scholarly journals Geographical Distribution and Genetic Diversity of the Banana Fusarium Wilt Fungus in Laos and Vietnam

2022 ◽  
Vol 8 (1) ◽  
pp. 46
Author(s):  
Khonesavanh Chittarath ◽  
Chung Huy Nguyen ◽  
Wendy C. Bailey ◽  
Si-Jun Zheng ◽  
Diane Mostert ◽  
...  

Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. cubense (Foc), poses a major threat to global banana production. The tropical race 4 (TR4) variant of Foc is a highly virulent form with a large host range, and severely affects Cavendish bananas. Foc TR4 was recently observed within the Greater Mekong Subregion, after Chinese private companies expanded Cavendish production to the region. In this study, extensive surveys conducted across Laos and Vietnam show that Foc TR4 is still mainly constricted to the northern regions of these countries and is limited to Cavendish cultivation settings. In Laos, Foc TR4 is associated with large-scale Cavendish plantations owned by or involved with Chinese companies through which infected planting material could have been imported. In Vietnam, mostly small-holder Cavendish farmers and backyard gardens were affected by Foc TR4. In Vietnam, no direct link is found with Chinese growers, and it is expected the pathogen mainly spreads through local and regional movement of infected planting materials. Foc TR4 was not recorded on banana cultivars other than Cavendish. The extensively cultivated ‘Pisang Awak’ cultivar was solely infected by VCGs belonging to Foc race 1 and 2, with a high occurrence of VCG 0123 across Laos, and of VCG 0124/5 in Vietnam. Substantial diversity of Foc VCGs was recorded (VCGs 0123, 0124/5, 01218 and 01221) from northern to southern regions in both countries, suggesting that Fusarium wilt is well established in the region. Interviews with farmers indicated that the local knowledge of Fusarium wilt epidemiology and options for disease management was limited. Clear communication efforts on disease epidemiology and management with emphasis on biosecurity practices need to be improved in order to prevent further spread of Foc TR4 to mixed variety smallholder settings.

2015 ◽  
Vol 22 (4) ◽  
pp. 215-217
Author(s):  
M. Jayasree ◽  
V. Radhakrishnan ◽  
K. Mohanan

The influence of the status of planting materials such as mother rhizomes, primary fingers and secondary fingers on growth and yield of Kaempferia galanga L. was analyzed presently based on fifteen morphological characters. The study showed that there was not so much of influence for the status of the planting material on the growth and yield of Kaempferia galanga L. It further has shown that depending upon the availability, planting materials of different status can be used for propagation on a large scale without compromising on crop yield.


Author(s):  
Shaheena Parveen ◽  
Hidayatullah Mir ◽  
Tushar Ranjan ◽  
Awadhesh K. Pal ◽  
Manoj Kundu

The rate of pineapple propagation through conventional technique is quite low and time taken and that by seed is apparently hard to germinate. Non-availability of quality planting material is one of the major constraints for expansion of its cultivation area in Bihar. Keeping this in view an experiment was conducted for in vitro establishment for large scale disease free planting materials production. The most commonly encountered problem during in vitro pineapple germplasm establishment is the rate of contamination, which is very high in case of pineapple. Suckers of pineapple cultivar Kew were used as explants for the study. In this experiment the efficiency of three sterilizing agents (Clorox, HgCl2 and NaOCl) at different concentrations and duration was evaluated in terms of number of aseptic cultures. Results revealed that when no sterilant was used all the cultures were contaminated. The contamination of explants significantly decreased with increase in concentration of different sterilants and their time of exposure. The highest survival of explants (58.31±1.71%) were observed when explants were treated with Clorox 40% for 20 minutes which also resulted in 17.89±0.25% and 25.03±2.63%  mortality and per cent contamination respectively. As the duration of Clorox 40% was increased, percent contamination decreased but simultaneously increased the mortality rate at 25 mins of duration. The percent survival also increased when explants were treated with different concentrations of HgCl2 and NaOCl at different time durations. However, NaOCl treatments were less effective as compared to other two sterilants.


2020 ◽  
Vol 21 (4) ◽  
pp. 312-316
Author(s):  
Tingting Bai ◽  
Meng Qin ◽  
Xundong Li ◽  
Huacai Fan ◽  
Shengtao Xu ◽  
...  

Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) is one of the most destructive banana pathogens worldwide. Until now, it has been generally accepted that Foc TR4 mainly colonizes the roots, rhizomes, pseudostems, and leaves of banana plants and spreads among plantations with infected planting material, soil residues, and water. Because banana Fusarium wilt is a typical vascular bundle disease, the pathogen is accepted to possess the ability to enter the peduncle. However, no scientific proof has been presented. Recently, more and more signs of peduncle Foc TR4 in ‘Cavendish’ plants in different banana production provinces of China suggest that further investigations ought to be made regarding fungal colonization. We observed discoloration inside some peduncles from the Foc TR4-infected plants. The fungus isolated from these symptoms was identified using Foc TR4-specific PCR, sequencing, and a host inoculation assay. In a greenhouse bioassay, the Foc TR4 isolates from the peduncle showed the capacity for reinfecting Brazilian plants (Cavendish, AAA) up into the leaves. Collectively, we isolated the Foc TR4 from the peduncle and directly testified that this pathogen can invade the peduncle via xylem vascular bundle.


