scholarly journals Population Structure of Phytophthora infestans in the Toluca Valley Region of Central Mexico

2001 ◽  
Vol 91 (9) ◽  
pp. 882-890 ◽  
Author(s):  
Niklaus J. Grünwald ◽  
Wilbert G. Flier ◽  
Anne K. Sturbaum ◽  
Edith Garay-Serrano ◽  
Trudy B. M. van den Bosch ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Phytophthora Infestans ◽  
Production Systems ◽  
Allozyme Data ◽  
Land Race ◽  
Disease Occurrence ◽  
Cultivated Potatoes ◽  
Toluca Valley ◽  
Solanum Spp ◽  
Wild Solanum

We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii) modern cultivars in high-input agriculture (VALLEY). Isolates were sampled in 1988-89 (n= 179) and in 1997-98 (n= 389). In both sampling periods, the greatest genetic diversity was observed in RURAL and VALLEY habitats. Based on the Glucose-6-phosphate isomerase and Peptidase allozymes, the subpopulations from the three habitats were significantly differentiated in both sampling periods. In contrast to allozyme data for 1997-98, no differences were found among the three subpopulations for sensitivity to metalaxyl. Two groups of isolates identical for allozyme and mating type were further investigated by restriction fragment length polymorphism fingerprinting; 65% of one group and 85% of another group were demonstrated to be unique. The genetic diversity data and the chronology of disease occurrence during the season are consistent with the hypothesis that populations of P. infestans on wild Solanum populations are derived from populations on cultivated potatoes in the central highlands of Mexico near Toluca.

scholarly journals The Population Structure of Phytophthora infestans from the Toluca Valley of Central Mexico Suggests Genetic Differentiation Between Populations from Cultivated Potato and Wild Solanum spp.

2003 ◽  
Vol 93 (4) ◽  
pp. 382-390 ◽  
Author(s):  
Wilbert G. Flier ◽  
Niklaus J. Grünwald ◽  
Laurens P. N. M. Kroon ◽  
Anne K. Sturbaum ◽  
Trudy B. M. van den Bosch ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Phytophthora Infestans ◽  
Central Mexico ◽  
Commercial Potato ◽  
Cultivated Potatoes ◽  
Toluca Valley ◽  
Solanum Spp ◽  
Mtdna Haplotype ◽  
Wild Solanum

The population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected from cultivated potatoes and the native wild Solanum spp., S. demissum and S. xendinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplified fragment length polymorphism (AFLP) multi-locus fingerprint genotype. Isolate samples were monomorphic for mtDNA haplotype because all isolates tested were of the Ia haplotype. A total of 158 multilocus AFLP genotypes were identified among the 170 P. infestans isolates included in this study. P. infestans populations sampled in the Toluca Valley in 1997 were highly variable and almost every single isolate represented a unique genotype based on the analysis of 165 AFLP marker loci. Populations of P. infestans collected from the commercial potato-growing region in the valley, the subsistence potato production area along the slopes of the Nevado de Toluca, and the native Solanum spp. on the forested slopes of the volcano showed a high degree of genetic diversity. The number of polymorphic loci varied from 20.0 to 62.4% for isolates collected from the field station and wild Solanum spp. On average, 81.8% (135) of the AFLP loci were polymorphic. Hetero-zygosity varied between 7.7 and 19.4%. Significant differentiation was found at the population level between strains originating from cultivated potatoes and wild Solanum spp. (P = 0.001 to 0.022). Private alleles were observed in individual isolates collected from all three populations, with numbers of unique dominant alleles varying from 9 to 16 for isolates collected from commercial potato crops and native Solanum spp., respectively. Four AFLP markers were exclusively found present in isolates collected from S. demissum. Indirect estimation of gene flow between populations indicated restricted gene flow between both P. infestans populations from cultivated potatoes and wild Solanum hosts. There was no evidence found for the presence of substructuring at the subpopulation (field) level. We hypothesize that population differentiation and genetic isolation of P. infestans in the Toluca Valley is driven by host-specific factors (i.e., R-genes) widely distributed in wild Solanum spp. and random genetic drift.

scholarly journals Variation in Genetic Diversity of Phytophthora infestans Populations in Mexico from the Center of Origin Outwards

