Cytogenetic and isozyme studies of wild and cultivated Capsicum annuum

The esterase isozymes of 15 wild and cultivated accessions of Capsicum annuum from different geographic areas throughout the United States, Mexico, Central America, and South America showed three patterns. All accessions from central Mexico, including the cultivated type, and some from the United States, had pattern A. Other accessions from the United States, those from Central America, and those from Peru had pattern B; those from Colombia had pattern C. Pattern C had more bands, apparently identical with those in the hybrids between A and B. F1 plants between the Colombian accession used in a hybridization test and accessions with patterns A and B showed associations of four or six chromosomes at metaphase I of meiosis. The hypothesis is discussed that pattern C resulted from a process of gene duplication. The alternative explanation of permanent translocation heterozygosity is excluded because in the Colombian accessions no multivalents were observed at meiosis.Key words: Capsicum, geographic distributions, duplication, translocation, isozymes.

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A BIOSYSTEMATIC REVISION OF THE GENUS MUSCIDIFURAX (HYMENOPTERA: PTEROMALIDAE) WITH DESCRIPTIONS OF FOUR NEW SPECIES

The Canadian Entomologist ◽

10.4039/ent1021268-10 ◽

1970 ◽

Vol 102 (10) ◽

pp. 1268-1290 ◽

Cited By ~ 51

Author(s):

Marcos Kogan ◽

E. F. Legner

Keyword(s):

United States ◽

Puerto Rico ◽

Central America ◽

New World ◽

The United States ◽

Additional Species ◽

Local Populations ◽

Morphological Studies ◽

Scanning Electronmicroscopy ◽

United States Mexico

AbstractExtensive collections of synanthropic fly parasitoids in animal excrement accumulations in the United States, Mexico, Costa Rica, Puerto Rico, Uruguay, Chile, Denmark, Israel, and South Africa yielded seven forms of a Muscidifurax complex which were totally or partially reproductively isolated. Morphological studies of female and male parasitoids coupled with biological and zoogeographical information permitted the identification of five sibling species. Muscidifurax raptor Girault and Sanders 1910 is redescribed and four additional species are described as new: M. zaraptor, from the southwestern United States; M. raptoroides from Central America and Mexico; M. uniraptor from Puerto Rico, and M. raptorellus from Uruguay and Chile. Biological notes are added to the descriptions, and it was postulated that the genus is undergoing a process of speciation with local populations slowly becoming reproductively isolated and eventually giving rise to morphologically distinguishable entities. Most evidence suggests the establishment of Muscidifurax in the New World, concomitant with or shortly following the establishment of muscoid flies in accumulated excrement. Scanning electronmicroscopy was used in the analysis of some morphological structures.

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Frost tolerance of Liquidambar styraciflua native to the United States, Mexico, and Central America

Canadian Journal of Botany ◽

10.1139/b71-218 ◽

1971 ◽

Vol 49 (9) ◽

pp. 1551-1558 ◽

Cited By ~ 5

Author(s):

George J. Williams, III ◽

Calvin McMillan

Keyword(s):

United States ◽

Central America ◽

The United States ◽

Frost Tolerance ◽

Liquidambar Styraciflua ◽

United States Mexico ◽

Amo 1618 ◽

The U.S ◽

Collection Sites ◽

Selection Of

Seedlings derived from field-collected seed from the United States, Mexico, and Central America were tested for frost hardiness under laboratory conditions. U.S. seedlings grown under four controlled conditions demonstrated greatest frost hardening under cool temperatures and short day lengths. Seedlings representing northernmost U.S. collection sites developed greater frost tolerance than seedlings representing southern U.S. collection sites. In comparing United States, Mexico, and Central America seedlings, the U.S. material showed greatest frost tolerance with Mexico and Central America demonstrating similar hardiness. The application of plant hormones (natural gibberellic acid and artificial AMO-1618) produced opposite effects on U.S. seedlings derived from Connecticut and Florida seed. The Connecticut seedlings demonstrated greatest frost tolerance in all treatments. Demonstrated frost tolerance differences among United States, Mexico, and Central America populations strongly indicate selection of frost hardy races in habitats with severe frost conditions.

