, calcium, magnesium and phosphorus ions in the salt-stressed tomato. Both tomato genotypes showed low concentrations of sodium ions at all levels of gibberellic acid with Bacillus subtilis. Also, there were significant (P < 0.05) increases in the compatible solutes, antioxidant enzymes activity and antioxidant potential of salt-stressed tomato genotypes, in the combined treatments of GA3 and Bacillus subtilis. Tomato genotypes treated with GA3 and Bacillus subtilis, showed greater salt-tolerance even at high levels of salinity, than single treatment of either GA3 or Bacillus subtilis. Based on these findings, the genotypes are suitable for future breeding programmes to achieve optimal crop yield in saline conditions.

Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 93
Author(s):  
Alessandro Miceli ◽  
Filippo Vetrano ◽  
Alessandra Moncada

Seed germination and early seedling growth are the plant growth stages most sensitive to salt stress. Thus, the availability of poor-quality brackish water can be a big limiting factor for the nursery vegetable industry. The exogenous supplementation of gibberellic acid (GA3) may promote growth and vigor and counterbalance salt stress in mature plants. This study aimed to test exogenous supplementation through foliar spray of 10−5 M GA3 for increasing salt tolerance of tomato and sweet pepper seedlings irrigated with increasing salinity (0, 25, and 50 mM NaCl during nursery growth. Tomato and sweet pepper seedlings suffered negative effects of salinity on plant height, biomass, shoot/root ratio, leaf number, leaf area, relative water content, and stomatal conductance. The foliar application of GA3 had a growth-promoting effect on the unstressed tomato and pepper seedlings and was successful in increasing salinity tolerance of tomato seedlings up to 25 mM NaCl and up to 50 mM NaCl in sweet pepper seedlings. This treatment could represent a sustainable strategy to use saline water in vegetable nurseries limiting its negative effect on seedling quality and production time.


2013 ◽  
Vol 2013 ◽  
pp. 1-10
Author(s):  
Mokhtar M. Abdel-Kader ◽  
Nehal S. El-Mougy

Integrated commercial blue-green algae extracts and bioagents treatments against vegetables root rot incidence when used as soil drench under greenhouse and plastic house conditions were evaluated. All applied treatments reduced significantly root rot incidence at both pre- and postemergence growth stages of cucumber, cantaloupe, tomato, and pepper plants compared with untreated check control. In pot experiment, the obtained results showed that treatments ofTrichoderma harzianumorBacillus subtiliseither alone or combined with commercial algae extracts were significantly superior for reducing root rot disease for two tested vegetable plants compared with the other tested treatments as well as control. It is also observed that rising concentrations of either algae products, Oligo-X or Weed-Max, were reflected in more disease reduction. Promising treatments for controlling root rot disease incidence were applied under plastic houses conditions. As for field trails carried out under plastic houses conditions at different locations, the obtained results revealed that the applied combined treatments significantly reduced root rot incidence compared with fungicide and check control treatments. At all locations it was observed that Weed-Max (2 g/L) +Bacillus subtilissignificantly reduced disease incidence of grown vegetables compared with Oligo-X (2 mL/L) +Trichoderma harzianumtreatments. An obvious yield increase in all treatments was significantly higher than in the control. Also, the harvested yield in applied combined treatments at all locations was significantly higher than that in the fungicide and control treatments.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 712
Author(s):  
Md Sarowar Alam ◽  
Mark Tester ◽  
Gabriele Fiene ◽  
Magdi Ali Ahmed Mousa

Salinity is one of the most significant environmental stresses for sustainable crop production in major arable lands of the globe. Thus, we conducted experiments with 27 tomato genotypes to screen for salinity tolerance at seedling stage, which were treated with non-salinized (S1) control (18.2 mM NaCl) and salinized (S2) (200 mM NaCl) irrigation water. In all genotypes, the elevated salinity treatment contributed to a major depression in morphological and physiological characteristics; however, a smaller decrease was found in certain tolerant genotypes. Principal component analyses (PCA) and clustering with percentage reduction in growth parameters and different salt tolerance indices classified the tomato accessions into five key clusters. In particular, the tolerant genotypes were assembled into one cluster. The growth and tolerance indices PCA also showed the order of salt-tolerance of the studied genotypes, where Saniora was the most tolerant genotype and P.Guyu was the most susceptible genotype. To investigate the possible biochemical basis for salt stress tolerance, we further characterized six tomato genotypes with varying levels of salinity tolerance. A higher increase in proline content, and antioxidants activities were observed for the salt-tolerant genotypes in comparison to the susceptible genotypes. Salt-tolerant genotypes identified in this work herald a promising source in the tomato improvement program or for grafting as scions with improved salinity tolerance in tomato.


Author(s):  
Rhoda Leask ◽  
Kenneth P. Pettey ◽  
Gareth F. Bath

Heartwater is a serious limiting factor for sheep and goat production in the major endemic area of sub-Saharan Africa and therefore most knowledge, research and control methods originate from this region. Whilst the usual or common clinical presentations can be used to make a presumptive diagnosis of heartwater with a good measure of confidence, this is not always the case, and animals suffering from heartwater may be misdiagnosed because their cases do not conform to the expected syndrome, signs and lesions. One aberrant form found occasionally in the Channel Island breeds of cattle and some goats is an afebrile heartwaterlike syndrome. The most constant and characteristic features of this heartwater-like syndrome comprise normal temperature, clinical signs associated with generalised oedema, and nervous signs, especially hypersensitivity. The presumption that the disease under investigation is the afebrile heartwater-like syndrome entails a tentative diagnosis based on history and clinical signs and the response to presumed appropriate treatment (metadiagnosis). The afebrile heartwater-like syndrome presents similarly to peracute heartwater but without the febrile reaction. Peracute cases of heartwater have a high mortality rate, enabling confirmation of the disease on post-mortem examination. Recognition of the afebrile heartwater-like syndrome is important to prevent deaths and identify the need for appropriate control measures.


