Assessing maize diversity and defining a representative subset by means of selected morphological ear traits

2018 ◽  
Vol 16 (6) ◽  
pp. 488-497
Author(s):  
Froylan Rincon-Sanchez ◽  
Norma A. Ruiz-Torres
Keyword(s):  
Morphological Description ◽  
Land Race ◽  
Maize Populations ◽  
Participatory Conservation ◽  
Maize Diversity ◽  
Representative Subset ◽  
Breeding Techniques ◽  
Conservation And Management

AbstractThe objectives of this study were to analyse the maize diversity in the southeast of Coahuila State in Mexico and to identify a representative subset that encompasses the majority of the diversity in the region of study. Seventy-seven native maize populations were first explored and given a race classification followed by a morphological description based on selected quantitative ear traits using 10 representative ears from the collected samples. The differences between maize populations from the adaptation area and the relationships between and within groups in the region of study indicate the usefulness of the ear traits to describe maize diversity. Two main groups were identified that summarized the maize diversity. The first group, the conical ear complex, includes populations adapted to highland altitudes (Conico Norteño Race). The second group, the cylindrical ear complex, represents populations adapted to lowland and intermediate altitudes (Raton and Tuxpeño Norteño). Using the phenogram, a subset of 18 out of the 77 maize populations (23.4%) was defined that accounts for the variation between and within the different race complexes. This subset also includes at least one representative population from each of the less represented types. The final subset, representing a sample of maize diversity, can be used to establish strategies for conservation and use, such as participatory conservation and management, or it can be used to develop breeding techniques for improving the land race populations within the region of study.

scholarly journals Longitudinal analysis of maize diversity in Yucatan, Mexico: influence of agro-ecological factors on landraces conservation and modern variety introduction

2015 ◽  
Vol 15 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Marianna Fenzi ◽  
Devra I. Jarvis ◽  
Luis Manuel Arias Reyes ◽  
Luis Latournerie Moreno ◽  
John Tuxill
Keyword(s):  
Longitudinal Analysis ◽  
Ecological Factors ◽  
Farming Systems ◽  
Fine Grained ◽  
Maize Populations ◽  
Maize Diversity ◽  
Maize Varieties ◽  
Maize Variety ◽  
Hybrid Seeds ◽  
Average Plant

Transformations that farmers bring to their traditional farming systems and their impacts on the conservation and evolution of maize varieties over a 12-year period are investigated using a longitudinal analysis. Despite the increased introduction and supply of improved maize variety seeds in the Yucatan Peninsula, Mexico, over the last 12 years farmers continue to maintain a substantial amount of traditional maize variety diversity. Even with the increased availability of hybrid seeds, farmers in the community of Yaxcaba on average plant more than three quarters of their milpa fields to traditional maize varieties, with the latter one fourth predominately planted to a locally improved varietyNal Xoy, a farm cross of a traditional variety and an improved variety. We observed a significant reduction in yellow –x-Nuuk nal, a long-cycle traditional landrace, paralleled by an increase in short- and intermediate-cycle locally adapted improved maize varieties. We found great differences in the distribution of maize varieties by soil type, with modern varieties being targeted for the rarer, deeper and fine-grained soils, while traditional varieties predominate on the more prevalent stony and thin soils. Our results provide a picture in which most traditional maize varieties in Yaxcaba continue to be maintained by farmers, coexisting with locally adapted improved varieties on the same landscape, and allowing the continued evolution of maize populations.

A scanning electron microscopic study of the veliger larvae of the scallop argopecten purpuratus

1988 ◽  
Vol 46 ◽  
pp. 284-285
Author(s):  
G.C. Bellolio ◽  
K.S. Lohrmann ◽  
E.M. Dupré
Keyword(s):  
Morphological Description ◽  
Electron Microscopic ◽  
Larval Stages ◽  
Scanning Electron Microscopic Study ◽  
The Pacific ◽  
Argopecten Purpuratus ◽  
Veliger Larvae ◽  
20 Nm ◽  
Ethanol Series ◽  
Scanning Electron

Argopecten purpuratus is a scallop distributed in the Pacific coast of Chile and Peru. Although this species is mass cultured in both countries there is no morphological description available of the development of this bivalve except for few characterizations of some larval stages described for culture purposes. In this work veliger larvae (app. 140 pm length) were examined by the scanning electron microscope (SEM) in order to study some aspects of the organogenesis of this species.Veliger larvae were obtained from hatchery cultures, relaxed with a solution of MgCl2 and killed by slow addition of 21 glutaraldehyde (GA) in seawater (SW). They were fixed in 2% GA in calcium free artificial SW (pH 8.3), rinsed 3 times in calcium free SW, and dehydrated in a graded ethanol series. The larvae were critical point dried and mounted on double scotch tape (DST). To permit internal view, some valves were removed by slightly pressing and lifting the tip of a cactus spine wrapped with DST, The samples were coated with 20 nm gold and examined with a JEOL JSM T-300 operated at 15 KV.