Plant Disease ◽  
2018 ◽  
Vol 102 (8) ◽  
pp. 1534-1540 ◽  
Author(s):  
Shankar K. Shakya ◽  
Meredith M. Larsen ◽  
Mercedes María Cuenca-Condoy ◽  
Héctor Lozoya-Saldaña ◽  
Niklaus J. Grünwald
Keyword(s):  
Genetic Diversity ◽  
Phytophthora Infestans ◽  
The Other ◽  
Sampling Location ◽  
Linkage Equilibrium ◽  
Geographical Distance ◽  
Significant Genetic Differentiation ◽  
Center Of Origin ◽  
Toluca Valley ◽  
Late Blight Pathogen

The Toluca valley, located in central Mexico, is thought to be the center of origin of the potato late blight pathogen Phytophthora infestans. We characterized over 500 individuals of P. infestans sampled from populations with a geographical distance of more than 400 km in six regions adjacent to the Toluca valley in three states including Michoacán, Mexico, and Tlaxcala. Our sampling occurred on a predominant east to west gradient and showed significant genetic differentiation. The most western sampling location found in Michoacán was most differentiated from the other populations. Populations from San Gerónimo, Juchitepec, and Tlaxcala clustered together and appeared to be in linkage equilibrium. This work provides a finer understanding of gradients of genetic diversity in populations of P. infestans at the center of origin.

scholarly journals Multi-genotype varieties reduce rice diseases through enhanced genetic diversity and show stability and adaptability in the field

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Ping He ◽  
Cong Wang ◽  
Neng Zhang ◽  
Bin Liu ◽  
Yang Yang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Disease Resistance ◽  
Agricultural Development ◽  
Production Systems ◽  
Field Trials ◽  
Blast Disease ◽  
Rice Varieties ◽  
Rice Plants ◽  
Disease Occurrence ◽  
The Relationship

AbstractRice is a crucial food crop worldwide. The genetic diversity in rice germplasm indicates its promising potential utilization in disease and pest control. To explore the relationship between genetic diversity and disease resistance in rice plants, multi-genotype rice varieties developed from multi-parent advanced generation inter-cross (MAGIC) population lines were used here to analyze the correlation between disease occurrence and genetic diversity, as well as for field monitoring of their disease occurrences and yields. We found that genetic diversity and disease resistance of the multi-genotype varieties tested in this study were superior to those of their component lines and mono-genotype varieties, and the incidence of rice blast disease decreased as the genetic diversity of multi-genotype rice varieties increased. We further conducted field trials using these multi-genotype varieties for three years in different rice-planting areas. The results showed that multi-genotype varieties exhibited good disease resistance and high-yielding potential. Thus, proper use of multi-genotype varieties characterized by rich genetic diversity is a promising approach to improve disease resistance of rice plants in agricultural production systems and is of great significance for ensuring food security and achieving sustainable agricultural development.

scholarly journals Testing Taxonomic Predictivity of Foliar and Tuber Resistance to Phytophthora infestans in Wild Relatives of Potato

2015 ◽  
Vol 105 (9) ◽  
pp. 1198-1205 ◽  
Author(s):  
A. Khiutti ◽  
D. M. Spooner ◽  
S. H. Jansky ◽  
D. A. Halterman
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Breeding System ◽  
Host Resistance ◽  
Late Blight Resistance ◽  
Wild Relatives ◽  
Blight Resistance ◽  
Tuber Resistance ◽  
Solanum Spp ◽  
Wild Solanum

Potato late blight, caused by the oomycete phytopathogen Phytophthora infestans, is a devastating disease found in potato-growing regions worldwide. Long-term management strategies to control late blight include the incorporation of host resistance to predominant strains. However, due to rapid genetic changes within pathogen populations, rapid and recurring identification and integration of novel host resistance traits is necessary. Wild relatives of potato offer a rich source of desirable traits, including late blight resistance, but screening methods can be time intensive. We tested the ability of taxonomy, ploidy, crossing group, breeding system, and geography to predict the presence of foliar and tuber late blight resistance in wild Solanum spp. Significant variation for resistance to both tuber and foliar late blight was found within and among species but there was no discernable predictive power based on taxonomic series, clade, ploidy, breeding system, elevation, or geographic location. We observed a moderate but significant correlation between tuber and foliar resistance within species. Although previously uncharacterized sources of both foliar and tuber resistance were identified, our study does not support an assumption that taxonomic or geographic data can be used to predict sources of late blight resistance in wild Solanum spp.

