Functional and quantitative analysis of seed thermal responses in prostrate knotweed (Polygonum aviculare) and common purslane (Portulaca oleracea)

Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 83-90 ◽  
Author(s):  
B. C. Kruk ◽  
R. L. Benech-Arnold
Keyword(s):  
Quantitative Analysis ◽  
Seedling Emergence ◽  
Screening Method ◽  
Thermal Conditions ◽  
Thermal Time ◽  
Base Temperature ◽  
Emergence Period ◽  
Thermal Range ◽  
Polygonum Aviculare ◽  
Common Purslane

A screening method was used to characterize seed thermal responses of prostrate knotweed and common purslane, two important weeds invading wheat in the humid Pampa. Through this method, it was possible to detect thermal conditions that induce or break dormancy in both species. In addition, we were able to quantify changes in dormancy level in seed populations as a function of time of burial after dispersal, through changes in width of the thermal range within which germination can occur. Plotting the overlap of this thermal range and observed soil temperature throughout the year allowed the prediction of the seedling emergence period. This prediction was in agreement with observed seedling emergence in the field for both species, during 2 consecutive yr. From the analysis carried out under laboratory conditions, it was also possible to estimate required thermal time for germination of the nondormant fraction of the population and the base temperature above which thermal time is accumulated. The results obtained from this study are the basis for the formulation of seed germination models that predict not only the occurrence of seedling emergence in the field, but also the dynamics of germination within those periods.

Evaluation of dormancy and germination responses to temperature inCarduus acanthoides and Anagallis arvensisusing a screening system, and relationship with field-observed emergence patterns

2000 ◽  
Vol 10 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Betina C. Kruk ◽  
Roberto L. Benech-Arnold
Keyword(s):  
Prolonged Exposure ◽  
Seasonal Pattern ◽  
Thermal Conditions ◽  
Thermal Time ◽  
Base Temperature ◽  
Dormancy Release ◽  
Carduus Acanthoides ◽  
Thermal Range ◽  
Dry Storage ◽  
Time Required

AbstractExperiments on the facultative winter annuals Carduus acanthoides and Anagallis arvensis were performed: (i) to determine thermal conditions that induce or release dormancy, (ii) to investigate to what extent changes in dormancy level resulting from those thermal conditions explain the seasonal pattern of emergence of these species, and (iii) to estimate required thermal time and base temperature for the germination of non-dormant seeds. Carduus acanthoides required high temperatures followed by decreasing temperatures for dormancy release; however, low winter temperatures did not induce secondary dormancy as expected for a winter annual. To the contrary, low temperatures stimulated dormancy release in the long term. InA. arvensis, dormancy relief was enhanced by dry storage at 25°C, and the response to low temperature was different depending on moisture conditions. Prolonged exposure to moist-chilling increased the dormancy level of the population, while dry storage at 4°C relieved dormancy. For both species, changes in the thermal range permissive for germination as a result of dormancy modifications explained to a large extent the timing of the emergence periods observed in the field. In neither species did base temperature for germination change with the dormancy level of the population. Thermal time required forgermination ofC. acanthoidesvaried with dormancy, while forA. arvensisseeds it was constant.

Germination response of black nightshade (Solanum nigrum) to temperature and the establishment of a thermal time model

Weed Science ◽  
2021 ◽  
pp. 1-26
Author(s):  
Ziqing Ma ◽  
Hongjuan Huang ◽  
Zhaofeng Huang ◽  
Dongjing Guo ◽  
Muhammad Saeed ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seedling Emergence ◽  
Northern China ◽  
Solanum Nigrum ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Black Nightshade ◽  
Germination Response ◽  
Thermal Time Model

Abstract Black nightshade (Solanum nigrum L.) is one of the worst weeds in crop fields, and it spreads mainly by the dispersal of seeds. Temperature is one of the key environmental factors affecting seed germination. We investigated the seed germination response to temperature in six populations of S. nigrum from mid to northern China and derived mathematical models from germination data. The results showed that S. nigrum seeds exhibit distinct germination responses to temperature within the range of 15 to 35 °C. The optimum temperatures for the populations XJ1600, JL1697 and HLJ2134 were 30 °C, and those for the populations NMG1704, HN2160 and LN2209 were 25 °C, 20 °C and 15 °C, respectively. Based on the nonlinear fitting and thermal time models, the predicted base temperatures of the six populations ranged from 2.3 to 6.4 °C, and the required accumulated growing degree days (GDD) ranged from 50.3 to 106.0 °C·d. The base temperatures and the accumulated GDD for germination differed among populations, and there was a significant negative correlation. HLJ2134 population required a high base temperature and accumulated GDD for germination, indicating that it might highly adapted to a warmer and moister environment. Based on the different germination responses of S. nigrum populations to temperature, the thermal time model reflects an innate relationship between base temperature and accumulated GDD required for initiation of seed germination, which provides a better basis for predicting seedling emergence and the timing for optimal control of S. nigrum under field conditions.