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Synthesis of Results from the North American Monsoon Experiment (NAME) Process Study

Journal of Climate ◽

10.1175/jcli4081.1 ◽

2007 ◽

Vol 20 (9) ◽

pp. 1601-1607 ◽

Cited By ~ 53

Author(s):

Wayne Higgins ◽

David Gochis

Keyword(s):

United States ◽

Central America ◽

North American ◽

The United States ◽

Background Information ◽

North American Monsoon ◽

The North ◽

Process Study ◽

Monsoon System ◽

United States Mexico

Abstract An international team of scientists from the United States, Mexico, and Central America carried out a major field campaign during the summer of 2004 to develop an improved understanding of the North American monsoon system leading to improved precipitation forecasts. Results from this campaign, which is the centerpiece of the North American Monsoon Experiment (NAME) Process Study, are reported in this issue of the Journal of Climate. In addition to a synthesis of key findings, this brief overview article also raises some important unresolved issues that require further attention. More detailed background information on NAME, including motivating science questions, where NAME 2004 was conducted, when, and the experimental design, was published previously by Higgins et al.

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Resistance to Candidatus Liberibacter solanacearum in tomato landraces from Mexico

10.1101/605188 ◽

2019 ◽

Author(s):

José A. Garzón-Tiznado ◽

Carlos A. López-Orona ◽

Luciano Castro-Espinoza ◽

Sixto Velarde-Félix ◽

Marely G. Figueroa-Pérez ◽

...

Keyword(s):

United States ◽

New Zealand ◽

Central America ◽

Incubation Time ◽

Plant Pathogen ◽

The United States ◽

Resistant Cultivars ◽

Wide Range ◽

Resistant Sources ◽

United States Mexico

AbstractCandidatus Liberibacter solanacearum (CLso) is an economically important plant-pathogen of tomato (Solanum lycopersicum) crops in the United States, Mexico, Central America, and New Zealand. Currently, there are no reports of resistance to CLso in tomato cultivars. Identification and development of CLso-resistant cultivars may offer the most efficient way to manage this tomato disease. Resistance of 46 tomato landraces collected in different regions of Mexico, representing a wide range of genetic variability from this country was evaluated. Two assays were done in consecutively years to assess the resistance to CLso under greenhouse conditions. Plants from both tests were inoculated with CLso through 20 Bactericera cockerelli insects per plant. In the first trial, landraces FC22 and FC44 showed a significantly higher proportion of resistant plants, less symptoms severity, and longer incubation time, followed by landraces FC40 and FC33 compared with the rest of the 42 landraces and 2 susceptible cultivars 60 days post inoculation (dpi). In the second assay, only landraces FC22 and FC44 had again significantly higher proportion of resistant plants, less symptoms severity, relative lower CLso titers, and longer incubation time in comparison with landraces FC40 and FC33 and the two susceptible cultivars 60 dpi, corroborating their resistance to CLso. Presence of CLso DNA in all resistant plants from both assays discards scape plants and indicates that the methodology used was adequate to discriminate between resistant and susceptible plants. These results confirm that landraces FC22 and FC44 are promising resistant sources for the development of CLso-resistant cultivars of tomato.Author summaryThe bacterium “Candidatus Liberibacter solanacearum” (CLso) is an important plant-pathogen of tomato crops in the United States, Mexico, Central America, and New Zealand. Tomato growers are lacking of cultivars with resistance to this pathogen and the development of resistant cultivars of this crop would make a sustainable business for these growers and healthy tomato consumption for humans. Tomato landraces from countries that are center of domestication of cultivated crops like Mexico, are potentially sources of resistance to plant-pathogens. Therefore, two tests were done looking for resistance sources to this pathogen and we found two tomato landraces (FC22 and FC44) showing high level of resistance to CLso because they had significantly higher resistant plants, less symptoms severity, lower CLso DNA concentration, and delay of the first symptoms in the inoculated plants in comparison with the two commercial cultivars and 44 tomato landraces collected from Mexico 60 days post infection. These landraces are promising resistant sources for the development of CLso-resistant cultivars of tomato.

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