Intraracial variation in Phytophthora infestans, and its relationship to different host varieties

1969 ◽  
Vol 47 (6) ◽  
pp. 863-867 ◽  
Author(s):  
Alan Upshall
Keyword(s):  
Growth Rate ◽  
Comparative Study ◽  
Phytophthora Infestans ◽  
Resistant Variety ◽  
Rate Variation ◽  
Low Field

A comparative study of the magnitude of growth rate variation among isolates of Phytophthora infestans (Mont.) de Bary taken from a high and a low field resistant variety of potato has shown it to be greater in the former than in the latter, even though both crops were infected by the same population of the pathogen. Competition between spores, and adaptation to the varieties, are put forward as possible alternative explanations.

ФОРМИРОВАНИЕ ПЕРЕХОДНОГО СЛОЯ ALN НА ТЕМПЛЕЙТАХ 3С-SIC/SI(111) МЕТОДОМ АММИАЧНОЙ МОЛЕКУЛЯРНО-ЛУЧЕВОЙ ЭПИТАКСИИ

2020 ◽  
Vol 96 (3s) ◽  
pp. 148-153
Author(s):  
С.Д. Федотов ◽  
А.В. Бабаев ◽  
В.Н. Стаценко ◽  
К.А. Царик ◽  
В.К. Неволин
Keyword(s):  
Crystal Structure ◽  
Growth Rate ◽  
Low Temperature ◽  
Surface Morphology ◽  
Single Crystal ◽  
Root Mean Square Roughness ◽  
Rate Variation ◽  
Mean Square ◽  
Nucleation Layer ◽  
Low Temperature Epitaxy

Представлены результаты изучения морфологии поверхности и структуры слоев AlN, сформированных аммиачной МЛЭ на темплейтах 3C-SiC/Si(111) on-axis- и 4° off-axis-разориентации. Опробован технологический режим низкотемпературной эпитаксии зародышевого слоя AlN на поверхности 3C-SiC(111). Среднеквадратичная шероховатость поверхности (5 х 5 мкм) слоев AlN толщиной 150 ± 50 нм составила 2,5-3,5 нм на темплейтах 3C-SiC/Si(111) on-axis и 3,3-3,5 нм на 4° off-axis. Показано уменьшение шероховатости смачивающего слоя AlN при изменении скорости роста. Получены монокристаллические слои AlN(0002) со значениями FWHM (ω-геометрия) 1,4-1,6°. The paper presents the surface morphology and crystal structure of AlN layers formed by ammonia MBE on 3C-SiC/Si(111) on-axis and 4° off-axis disorientation. It offers the technological approach of low-temperature epitaxy of the AlN nucleation layer on the 3C-SiC (111) surface. Root mean square roughness (5 х 5 |xm) of AlN layers with thickness of 150 ± 50 nm was 2,5-3,5 nm onto on-axis templates and 3.3-3.5 nm onto 4° off-axis. It appears that the RMS roughness of the AlN surface is changing with the growth rate variation. Single-crystal AlN(0002) layers with FWHM values (ω-geometry) of 1.4-1.6° have been obtained.

Disentangling the role of competition, light interception, and functional traits in tree growth rate variation in South Asian tropical moist forests

2021 ◽  
Vol 483 ◽  
pp. 118908
Author(s):  
Mizanur Rahman ◽  
Masum Billah ◽  
Md Obydur Rahman ◽  
Debit Datta ◽  
Muhammad Ahsanuzzaman ◽  
...  
Keyword(s):  
Growth Rate ◽  
Functional Traits ◽  
South Asian ◽  
Tree Growth ◽  
Light Interception ◽  
Rate Variation ◽  
Tree Growth Rate

scholarly journals Feed demand behavior in sea bass juveniles: Effects on individual specific growth rate variation and health (inter-individual and inter-group variation)

Aquaculture ◽  
2008 ◽  
Vol 274 (1) ◽  
pp. 87-95 ◽  
Author(s):  
S. Millot ◽  
M.-L. Bégout ◽  
J. Person-Le Ruyet ◽  
G. Breuil ◽  
C. Di-Poï ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Sea Bass ◽  
Rate Variation ◽  
Group Variation

A comparative study on the nursery culture of hatchery-reared sub-adult cupped oyster, Crassostrea iredalei (Faustino, 1932), in an earthen pond and a mangrove canal