scholarly journals Predicting Seedling Emergence of Three Canarygrass (Phalaris) Species under Semi-Arid Conditions Using Parametric and Non-Parametric Models

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 893
Author(s):  
Carlos Sousa-Ortega ◽  
Aritz Royo-Esnal ◽  
José María Urbano
Keyword(s):  
Field Experiments ◽  
Seedling Emergence ◽  
Parametric Models ◽  
Base Temperature ◽  
Weed Species ◽  
Emergence Period ◽  
Growing Seasons ◽  
Ceiling Temperature ◽  
Base Water Potential ◽  
Non Parametric

The Phalaris genus includes annual weed species such as short-spiked canarygrass (Phalaris brachystachys Link.), little-seed canarygrass (Phalaris minor Retz.) and hood canarygrass (Phalaris paradoxa L.), which are especially problematic in Spain; as such, there is a need to develop models to predict the timing of their emergence. Field experiments were conducted at two different locations during two (2006/07 and 2007/08) and three (from 2005/06 to 2007/08) growing seasons. In both locations, 500 seeds of each Phalaris species were sown each growing season, simulating rain-fed cereal field conditions. In addition, the models were validated with three, four and eight independent experiments for P. brachystachys, P. minor and P. paradoxa, respectively. The emergence period of the three Phalaris species lasted between 31 and 48 days after sowing (DAS), showing two main flushes. The three cardinal points for parametric and non-parametric models were established to be between −1 °C and 1 °C for base temperature, between 9.8 °C and 11.8 °C for optimal temperature and between 21.2 °C and 23.4 °C for ceiling temperature; base water potential was estimated to be between −1 and −1.1 MPa. Both parametric and non-parametric models obtained similar results and were successfully validated in 12 out of 15 independent experiments.

Thermal requirements and germination niche breadth of Polygonum ferrugineum Wedd. from southeastern Brazil

2021 ◽  
pp. 1-7
Author(s):  
Andréa R. Marques ◽  
Ana Letícia B. R. Gonçalves ◽  
Fábio S. Santos ◽  
Diego Batlla ◽  
Roberto Benech-Arnold ◽  
...  
Keyword(s):  
Seed Germination ◽  
Niche Breadth ◽  
Thermal Time ◽  
Southeastern Brazil ◽  
Base Temperature ◽  
Light Conditions ◽  
Thermal Requirements ◽  
Thermal Range ◽  
Thermal Limits ◽  
Ceiling Temperature

Abstract Temperature may regulate seed dormancy and germination and determine the geographical distribution of species. The present study investigated the thermal limits for seed germination of Polygonum ferrugineum (Polygonaceae), an aquatic emergent herb distributed throughout tropical and subtropical America. Seed germination responses to light and temperature were evaluated both before (control) and after stratification at 10, 15 and 20°C for 7, 14 and 28 d. Germination of control seeds was ~50% at 10 and 15°C, and they did not germinate from 20 to 30°C. The best stratification treatment was 7 d at 10°C, where seed germination was >76% in the dark for all temperatures, except at 30°C, and < 60% in light conditions. A thermal time approach was applied to the seed germination results. Base temperature (Tb) was 6.3°C for non-dormant seeds and optimal temperature (To) was 20.6°C, ceiling temperature (Tc (<50)) was 32.8°C, and thermal time requirement for 50% germination was 44.4°Cd. We concluded that a fraction of P. ferrugineum seeds is dormant, has a narrow thermal niche to germinate (10 and 15°C) and that cold stratification (10°C) alleviated dormancy and amplified the thermal range permissive for germination of the species. Consequently, P. ferrugineum is expected to occur in colder environments, for example, at high altitudes. Higher temperatures decrease the probabilities of alleviate dormancy and the ability of their seeds to germinate.

A Thermal Time Model to Predict Corn Poppy (Papaver rhoeas) Emergence in Cereal Fields

Weed Science ◽  
2009 ◽  
Vol 57 (6) ◽  
pp. 660-664 ◽  
Author(s):  
Jordi Izquierdo ◽  
José L. González-Andújar ◽  
Fernando Bastida ◽  
Juan A. Lezaún ◽  
María J. Sánchez del Arco
Keyword(s):  
Seedling Emergence ◽  
Gompertz Model ◽  
Sowing Date ◽  
Control Measures ◽  
Thermal Time ◽  
Base Temperature ◽  
Time Model ◽  
Data Set ◽  
Winter Cereals ◽  
Cereal Fields

