scholarly journals Plant parasitic nematodes occurrence and genetic diversity of banana cultivars grown in Tanzania

Plant Omics ◽  
2020 ◽  
pp. 21-29
Author(s):  
Doreen M. Mgonja ◽  
Gladness E. Temu ◽  
Sylvester L. Lyantagaye ◽  
Abdalah Makaranga ◽  
Joseph C. Ndunguru ◽  
...  

The genetic diversity of bananas (Musa spp.), one of the most economically important crops in Tanzania, is underestimated with scarce reports available. In addition, cultivation of banana is severely constrained by plant parasitic nematodes (PPN). We assessed genetic diversity and population structure of 159 banana varieties from four agro-ecological zones (Northern, Southern highlands, Lake and Zanzibar islands) of Tanzania using 20 SSR markers analysed with UPGMA method. We also, assessed the PPN occurrence through isolation and counting of PPN from each banana genotype where leaf samples were collected. SSR primer pairs were polymorphic; and generated 63 distinct reproducible bands. The polymorphic information content values of each SSR marker ranged from 0.50 to 0.75 indicating high level of genetic diversity among banana varieties. The 159 banana varieties were grouped into two clusters: A and B, based on UPGMA cluster and population structure analysis. A total of 128 independent and 31 overlapping genotypes were identified. Higher kinship among genotypes was observed in cluster A compared with cluster B. Some of the clusters in A and B genotypes showed high genetic distance. The most prevalent and abundant nematode species was Pratylenchus goodeyi with a mean count of 63%, followed by Radopholus similis (31%) and P. coffeae (6%). The results from this study provides a foundation for understanding genetic variability of bananas existing in Tanzania and PPN occurrence that will be valuable information for breeding disease and pest-resistant bananas with high yield traits.

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Manosh Kumar Biswas ◽  
Mita Bagchi ◽  
Ujjal Kumar Nath ◽  
Dhiman Biswas ◽  
Sathishkumar Natarajan ◽  
...  

Abstract Lily belongs to family liliaceae, which mainly propagates vegetatively. Therefore, sufficient number of polymorphic, informative, and functional molecular markers are essential for studying a wide range of genetic parameters in Lilium species. We attempted to develop, characterize and design SSR (simple sequence repeat) markers using online genetic resources for analyzing genetic diversity and population structure of Lilium species. We found di-nucleotide repeat motif were more frequent (4684) within 0.14 gb (giga bases) transcriptome than other repeats, of which was two times higher than tetra-repeat motifs. Frequency of di-(AG/CT), tri-(AGG/CTT), tetra-(AAAT), penta-(AGAGG), and hexa-(AGAGGG) repeats was 34.9%, 7.0%, 0.4%, 0.3%, and 0.2%, respectively. A total of 3607 non-redundant SSR primer pairs was designed based on the sequences of CDS, 5′-UTR and 3′-UTR region covering 34%, 14%, 23%, respectively. Among them, a sub set of primers (245 SSR) was validated using polymerase chain reaction (PCR) amplification, of which 167 primers gave expected PCR amplicon and 101 primers showed polymorphism. Each locus contained 2 to 12 alleles on average 0.82 PIC (polymorphic information content) value. A total of 87 lily accessions was subjected to genetic diversity analysis using polymorphic SSRs and found to separate into seven groups with 0.73 to 0.79 heterozygosity. Our data on large scale SSR based genetic diversity and population structure analysis may help to accelerate the breeding programs of lily through utilizing different genomes, understanding genetics and characterizing germplasm with efficient manner.