2020 ◽  
Vol 60 (1) ◽  
pp. 159-168
Author(s):  
V. V. Antonenko ◽  
A. V. Zubkov ◽  
S. N. Kruchina

Data were obtained on the basis of the results of research carried out on the territory of the educational and experimental farm of the Timiryazev State Agrarian University, in Moscow during 2018-2019. As a result of the surveys, the most dangerous diseases and pests of pome crops on the territory of this farm were established. The most resistant apple and pear varieties to major diseases have been identified. Peculiarities of development of alternariosis on pear are described, the harmfulness of the disease on pear and apple seedlings is noted. A possible role in the transfer of alternariosis infection from garden-protective plantations and weed vegetation to fruit trees was noted. A possible role has been established in the transport of septoriosis, powdery dew infection from dicotyledonous weeds plants. The peculiarities of the spread of infection under the influence of wind direction are noted. The results and peculiarities of the application of various methods of scaring birds in the orchard are presented. As a result of route surveys the most harmful weed plants have been identified. The possibility of using herbicides of different mechanism of action in fruit gardens for weed control has been studied. High efficiency and relative safety of application of herbicides of contact action in nursery fields, operational orchards and for control of piglets on fruit trees are shown. Recommendations are given for the use of soil and systemic herbicides of soil in seedlings beds, the first and second fields of the nursery, as well as in the process of production of large-scale planting material and operational orchards of fruit crops. The safety of the herbicides in question is established when used in accordance with the recommended methods of use.


Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 984-989 ◽  
Author(s):  
Sandra E. Branham ◽  
Amnon Levi ◽  
W. Patrick Wechter

Fusarium wilt race 1, caused by the soilborne fungus Fusarium oxysporum Schlechtend.: Fr. f. sp. niveum (E.F. Sm.) W.C. Snyder & H.N. Hans (Fon), is a major disease of watermelon (Citrullus lanatus) in the United States and throughout the world. Although Fusarium wilt race 1 resistance has been incorporated into several watermelon cultivars, identification of additional genetic sources of resistance is crucial if a durable and sustainable level of resistance is to be continued over the years. We conducted a genetic mapping study to identify quantitative trait loci (QTLs) associated with resistance to Fon race 1 in segregating populations (F2:3 and recombinant inbred lines) of Citrullus amarus (citron melon) derived from the Fon race 1 resistant and susceptible parents USVL246-FR2 and USVL114, respectively. A major QTL (qFon1-9) associated with resistance to Fon race 1 was identified on chromosome 9 of USVL246-FR2. This discovery provides a novel genetic source of resistance to Fusarium wilt race 1 in watermelon and, thus, an additional host-resistance option for watermelon breeders to further the effort to mitigate this serious phytopathogen.


2012 ◽  
Vol 10 (3) ◽  
pp. 258-260 ◽  
Author(s):  
Mohar Singh ◽  
Z. Khan ◽  
Krishna Kumar ◽  
M. Dutta ◽  
Anju Pathania ◽  
...  

Fusarium wilt caused by Fusarium oxysporum, Schlecht. emend. Snyd. & Hans. f. sp. ciceri is prevalent in most chickpea-growing countries and is a major devastating disease. Host plant resistance is the most practical method of disease management. Indigenous chickpea germplasm reveals a heterogeneous genetic make-up and the response of resistance to wilt is an unexplored potential source for disease resistance. There are 70 indigenous germplasm lines selected on the basis of their agronomic performance and diverse areas of collections in the country. Of these, four accessions had a highly resistant score of 1 and six had a score of 3 using a 1–9 rating scale, indicating their level of resistance to Fusarium wilt (race 4). Other germplasm accessions of chickpea were found to be moderately resistant to highly susceptible disease reaction. Likewise, the same set of germplasm was also screened for Meloidogyne incognita (race 1) using pot culture under controlled condition. Only one accession was found to be resistant to this pest. These resistant gene sources can be utilised effectively for race-specific chickpea wilt and root-knot resistance breeding programmes.


1995 ◽  
Vol 27 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Svante Hugosson ◽  
Sven-Arne Silfverdal ◽  
öjan Garpenholt ◽  
Elisabeth Esbjörner ◽  
Bo Lindquist ◽  
...  

Crop Science ◽  
2015 ◽  
Vol 55 (6) ◽  
pp. 2639-2646 ◽  
Author(s):  
Shalu Jain ◽  
Norman F. Weeden ◽  
Ajay Kumar ◽  
Kishore Chittem ◽  
Kevin McPhee

Plant Disease ◽  
2019 ◽  
Vol 103 (4) ◽  
pp. 721-728 ◽  
Author(s):  
T. V. Nguyen ◽  
L. T. T. Tran-Nguyen ◽  
C. L. Wright ◽  
P. Trevorrow ◽  
K. Grice

Panama disease caused by Fusarium oxysporum f. sp. cubense has devastated banana production worldwide. This work aimed to determine effective disinfectants against two races of F. oxysporum f. sp. cubense, race 1 and tropical race 4 (TR4), for implementation with on-farm biosecurity procedures against this disease following the outbreak of TR4 in North Queensland in 2015. A total of 32 commercial disinfectants were screened and their activity was assessed after ≤30 s, 5 min, 30 min, and 24 h of contact with an F. oxysporum f. sp. cubense suspension containing 105 chlamydospores/ml without and with soil added (0.05 g/ml). Of the disinfectants tested, the quaternary ammonium compounds containing ≥10% active ingredient were found to be the most effective against both F. oxysporum f. sp. cubense races. These products, when used at a 1:100 dilution, completely inhibited the survival of all F. oxysporum f. sp. cubense propagules across all the contact times regardless of the absence or presence of soil. The bioflavonoid product EvoTech 213 and bleach (10% sodium hypochlorite) used at a 1:10 dilution also eliminated all F. oxysporum f. sp. cubense propagules across all the contact times. None of the detergent-based or miscellaneous products tested were completely effective against both F. oxysporum f. sp. cubense races even used at a 1:10 dilution. Soil decreases the efficacy of disinfectants and therefore must be removed from contaminated items before treatments are applied.


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