An Artificial Simulation of the Vernal Increase in Day Length and Its Effects on the Reproductive System in Three Species of Tits (Parus spp.), and Modifying Effects of Environmental Factors: A Field Experiment

The Condor ◽  
1989 ◽  
Vol 91 (3) ◽  
pp. 598 ◽  
Author(s):  
B. Silverin ◽  
P. A. Viebke ◽  
J. Westin
2018 ◽  
Vol 98 (5) ◽  
pp. 1109-1118 ◽  
Author(s):  
Mervi M. Seppänen ◽  
Ville Alitalo ◽  
Hanna K. Bäckström ◽  
Kirsi Mäkiniemi ◽  
Venla Jokela ◽  
...  

Alfalfa (Medicago sativa L.) is one of the most popular forage legume crops worldwide. Its cultivation in the boreal and sub-boreal zone is restricted by inadequate winter hardiness, but global warming may increase its adaptability in these latitudes. Here, we examined variation in growth and freezing tolerance of four alfalfa cultivars recommended for the northern temperate climates of Europe (Alexis, Lavo, Live, and Nexus) and two cultivars with adaptation to milder or Mediterranean climates (Rangelander and Hunter River). Two experiments under controlled conditions (growth cessation and cold acclimation experiments) along with a 2-yr field experiment were conducted. Lavo was the most freezing-tolerant cultivar in both the cold acclimation and field experiments. Both Rangelander and Hunter River showed poor freezing tolerance. Lavo responded to decreasing temperatures, unlike the response to shorter day length, by allocating biomass to the roots. In general, better freezing tolerance was associated with high total nonstructural carbohydrate and low starch content. The field experiment results revealed that the more freezing-tolerant cultivars may have some advantages regarding yield, especially in the second year, but the differences between the cultivars were modest.


1966 ◽  
Vol 44 (2) ◽  
pp. 149-159 ◽  
Author(s):  
Syed Nazar Ahsan

The cyclical changes in the activity of the testes of a teleost, the lake chub, from a north temperate latitude have been studied by histological and histochemical methods with a quantitative evaluation of the different spermatogenetic stages. The annual testicular cycle is divided into live stages and cyclical changes in the spermatogenetic activity have been related to the changing environmental factors, namely day length and water temperature. The annual cycle consists of a prolonged mitotic phase during the fall and winter, and a shorter meiotic phase during the spring. Lobule boundary cells have been examined and changes in their activity have been recorded. Continued spermatogenetic activity during spawning enables repeated spermiation, which is advantageous since the males are comparatively fewer than the females.


2020 ◽  
Author(s):  
Qing Yang ◽  
Gaoming Lin ◽  
Huiyong Lv ◽  
Cunhu Wang ◽  
Yongqing Yang ◽  
...  

Abstract Background: Shoot architecture is fundamentally crucial to crop growth and productivity. As a key component of shoot architecture, plant height is known to be controlled by both genetic and environmental factors, though specific details remain scarce.Results: In this study, 308 representative soybean lines from a core collection and 168 F9 soybean progeny were planted at distinct field sites. The results demonstrated the presence of significant genotype × environment interaction (G × E) effects on traits associated with plant height in a natural soybean population. In total, 19 loci containing 51 QTLs (quantitative trait locus) for plant height were identified across four environments, with 23, 13 and 15 being QTLs for SH (shoot height), SNN (stem node number) and AIL (average internode length), respectively. Significant LOD ranging from 2.50 to 16.46 explained 2.80% - 26.10% of phenotypic variation. Intriguingly, only two loci, Loc11 and Loc19-1, containing 20 QTLs, were simultaneously detected across all environments. Results from Pearson correlation analysis and PCA (principal component analysis) revealed that each of the five agro-meteorological factors and four soil properties significantly affected soybean plant height traits, and that the corresponding QTLs had additive effects. Among significant environmental factors, AD (average day-length), AMaT (average maximum temperature), pH, and AN (available nitrogen) had the largest impacts on soybean plant height. Therefore, in spite of uncontrollable agro-meteorological factors, soybean shoot architecture might be remolded through combined efforts to produce superior soybean genetic materials while also optimizing soil properties.Conclusions: Overall, the comprehensive set of relationships outlined herein among environment factors, soybean genotypes and QTLs in effects on plant height opens new avenues to explore in work aiming to increase soybean yield through improvements in shoot architecture.


2021 ◽  
Author(s):  
Qing Yang ◽  
Gaoming Lin ◽  
Huiyong Lv ◽  
Cunhu Wang ◽  
Yongqing Yang ◽  
...  