scholarly journals Mitochondrial Genetic Diversity among Farmed Stocks of Oreochromis spp. (Perciformes, Cichlidae) in Madagascar

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 281
Author(s):  
Nicolas Hubert ◽  
Elodie Pepey ◽  
Jean-Michel Mortillaro ◽  
Dirk Steinke ◽  
Diana Edithe Andria-Mananjara ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Low Income ◽  
Food System ◽  
Production Systems ◽  
Dna Barcode ◽  
Diversity Indices ◽  
Low Income Countries ◽  
Wild Populations ◽  
Fast Development ◽  
Well Differentiated

The fast development of aquaculture over the past decades has made it the main source of fish protein and led to its integration into the global food system. Mostly originating from inland production systems, aquaculture has emerged as strategy to decrease malnutrition in low-income countries. The Nile tilapia (Oreochromis niloticus) was introduced to Madagascar in the 1950s, and is now produced nationally at various scales. Aquaculture mostly relies on fry harvested from wild populations and grow-out in ponds for decades. It has recently been diversified by the introduction of several fast-growing strains. Little is known how local genetic diversity compares to recently introduced strains, although high and comparable levels of genetic diversity have previously been observed for both wild populations and local stocks. Our study compares DNA barcode genetic diversity among eight farms and several strains belonging to three species sampled. DNA-based lineage delimitation methods were applied and resulted in the detection of six well differentiated and highly divergent lineages. A comparison of DNA barcode records to sequences on the Barcode of Life Data System (BOLD) helped to trace the origin of several of them. Both haplotype and nucleotide diversity indices highlight high levels of mitochondrial genetic diversity, with several local strains displaying higher diversity than recently introduced strains. This allows for multiple options to maintain high levels of genetic diversity in broodstock and provides more options for selective breeding programs.

scholarly journals The presence of Phytophthora infestans in the rhizosphere of a wild Solanum species may contribute to off-season survival and pathogenicity

2020 ◽  
Vol 148 ◽  
pp. 103475 ◽  
Author(s):  
Ramesh R. Vetukuri ◽  
Laura Masini ◽  
Rebecca McDougal ◽  
Preeti Panda ◽  
Levine de Zinger ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Solanum Species ◽  
Wild Solanum Species ◽  
Wild Solanum

Forest Conservation Genetics

2000 ◽  
Author(s):  
Andrew Young ◽  
David Boshier ◽  
Timothy Boyle
Keyword(s):  
Genetic Diversity ◽  
Conservation Genetics ◽  
Undergraduate Students ◽  
Sustainable Management ◽  
Forest Conservation ◽  
Production Systems ◽  
Management Strategies ◽  
Management Policy ◽  
Tropical Regions ◽  
Logical Sequence

Forest management must be sustainable not only in ecological, economic and social, but also genetic terms. Many forest managers are advocating and developing management strategies that give priority to conserving genetic diversity within production systems, or that recognise the importance of genetic considerations in achieving sustainable management. Forest Conservation Genetics draws together much previously uncollected information relevant to managing and conserving forests. The content emphasises the importance of conserving genetic diversity in achieving sustainable management. Each chapter is written by a leading expert and has been peer reviewed. Readers without a background in genetics will find the logical sequence of topics allows easy understanding of the principles involved and how those principles may impact on day-to-day forest planning and management decisions. The book is primarily aimed at undergraduate students of biology, ecology, forestry, and graduate students of forest genetics, resource management policy and/or conservation biology. It will prove useful for those teaching courses in these fields and as such help to increase the awareness of genetic factors in conservation and sustainable management, in both temperate and tropical regions.

POPULATION SUBSTRUCTURING OF PHYTOPHTHORA INFESTANS ON AMERICAN POTATO CLONES IN THE TOLUCA VALLEY, MÉXICO

2003 ◽  
pp. 183-188
Author(s):  
H. Lozoya-Saldaña ◽  
N.J. Grünwald ◽  
C. Brown ◽  
E. Garay-Serrano ◽  
A. Sturbaum-Abud ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Population Substructuring ◽  
Toluca Valley
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