2018 ◽  
Vol 26 (4) ◽  
pp. 217-222
Author(s):  
Premwadee Chueachat ◽  
Woraporn Tarangkoon ◽  
Suwat Tanyaros
Keyword(s):  
Growth Rate ◽  
Comparative Study ◽  
Condition Index ◽  
Daily Growth ◽  
Nursery Culture ◽  
Absolute Growth Rate ◽  
Significant Difference ◽  
Adult Oyster ◽  
Absolute Growth ◽  
The Mean

Abstract A comparative study on the nursery culture of the spat of the tropical oyster, Crassostrea iredalei, in an earthen pond and a mangrove canal was conducted over two months. The results revealed no differences in the absolute growth rate determined by shell width between the two culture sites (P < 0.05). Sub-adult oysters cultured in the mangrove canal showed a higher absolute growth rate in shell length and a higher daily growth rate than the oysters cultured in the earthen pond (P < 0.05). The mean survival rate of sub-adult oysters cultured in the earthen pond (99.8 ± 0.2%) was significantly higher than for those cultured in the mangrove canal (66.7 ± 31.4%). Decreased density from the loss of sub-adult oyster nursery culture in the mangrove canal led to higher growth performance than in the earthen pond. However, no difference was found for the fraction of oysters larger or smaller than 5 cm for the two culture sites (P < 0.05). A significant difference was noted in the Condition Index (CI) between the two culture sites (P < 0.05). The high primary productivity in mangroves is a major supporter of higher CI in sub-adult oysters cultured in mangrove canals versus in earthen ponds. Water exchange in the earthen pond to maintain calcium and magnesium concentrations resulted in no differences in the shell compressibility of sub-adult oysters compared with those cultured in the mangrove canal.

scholarly journals Beyond demographic buffering: Context dependence in demographic strategies across animals

2021 ◽  
Author(s):  
Omar Lenzi ◽  
Arpat Ozgul ◽  
Roberto Salguero-Gomez ◽  
Maria Paniw
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Temporal Variation ◽  
Population Growth Rate ◽  
Natural Populations ◽  
Environmental Context ◽  
Context Dependence ◽  
Vital Rate ◽  
Rate Variation ◽  
Vital Rates

Temporal variation in vital rates (e.g., survival, reproduction) can decrease the long-term mean performance of a population. Species are therefore expected to evolve demographic strategies that counteract the negative effects of vital rate variation on the population growth rate. One key strategy, demographic buffering, is reflected in a low temporal variation in vital rates critical to population dynamics. However, comparative studies in plants have found little evidence for demographic buffering, and little is known about the prevalence of buffering in animal populations. Here, we used vital rate estimates from 31 natural populations of 29 animal species to assess the prevalence of demographic buffering. We modeled the degree of demographic buffering using a standard measure of correlation between the standard deviation of vital rates and the sensitivity of the population growth rate to changes in such vital rates across populations. We also accounted for the effects of life-history traits, i.e., age at first reproduction and spread of reproduction across the life cycle, on these correlation measures. We found no strong or consistent evidence of demographic buffering across the study populations. Instead, key vital rates could vary substantially depending on the specific environmental context populations experience. We suggest that it is time to look beyond concepts of demographic buffering when studying natural populations towards a stronger focus on the environmental context-dependence of vital-rate variation.

scholarly journals Uji Ketahanan Klon Kentang Hasil Pesilangan Atlantic x Repita terhadap Penyakit Hawar Daun Phytophthora infestans

Agrikultura ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 100
Author(s):  
Helmi Kurniawan ◽  
Ineu Sulastrini ◽  
Tarkus Suganda
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Field Test ◽  
Block Design ◽  
Environmentally Friendly ◽  
Statistical Test ◽  
The Other ◽  
Resistant Variety ◽  
Resistance Level ◽  
Randomized Block Design