Abstract Background:Shoot architecture is fundamentally crucial to crop growth and productivity. As a key component of shoot architecture, plant height is known to be controlled by both genetic and environmental factors, though specific details remain scarce.Results:In this study, 308 representative soybean lines from a core collection and 168 F9 soybean progeny were planted at distinct field sites. The results demonstrated the presence of significant genotype × environment interaction (G × E) effects on traits associated with plant height in a natural soybean population. In total, 19 loci containing 51 QTLs (quantitative trait locus) for plant height were identified across four environments, with 23, 13 and 15 being QTLs for SH (shoot height), SNN (stem node number) and AIL (average internode length), respectively. Significant LOD ranging from 2.50 to 16.46 explained 2.80% - 26.10% of phenotypic variation. Intriguingly, only two loci, Loc11 and Loc19-1, containing 20 QTLs, were simultaneously detected across all environments. Results from Pearson correlation analysis and PCA (principal component analysis) revealed that each of the five agro-meteorological factors and four soil properties significantly affected soybean plant height traits, and that the corresponding QTLs had additive effects. Among significant environmental factors, AD (average day-length), AMaT (average maximum temperature), pH, and AN (available nitrogen) had the largest impacts on soybean plant height. Therefore, in spite of uncontrollable agro-meteorological factors, soybean shoot architecture might be remolded through combined efforts to produce superior soybean genetic materials while also optimizing soil properties.Conclusions:Overall, the comprehensive set of relationships outlined herein among environment factors, soybean genotypes and QTLs in effects on plant height opens new avenues to explore in work aiming to increase soybean yield through improvements in shoot architecture.


2021 ◽  
Author(s):  
Qing Yang ◽  
Gaoming Lin ◽  
Huiyong Lv ◽  
Cunhu Wang ◽  
Yongqing Yang ◽  
...  

Abstract Background:Shoot architecture is fundamentally crucial to crop growth and productivity. As a key component of shoot architecture, plant height is known to be controlled by both genetic and environmental factors, though specific details remain scarce.Results:In this study, 308 representative soybean lines from a core collection and 168 F9 soybean progeny were planted at distinct field sites. The results demonstrated the presence of significant genotype × environment interaction (G × E) effects on traits associated with plant height in a natural soybean population. In total, 19 loci containing 51 QTLs (quantitative trait locus) for plant height were identified across four environments, with 23, 13 and 15 being QTLs for SH (shoot height), SNN (stem node number) and AIL (average internode length), respectively. Significant LOD ranging from 2.50 to 16.46 explained 2.80% - 26.10% of phenotypic variation. Intriguingly, only two loci, Loc11 and Loc19-1, containing 20 QTLs, were simultaneously detected across all environments. Results from Pearson correlation analysis and PCA (principal component analysis) revealed that each of the five agro-meteorological factors and four soil properties significantly affected soybean plant height traits, and that the corresponding QTLs had additive effects. Among significant environmental factors, AD (average day-length), AMaT (average maximum temperature), pH, and AN (available nitrogen) had the largest impacts on soybean plant height. Therefore, in spite of uncontrollable agro-meteorological factors, soybean shoot architecture might be remolded through combined efforts to produce superior soybean genetic materials while also optimizing soil properties.Conclusions:Overall, the comprehensive set of relationships outlined herein among environment factors, soybean genotypes and QTLs in effects on plant height opens new avenues to explore in work aiming to increase soybean yield through improvements in shoot architecture.


2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Ranjana Jaiwal ◽  
C. M. Chaturvedi

Daily injections of L-dihydroxyphenylalanine (L-DOPA, dopamine precursor) given 4 h after 5-hydroxytryptophan (5-HTP, serotonin precursor) induced inhibitory responses in recrudescing gonad (in the first week of December) of Indian palm squirrel, a seasonally breeding subtropical animal. Other temporal relations (L-DOPA given at 0, 8, 12, 16, and 20 h after 5-HTP administration) did not show any effect on the recrudescing gonad. This inhibitory effect of 4 h was evident under short day length (6 : 18) group but was masked by the increasing day length of nature (NDL, late December onwards) and increased photoperiod of long day group (16 : 8). It is apparent that seasonal testicular recrudescence of Indian palm squirrel during short day length by 4 h relation of 5-HTP and L-DOPA is not a pharmacological effect but actually is an alteration of seasonality in this annually breeding mammal. It seems that endogenous mechanism controlling seasonal testicular recrudescence of Indian palm squirrel is reset by timed daily injections of these neurotransmitter drugs. It is suggested that in spite of different environmental factors (photoperiod, humidity, etc.) used by different species to time their annual reproduction, basic mechanism of seasonality appears to be the same, that is, the temporal synergism of neurotransmitter activity.


1966 ◽  
Vol 2 (1) ◽  
pp. 45-47 ◽  
Author(s):  
G. P. Tewari

SummaryA split-plot field experiment was conducted to investigate the influence of planting dates on the formation of nodules in a variety of cowpea (Paraguay 6). Results indicated that the principal factor influencing both nodulation and yield was day-length, the highest number of effective nodules being produced from the June planting.


2020 ◽  
Vol 20 (S1) ◽  
Author(s):  
Konstantin Kozlov ◽  
Alena Sokolkova ◽  
Cheng-Ruei Lee ◽  
Chau-Ti Ting ◽  
Roland Schafleitner ◽  
...  

Abstract Background Phenology data collected recently for about 300 accessions of Vigna radiata (mungbean) is an invaluable resource for investigation of impacts of climatic factors on plant development. Results We developed a new mathematical model that describes the dynamic control of time to flowering by daily values of maximal and minimal temperature, precipitation, day length and solar radiation. We obtained model parameters by adaptation to the available experimental data. The models were validated by cross-validation and used to demonstrate that the phenology of adaptive traits, like flowering time, is strongly predicted not only by local environmental factors but also by plant geographic origin and genotype. Conclusions Of local environmental factors maximal temperature appeared to be the most critical factor determining how faithfully the model describes the data. The models were applied to forecast time to flowering of accessions grown in Taiwan in future years 2020-2030.


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