2007 ◽  
Vol 59 (3) ◽  
pp. 227-231 ◽  
Author(s):  
S. Zivkovic ◽  
M. Devic ◽  
B. Filipovic ◽  
Z. Giba ◽  
D. Grubisic

The influence of high NaCl concentrations on seed germination in both light and darkness was examined in the species Centaurium pulchellum, C. erythraea, C. littorale, C. spicatum, and C. tenuiflorum. Salt tolerance was found to depend on the life history of the seeds. To be specific, seeds of all five species failed to complete germination when exposed to continuous white light if kept all the time in the presence of 100-200 mM and greater NaCl concentrations. However, when after two weeks NaCl was rinsed from the seeds and the seeds were left in distilled water under white light for an additional two weeks, all species completed germination to a certain extent. The percent of germination not only depended on NaCl concentration in the prior medium, but was also species specific. Thus, seeds of C. pulchellum, C. erythraea, and C. littorale completed germination well almost irrespective of the salt concentration previously experienced. On the other hand, seeds of C. tenuiflorum completed germination poorly if NaCl concentrations in the prior media were greater than 200 mM. When seeds after washing were transferred to darkness for an additional 14 days, they failed to complete germination if previously imbibed on media containing NaCl concentrations greater than 400 mM. However, the seeds of all species, even if previously imbibed at 800 mM NaCl, could be induced to complete germination in darkness by 1 mM gibberellic acid. .


Author(s):  
Beza Shewangizaw Woldearegay ◽  
Anteneh Argaw ◽  
Tesfaye Feyisa ◽  
Birhan Abdulkadir ◽  
Endalkachew Wold-Meskel

In sub-Saharan Africa, multiple plant nutrients deficiency besides nitrogen (N) and phosphorus (P) is a major growth-limiting factor for crop production. As a result, some soils become non-responsive for Rhizobium inoculation besides P application. Based on the soil test result, the soil of Experimental sites had low organic matter (OM), nitrogen (N), phosphorus (P), sulphur (S) and zinc (Zn)[xy1]. Hence, an experiment was carried out on-farm at Gondar Zuria woreda in Tsion and Denzaz Kebeles to evaluate the effect of Rhizobium inoculation, S and Zn application on yield, nodulation, N and P uptake of chickpea. The experiment included twelve treatments developed via factorial combination of two level of inoculation (Rhizobium inoculated, un-inoculated), three level of S (0, 15, 30 kg Sulphur ha-1) and two levels of Zn (0, 1.5 kg Zinc ha-1). The treatment was laid out in randomized complete block design with three replications. Results showed that the highest mean nodule number (15.3) and nodule volume (1.3 ml plant-1) over locations were obtained with Rhizobium inoculation integrated with 15 kg S and 1.5 kg Zn ha-1 which resulted in 37.8% and 116.7% increment over the control check, respectively. It was also observed that combined application of Rhizobium and 30 kg S ha-1 caused the highest (6.7) mean nodulation rating and seed yield (1775.5 kg ha-1) over locations which resulted in 86.1% and 28 % increase over the control check, respectively. Moreover, this treatment improved P use efficiency of chickpea. On the bases of observed result, it can be concluded that the response of chickpea to Rhizobium and P application can be improved by S application and Rhizobium inoculation with application of 30 kg S ha-1 with recommended rate of P and starter N is recommended for chickpea production at the experimental locations in Gonder Zuria Woreda.


Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2068-2073
Author(s):  
Christabell Nachilima ◽  
Godfree Chigeza ◽  
Mwila Chibanda ◽  
Hapson Mushoriwa ◽  
Brian D. Diers ◽  
...  

Soybean production has expanded worldwide including countries in sub-Saharan Africa. Several national and international agencies and research groups have partnered to improve overall performance of soybean breeding stocks and have introduced new germplasm from Brazil and the United States with the goal of developing new high-yielding cultivars. Part of this effort has been to test improved soybean lines/cultivars accumulated from private and public sources in multilocational trials in sub-Saharan Africa. These trials are known as the Pan-African Soybean Variety Trials, and the entries come from both private and public breeding programs. The objective of this research was to evaluate entries in the trials that include commercial cultivars or advanced experimental lines for the incidence and severity of foliar diseases. All trials were planted in December 2018 with six located in Zambia and one in Malawi. Plants were evaluated during the reproductive growth stages using a visual pretransformed severity rating scale. Foliar disease ratings were recorded for three bacterial diseases, six fungal diseases, one oomycete, and viruses. The overall occurrence of most of the diseases was high except for soybean rust and target spot, which were only found at two and one location, respectively. However, disease severity was generally low, although there were differences in disease severity ratings among the entries at some of the locations for brown spot, downy mildew, frogeye leaf spot, red leaf blotch, and soybean rust.


2012 ◽  
Vol 260-261 ◽  
pp. 1017-1021
Author(s):  
Xin Ying Wang ◽  
Yong Tao Liu ◽  
Min Hui ◽  
Ji Fei Xu

Escherichia coli and Bacillus subtilis as objects of the study, ultrasonic fragmentation acted on the bacterial cells in different growth stages, results showed that, it’s similar to the crushing effect of ultrasound on E. coli and B. subtilis cells of different growth stages, the highest crushing rate in the logarithmic phase, reached to 95.8% and 94.3% respectively, the crushing rate of adjustment phase is lowest, maintained at around 60%, the crushing rate stability cell was centered, which can be achieved 90%. The structure of the bacterial cell wall didn’t the main factor to decide the ultrasonic fragmentation effect, but different growth periods of bacterial cells did the determinant.


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