Corn poppy is the most abundant broad-leaved weed in winter cereals of Mediterranean climate areas and causes important yield losses in wheat. Knowledge of the temporal pattern of emergence will contribute to optimize the timing of control measures, thus maximizing efficacy. The objectives of this research were to develop an emergence model on the basis of soil thermal time and validate it in several localities across Spain. To develop the model, monitoring of seedling emergence was performed weekly during the growing season in a cereal field located in northeastern Spain, during 3 yr. Cumulative thermal time from sowing date was used as the independent variable for predicting cumulative emergence. The Gompertz model was fitted to the data set of emergences. A base temperature of 1.0 C was estimated through iteration for maximum fit. The model accounted for 91% of the variation observed. Model validation in several localities and years showed general good performance in predicting corn poppy seedling emergence ( values ranging from 0.64 to 0.99 and root-mean-square error from 4.4 to 24.3). Ninety percent emergence was accurately predicted in most localities. Results showed that the model performs with greater reliability when significant rainfall (10 mm) occurs within 10 d after crop sowing. Complemented with in-field scouting, it may be a useful tool to better timing control measures in areas that are homogeneous enough regarding climate and crop management.

Temperature and Water Potential as Parameters for Modeling Weed Emergence in Central-Northern Italy

Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 216-222 ◽  
Author(s):  
Roberta Masin ◽  
Donato Loddo ◽  
Stefano Benvenuti ◽  
Maria Clara Zuin ◽  
Mario Macchia ◽  
...  
Keyword(s):  
Water Potential ◽  
Weed Control ◽  
Seedling Emergence ◽  
Thermal Time ◽  
Base Temperature ◽  
Hydrothermal Time ◽  
Data Set ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
Weed Emergence

Predicting weed emergence dynamics can help farmers to plan more effective weed control. The hydrothermal time concept has been used to model emergence as a function of temperature and water potential. Application of this concept is possible if the specific biological thresholds are known. This article provides a data set of base temperature and water potential of eight maize weeds (velvetleaf, redroot pigweed, common lambsquarters, large crabgrass, barnyardgrass, yellow foxtail, green foxtail, and johnsongrass). For five of these species, two ecotypes from two extreme regions of the predominant maize-growing area in Italy (Veneto and Tuscany), were collected and compared to check possible differences that may arise from using the same thresholds for different populations. Seedling emergence of velvetleaf and johnsongrass were modeled using three different approaches: (1) thermal time calculated assuming 5 C as base temperature for both species; (2) thermal time using the specific estimated base temperatures; and (3) hydrothermal time using the specific, estimated base temperatures and water potentials. All the species had base temperatures greater than 10 C, with the exception of velvetleaf (3.9 to 4.4 C) and common lambsquarters (2.0 to 2.6 C). All species showed a calculated base-water potential equal or up to −1.00 MPa. The thresholds of the two ecotypes were similar for all the studied species, with the exception of redroot pigweed, for which the Veneto ecotype showed a water potential lower than −0.41 MPa, whereas it was −0.62 MPa for the Tuscany ecotype. Similar thresholds have been found to be useful in hydrothermal time models covering two climatic regions where maize is grown in Italy. Furthermore, a comparison between the use of specific, estimated, and common thresholds for modeling weed emergence showed that, for a better determination of weed control timing, it is often necessary to estimate the specific thresholds.

EFFECT OF TEMPORARY COVERING ON EARLY POTATO YIELD IN THE CONDITIONS OF THE MOSCOW REGION

2020 ◽  
pp. 31-38
Author(s):  
MARINA E. DIYKANOVA ◽  
◽  
ALEKSANDR G. LEVSHIN ◽  
IRINA N. GASPARYAN ◽  
NATALIA F. DENISKINA ◽  
...  
Keyword(s):  
Seedling Emergence ◽  
Maximum Yield ◽  
Moscow Region ◽  
Cold Weather ◽  
Test Plot ◽  
Early Potato ◽  
Emergence Period ◽  
Potato Varieties ◽  
Russian State ◽  
Covering Material

In the Moscoww region, frosts are quite probable to return until the fi rst decade of June. To protect potatoes from the returning cold weather, it is possible to use a temporary covering material in the “planting – seedling emergence” period. The authors have studied the use of covering materials on early potato varieties of Udacha, Zhukovsky early, Red Scarlet, Snegir’, and Meteor. Studies have been conducted on the test plot of the Vegetable Growing Department of Russian State Agrarian University – Moscow Timiryazev Agricultural Academy in 2017-2019. Non-woven white and black material of the same density of 17 g/m2 was used for covering. No covering was used in the check variant. The cultivation technology was standard,it included tillage (plowing, spring tillage, and cutting ridges before planting), as well as plant care (inter-row cultivation and hilling-up). Planting was carried out with a single-row potato planter. The earliest emergence of seedlings was observed under white covering material with a diff erence of 5-6 days in relation to the check variant. In the variant with a black covering material, the diff erence averaged 3-4 days. Due to covering, planting was carried out earlier than expected and the crop was formed by July 15. The interphase period between potato planting and seddling emergence decreased, while that from seddling emergence to harvesting increased, consequently, the yield increased by 11.6…14.7%. The maximum yield was obtained with the Red Scarlet variety using the white covering material, the minimum – in the check variant without covering. The same trend is typical for other varieties. It has been established that covering with any material has a positive eff ect on the duration of the potato growing season and the yield by increasing the period of tuberization. Covering allows getting early potato varieties 2 weeks earlier in the Moscow region.