ABSTRACTResistance Test of Potato Clones Derived from Crossing of Atlantic x Repita to Late Blight (Phytophthora infestans)Late blight, incited by Phytophthora infestans is the most destructive disease of potato. The management that is effective and environmentally-friendly is the use of resistant variety. The objective of this study was to test the resistance of the six potato clones (AR 04, AR 05, AR 06, AR 07, AR 08 and AR 09) derived from crossing var. Atlantic x var. Repita to late blight caused by P. infestans. Var. Atlantic, Repita and Granola were used as susceptible, resistant and susceptible but the most-grown variety, respectively. Field test was located in Ciwidey, one of the potato growing center where late blight is endemic since potatoes are continuously grown. The treatments were arranged in a randomized block design with 3 replicates. The result showed that clones AR 07 and AR 08 were more resistant than the other potato clones, but it still below the resistance level var. Repita. However, based on statistical test on the diseases development (AUDPC), clone AR 08 could be categorized as resistant, equal with of the resistance level of var. Repita.Keywords: Potato clones, Rsistance, P. infestansABSTRAKPenyakit hawar daun yang disebabkan Phytopthora infestans merupakan penyakit utama pada tanaman kentang. Pengendalian yang efektif dan ramah lingkungan adalah dengan penanaman varietas tahan. Penelitian ini bertujuan untuk menguji ketahanan 6 klon kentang (AR 4, AR5, AR6, AR7, AR 8, dan AR9) yang merupakan hasil persilangan antara var. Atlantic (produksi tinggi tetapi rentan) dengan var. Repita, sebagai tetua tahan terhadap penyakit hawar daun yang disebabkan oleh P. infestans. Varietas Atlantic, Repita dan Granola digunakan sebagai pembanding. Pengujian ketahanan dilakukan di Ciwidey, yang merupakan salah satu sentra produksi kentang di Jawa Barat dan endemik penyakit hawar daun. Perlakuan ditata menggunakan Rancangan Acak Kelompok dengan 3 ulangan. Hasil penelitian menunjukkan bahwa klon AR 07 dan Klon AR 08 memiliki ketahanan yang lebih baik dibanding klon-klon kentang lainnya, namun tingkat ketahanannya masih di bawah cv Repita. Namun, berdasarkan uji statistik terhadap nilai perkembangan penyakit (AUDPC) klon AR 08 dapat dikategorikan tahan, sama dengan derajat tahan var. Repita.Kata Kunci: Klon kentang, Ketahanan, P. infestans

scholarly journals Age and growth rate variation influence the functional relationship between somatic and otolith size

2017 ◽  
Vol 74 (5) ◽  
pp. 680-692 ◽  
Author(s):  
Eloïse C. Ashworth ◽  
Norman G. Hall ◽  
S. Alex Hesp ◽  
Peter G. Coulson ◽  
Ian C. Potter
Keyword(s):  
Growth Rate ◽  
Age And Growth ◽  
Growth Effect ◽  
Parameter Estimates ◽  
Rate Variation ◽  
Fish Length ◽  
Correlated Errors ◽  
Otolith Growth ◽  
Positive Dependence ◽  
Otolith Size

Curves describing the length–otolith size relationships for juveniles and adults of six fish species with widely differing biological characteristics were fitted simultaneously to fish length and otolith size at age, assuming that deviations from those curves are correlated rather than independent. The trajectories of the somatic and otolith growth curves throughout life, which reflect changing ratios of somatic to otolith growth rates, varied markedly among species and resulted in differing trends in the relationships formed between fish and otolith size. Correlations between deviations from predicted values were always positive. Dependence of length on otolith growth rate (i.e., “growth effect”) and “correlated errors in variables” introduce bias into parameter estimates obtained from regressions describing the allometric relationships between fish lengths and otolith sizes. The approach taken in this study to describe somatic and otolith growth accounted for both of these effects and that of age to produce more reliable determinations of the length–otolith size relationships used for back-calculation and assumed when drawing inferences from sclerochronological studies.

scholarly journals Age, Growth and Death of a National Icon: The Historic Chapman Baobab of Botswana

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 983 ◽  
Author(s):  
Adrian Patrut ◽  
Stephan Woodborne ◽  
Roxana T. Patrut ◽  
Grant Hall ◽  
Laszlo Rakosy ◽  
...  
Keyword(s):  
Growth Rate ◽  
Radiocarbon Dating ◽  
Radiocarbon Date ◽  
Rate Variation ◽  
The Past ◽  
Open Ring ◽  
Climate Evolution ◽  
National Icon ◽  
Ring Shaped Structure ◽  
Past 1000 Years

The year 2016 witnessed the fall of a symbol of the botanical world: the historic Chapman baobab of Botswana. This article presents the results of our investigation of the standing and fallen tree. The Chapman baobab had an open ring-shaped structure composed of six partially fused stems. Several wood samples collected from the stems prior and after their collapse were analysed by using radiocarbon dating. The radiocarbon date of the oldest sample was 1381 ± 22 BP, which corresponds to a calibrated age of 1345 (+10, −15) calendar years. The dating results show that the six stems of the Chapman baobab belonged to three different generations, which were 1350–1400, 800–1000 and 500–600 years old. The growth rate variation of the largest and oldest stem is presented and correlated with the climate evolution in the area over the past 1000 years. The factors that determined the sudden fall and death of the Chapman baobab are also presented and discussed.

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