2016 ◽  
Vol 10 (1) ◽  
pp. 10-14
Author(s):  
Arvind K. Keshari ◽  
Ranjana Gupta

During a survey for plant parasitic nematodes affecting various vegetable crops grown in three hilly districts surrounding Kathmandu Valley, Nepal, five species of order Tylenchidae are reported for the first time from Nepal.The nematode species are Hoplolaimus indicus, Tylenchorhynchus mashhoodi, Helicotylenchus incisus, Microposthonia paraxestis and Hemicriconemoides cocophilus.All the species are illustrated with line diagrams and described with their morphometric data along with localities and host plants.International Journal of Life Sciences 10 (1) : 2016; 10-16


Plant Disease ◽  
2015 ◽  
Vol 99 (7) ◽  
pp. 982-993 ◽  
Author(s):  
Yongsan Zeng ◽  
Weimin Ye ◽  
James Kerns ◽  
Lane Tredway ◽  
Samuel Martin ◽  
...  

The near-full-length 18S ribosomal DNA (rDNA) gene and internal transcribed spacer 1 region were amplified and sequenced from 52 nematode populations belonging to 28 representative species in 13 families recovered from turfgrasses in North Carolina (38 populations) and South Carolina (14 populations). This study also included 13 nematode populations from eight other plant hosts from North Carolina for comparison. Nematodes were molecularly characterized and the phylogenetic relationships were explored based on 18S rDNA sequences. Phylogenetic analysis using Bayesian inference was performed using five groups of the plant-parasitic nematode populations Tylenchids, Criconematids, Longidorids, Xiphinematids, and Trichodorids. The 65 nematode populations were clustered correspondingly within appropriate positions of 13 families, including Belonolaimidae, Caloosiidae, Criconematidae, Dolichodoridae, Hemicycliophoridae, Hoplolaimidae, Heteroderidae, Longidoridae, Meloidogynidae, Paratylenchidae, Pratylenchidae, Telotylenchidae, and Trichodoridae. This study confirms previous morphological-based identification of the plant-parasitic nematode species found in turfgrasses and provides a framework for future studies of plant-parasitic nematodes associated with turfgrasses based upon DNA sequences and phylogenetic relationships.


Plant Disease ◽  
2006 ◽  
Vol 90 (4) ◽  
pp. 471-475 ◽  
Author(s):  
Enrique E. Pérez ◽  
Edwin E. Lewis

A 2-year experiment was conducted to test suppression of plant-parasitic nematodes on English boxwood using entomopathogenic nematodes and 3.5% thyme oil formulated as Promax. Treatments were Steinernema riobrave formulated as BioVector and S. feltiae formulated as Nemasys, both applied at a rate of 2.5 billion infective juveniles/ha, thyme oil at rate of 9.3 liters/ha, and nontreated control. In the 2001 season, treatment with S. feltiae reduced (P ≤ 0.05) the population growth of Tylenchorhynchus sp. 7 days after treatment and Hoplolaimus sp. 30 and 60 days after treatment. Treatment with S. riobrave reduced (P ≤ 0.05) the population growth of all plant-parasitic nematode species at all sampling dates, with the exception of Mesocriconema sp. 30 days after treatment and Tylenchorhynchus sp. and Rotylenchus buxophilus 60 days after treatment. Treatment with thyme oil reduced (P ≤ 0.05) the population growth of all plant-parasitic nematode genera at all sampling dates except Tylenchorhynchus sp. and R. buxophilus 60 days after treatment. In the 2002 season, treatment with S. feltiae had no effect on nematode population growth. Treatment with S. riobrave reduced (P ≤ 0.05) the population growth of R. buxophilus 7 days after treatment, and all plant-parasitic nematodes 30 and 60 days after treatment except Hoplolaimus sp. 30 days after treatment and Mesocriconema sp. 60 days after treatment. Treatment with thyme oil reduced (P ≤ 0.05) the population growth at all sampling dates of plant-parasitic nematodes except Mesocriconema sp. 60 days after treatment.


HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 264D-264
Author(s):  
John R. Clark ◽  
Robert Robbins

Two replicated blueberry plantings, one containing one highbush, (Vaccinium corymbosum) two southern highbush and two rabbiteye (V.ashei) cultivars, and another containing one highbush and three rabbiteye cultivars were sampled in October, 1991 and plant parasitic nematodes extracted and counted. Additionally, 15 commercial rabbiteye plantings were sampled. Standard and southern highbush samples had total plant parasitic nematode levels of 228-451 nematodes/250 ml soil compared to 4-14 nematodes/250 ml soil for rabbiteye. No difference in nematode population was found among the standard highbush ('Bluecrop') and southern highbush ('Cooper', 'Gulfcoast') cultivars. Xiphinema americanum was the most common nematode species found, along with very small populations of Paratrichodorus minor. All commercial plantings had lower nematode levels in samples from the blueberry plants as compared to those from the sod middles between the rows. Nematode levels from commercial plantings ranged from 1477/250ml soil from blueberry plants and 11-1546/250 ml soil from the sod middles. Species found at high levels in the sod samples were usually distinctly different from those found associated with the blueberry plants.


2021 ◽  
Author(s):  
Radwa G. Mostafa ◽  
Aida M. El-Zawahry ◽  
Ashraf E. M. Khalil ◽  
Ameer E. Elfarash ◽  
Ali D. A. Allam

Abstract Background Plant-parasitic nematodes are extremely dangerous pests in a variety of economically important crops. The purpose of this study was a survey of all nematode species existing in banana from three sites in Assiut Governorate, Egypt and to characterize the most common species by morphological, morphometric and molecular techniques (PCR with species-specific primers). Then, study of resistance or sensitivity of some banana cultivars to root-knot nematodes.Methods and Results Four nematodes, Meloidogyne, Rotylenchulus reniformis, Helicotylenchus and Pratylenchus were isolated and identified from soil and root samples collected from banana plants. Most frequently occurring of plant parasitic nematode species in banana was Meloidogyne. Former research found differences in species and in resistance to root-knot nematodes among the examined plant cultivars. Identification of Root-knot nematodes by Characterize of morphometric, molecularly, morphological isolate of Meloidogyne related to banana plants. The results revealed that the identified nematode species, Meloidogyne javanica, is the most common plant-parasitic nematodes in all locations. Data on the susceptibility of the tested banana cultivars to M. javanica revealed that Grand Naine was highly susceptible (HS) however, Magraby was susceptible (S) but Williams and Hindi cultivars were moderately resistant (MR).Conclusions we concluded that a survey revealed the significant prevalence of Meloidogyne javanica, the most important nematodes on banana in Assiut. The morphometric, morphological, and molecular identification were harmonic with one another. In addition to the host response of certain banana cultivars, to M. javanica that resistance is of significance and can be helpful to incorporate through planning control measures for root- knot nematodes.


Koedoe ◽  
1992 ◽  
Vol 35 (1) ◽  
Author(s):  
Esther Van den Berg

Two new O^nia Southern, 1914 species are described and figured from Giant's Castle Nature Reserve, Kamberg Nature Reserve and the Royal Natal National Park. O^ma naomiae spec. nov. females are characterised by having 10 to 12 longitudinal rows of scales on 63 to 69 retrorse body annuli; scales haphazardly arranged on first nine to 10 annuli; scales mostly with two projections, becoming longer toward tail end; all scales with minute protuberances on outer edges; lip region with one annulus with a greater diameter than first body annulus. Juveniles with 14 to 16 longitudinal rows of scales on 73 to 76 retrorse body annuli; each scale bearing five to seven sharply pointed processes; one lip annulus with an equal diameter to first body annulus. O^ma ueckermanni spec. nov. females are characterised by eight longitudinal rows of rounded scales on 60 to 67 body annuli becoming longer toward tail tip where they bear two, three or four-pronged processes; roughly sculptured recessed part of annulus extends to follow the outline of the scale almost forming a pillar between two succeeding scales; one lip annulus with a greater diameter than first body annulus; raised labial area with six pseudolips and no submedian lobes; margin of lip annulus with rounded tooth-like projections; stylet 49,3 to 60,7 ^m long. A list is given of the 16 known plant-parasitic nematodes found in these areas.


Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1233
Author(s):  
Alemayehu Teressa Negawo ◽  
Meki S. Muktar ◽  
Yilikal Assefa ◽  
Jean Hanson ◽  
Alieu M. Sartie ◽  
...  

Rhodes grass (Chloris gayana Kunth) is one of the most important forage grasses used throughout the tropical and subtropical regions of the world. Enhancing the conservation and use of genetic resources requires the development of knowledge and understanding about the existing global diversity of the species. In this study, 104 Rhodes grass accessions, held in trust in the ILRI forage genebank, were characterized using DArTSeq markers to evaluate the genetic diversity and population structure, and to develop representative subsets, of the collection. The genotyping produced 193,988 SNP and 142,522 SilicoDArT markers with an average polymorphic information content of 0.18 and 0.26, respectively. Hierarchical clustering using selected informative markers showed the presence of two and three main clusters using SNP and SilicoDArT markers, respectively, with a cophenetic correction coefficient of 82%. Bayesian population structure analysis also showed the presence of two main subpopulations using both marker types indicating the existence of significant genetic variation in the collection. A representative subset, containing 21 accessions from diverse origins, was developed using the SNP markers. In general, the results revealed substantial genetic diversity in the Rhodes grass collection, and the generated molecular information, together with the developed subset, should help enhance the management, use and improvement of Rhodes grass germplasm in the future.


2021 ◽  
Vol 5 (1) ◽  
pp. 140-150
Author(s):  
Adebowale Adegboyega Tanimola ◽  
A. O. Asimiea ◽  
G. Uwaoma

Waterleaf, Talinum triangulare is cultivated in home gardens and fields to improve nutritional quality for the family and a source of livelihood for farmers. However, the role of T. triangulare is often counteracted by plant-parasitic nematodes (PPNs). Effective management of PPNs will depend on the identification and determination of their population and distribution. A survey was conducted in two Local Government Areas (LGAs), Ikwerre and Obio-Akpor of Rivers State to identify plant-parasitic nematodes associated with waterleaf. Multistage random sampling technique was employed in the collection of 60 bulked soil and root samples across six waterleaf monoculture farming communities. The nematodes were extracted, identified and their population determined using standard procedures. Occurrences, relative importance values (RIV) and diversity indices were determined. Other data were analysed using descriptive statistics and analysis of variance. Six plant-parasitic nematodes genera were encountered in this study, Helicotylenchus, Pratylenchus, Paratylenchus, Meloidogyne, Scutellonema and Tylenchulus. Pratylenchus and Helicotylenchus were the most frequently occurring nematode pest genera with equal relative frequency of occurrence of 38.89%. Pratylenchus species with RIV of 61.34% was the most important nematode pest associated with waterleaf across the six farm communities. The dominance index of 0.71 for the nematode genera showed that some nematode species dominated others. Alakahia farms had the highest population of plant-parasitic nematodes (2,780) across the six farm communities, whereas Omagwa farms had the lowest (250). The study showed that nematode pests are associated with waterleaf and could be contributing to yield losses in this crop


1969 ◽  
Vol 66 (1) ◽  
pp. 52-59
Author(s):  
D. Oramas ◽  
J. Román

A survey was conducted through the five argricultural regions of Puerto Rico to determine distribution and population density of the nematode species associated with plantain. Fourteen genera, represented by 19 species of phytoparasitic nematodes were found in association with the crop: Ditylenchus, Helicotylenchus, Hoplolaimus, longidorus, Meloidogyne, Paratylenchus, Pratylenchus, Pseudhalenchus, Quinisulcius, Radopholus, Rotylenchulus, Tylenchorhynchus, Tylenchus, and Xiphinema. Meloidogyne incognita, Helicotylenchus spp., Radopholus similis, and Rotylenchulus reniformis were the most widely distributed nematode species throughout the Island. On the other hand, M. incognita, P. coffeae, R. similis, Helicotylenchus spp. , and R. reniformis had higher population densities.


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