Ultrastructure of periplasmic bodies in gram-negative bacteria

1990 ◽  
Vol 48 (3) ◽  
pp. 640-641
Author(s):  
Xie Nianming ◽  
Ding Shaoqing ◽  
Wang Luping ◽  
Yuan Zenglin ◽  
Zhan Guolai ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Campylobacter Jejuni ◽  
Proteus Mirabilis ◽  
Shigella Flexneri ◽  
Morphological Description ◽  
Gram Negative Bacteria ◽  
Periplasmic Space ◽  
Clostridium Tetani ◽  
Gram Negative ◽  
Brucella Canis

Perhaps the data about periplasmic enzymes are obtained through biochemical methods but lack of morphological description. We have proved the existence of periplasmic bodies by electron microscope and described their ultrastructures. We hope this report may draw the attention of biochemists and mrophologists to collaborate on researches in periplasmic enzymes or periplasmic bodies with each other.One or more independent bodies may be seen in the periplasmic space between outer and inner membranes of Gram-negative bacteria, which we called periplasmic bodies. The periplasmic bodies have been found in seven species of bacteria at least, including the Pseudomonas aeroginosa. Shigella flexneri, Echerichia coli. Yersinia pestis, Campylobacter jejuni, Proteus mirabilis, Clostridium tetani. Vibrio cholerae and Brucella canis.

Inequality in the Promised Land

2020 ◽  
Vol 9 (1) ◽  
pp. 177-180
Author(s):  
Muhammad Sharif Uddin
Keyword(s):  
United States ◽  
Minority Students ◽  
Doctoral Dissertation ◽  
Ethnographic Study ◽  
Suburban Area ◽  
Midwestern United States ◽  
Minority Community ◽  
Promised Land ◽  
Land Race ◽  
The Relationship

Inequality in the promised land: Race, resources, and suburban schooling is a well-written book by L’ Heureux Lewis-McCoy. The book is based on Lewis-McCoy’s doctoral dissertation, that included an ethnographic study in a suburban area named Rolling Acres in the Midwestern United States. Lewis-McCoy studied the relationship between families and those families’ relationships with schools. Through this study, the author explored how invisible inequality and racism in an affluent suburban area became the barrier for racial and economically minority students to grow up academically. Lewis-McCoy also discovered the hope of the minority community for raising their children for a better future.

Digenean parasites in prosobranch snail Lithoglyphus naticoides population with the morphological description of Echinochasmus sp. cercaria

Ekologija ◽  
2008 ◽  
Vol 54 (4) ◽  
pp. 251-255 ◽  
Author(s):  
Gražina Stanevičiūtė ◽  
Romualda Petkevičiūtė ◽  
Valerija Kiselienė
Keyword(s):  
Morphological Description ◽  
Prosobranch Snail ◽  
Lithoglyphus Naticoides

`Diet GMKTN55' Offers Accelerated Benchmarking Through a Representative Subset Approach

2018 ◽  
Author(s):  
Tim Gould
Keyword(s):  
Density Functional ◽  
Chem Phys ◽  
Comprehensive Analysis ◽  
Genetic Approach ◽  
Representative Subset ◽  
Phys Chem Chem Phys

The GMTKN55 benchmarking protocol introduced by [Goerigk et al., Phys. Chem. Chem. Phys., 2017, 19, 32184] allows comprehensive analysis and ranking of density functional approximations with diverse chemical behaviours. But this comprehensiveness comes at a cost: GMTKN55's 1500 benchmarking values require energies for around 2500 systems to be calculated, making it a costly exercise. This manuscript introduces three subsets of GMTKN55, consisting of 30, 100 and 150 systems, as `diet' substitutes for the full database. The subsets are chosen via a stochastic genetic approach, and consequently can reproduce key results of the full GMTKN55 database, including ranking of approximations.

Investigation Plan to strengthen the Conservation and Management of Estuary Ecosystems

2020 ◽  
Vol 32 (4) ◽  
pp. 317-334
Author(s):  
Jeong-Cheol Lim ◽  
Kyung-Hwan Ahn ◽  
Byeong-Ki Choi ◽  
Gyeong-Yeon Lee
Keyword(s):  
Conservation And Management

Russian and English terminological glossary on morphology of diatoms

2018 ◽  
Vol 52 (2) ◽  
pp. 265-309 ◽  
Author(s):  
R. M. Gogorev ◽  
D. A. Chudaev ◽  
V. A. Stepanova ◽  
M. S. Kulikovskiy
Keyword(s):  
Morphological Description ◽  
Key Terms

The present work is an attempt to summarize, systematize, supplement and clarify the terms used in morphological description of diatoms and their taxonomy (systematics). Two glossaries (Russian and English) include definitions of near 300 key terms (excluding their synonyms) and their Latin translations.

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