Rice (Oryza sativa L.) germplasm with better seedling emergence under direct sowing in flooded paddy field

2018 ◽  
Vol 16 (4) ◽  
pp. 352-358 ◽  
Author(s):  
Junichi Kashiwagi ◽  
Koji Hamada ◽  
Yutaka Jitsuyama
Keyword(s):  
Paddy Field ◽  
Oryza Sativa L ◽  
Seedling Emergence ◽  
Screening Method ◽  
Paddy Fields ◽  
Rice Germplasm ◽  
Geographical Regions ◽  
Wide Range ◽  
Cultivation Practice ◽  
Direct Sowing

AbstractDirect sowing of rice in a flooded paddy field is a beneficial cultivation practice for water use and labour efficiency, compared to the transplanted cultivation. However, a drastic reduction in seedling emergence under flooded paddy fields is a serious constraint especially when the seeds fell at deeper soil layers. Suitable rice germplasm for the direct sowing in flooded paddy fields could ensure the success of this cultivation practice. Instead of laborious field-based screening systems, a pot-based screening method was adopted for simplicity and efficient evaluation of seedling emergence of a subset of world rice germplasm (n = 75) at different sowing depths. As a result, two rice genotypes, ‘Vary Futsi’ (landrace from Madagascar, non-glutinous, subspecies Indica) and ‘Dahonggu’ (landrace from China, non-glutinous, subspecies Indica), with consistently better seedling emergence were identified from a wide range of rice germplasm. These genotypes could serve as excellent parents for the breeding program in developing new rice cultivars with the improved seedling emergence in flooded paddy fields. There were no significant differences in the seedling emergence rate in flooded paddy conditions among the groups from various agro-geographical regions.

scholarly journals Seed Germination Variation among Crop Years from a Pinus sylvestris Clonal Seed Orchard

2019 ◽  
pp. 1-14
Author(s):  
Melusi Rampart
Keyword(s):  
Seed Germination ◽  
Seed Weight ◽  
Seed Orchard ◽  
Climatic Conditions ◽  
Thermal Time ◽  
Base Temperature ◽  
Germination Capacity ◽  
Seed Collection ◽  
Clonal Seed Orchard ◽  
The Mean

Maternal effects were assessed by germinating seeds sourced over multiple years from the same cloned mother trees, comparing germination capacity and rate between crop years. The relationships between climatic variables, seed characteristics and germination capacity were determined, and thermal time parameters were used to predict seed dormancy release and germination under the climatic conditions in the year after seed collection. There were significant differences in seed weight (P < 0.05), seed length and embryo occupancy (both P < 0.001) among crop years. Temperature during the seed development period explained 70% of the variation in seed weight and 63% of the variation in embryo occupancy. Germination capacity was significantly (P <0.001) different among crop years, among temperatures and among chilling durations, and thermal time requirements for germination increased from older (2007) to younger (2012) seeds. The mean base temperature without chilling was 7.1°C, while after chilling it was 4.6°C and 3.6°C for four and eight weeks chilling respectively. The mean thermal time to 50% germination without chilling was 135.1°Cd, while after chilling it was 118.3°Cd and 154.0°Cd for four and eight weeks chilling respectively. This experiment demonstrates that year-to-year differences in the environment experienced by mother trees during seed maturation can affect seed germination characteristics.

scholarly journals Temperatura-base e soma térmica para a Zínia ‘Profusion Cherry’ envasada cultivada em ambiente protegido

2016 ◽  
Vol 21 (3) ◽  
pp. 376
Author(s):  
Charleston Gonçalves ◽  
Carlos Eduardo Ferreira Castro ◽  
Mário José Pedro Júnior ◽  
Maria Luiza Sant’anna Tucci
Keyword(s):  
New Species ◽  
Thermal Time ◽  
Base Temperature ◽  
Degree Days ◽  
Consumer Market ◽  
Open Flower ◽  
Lack Of Information ◽  
Protected Cultivation

The growing of consumer market demands introduction of new species of flowers and cultivars primarily for production under protected cultivation. The zinnia by the quickness of production can be regarded as an alternative, however demand studies by the lack of information in the literature. We evaluated the duration of different periods, the base temperature and thermal accumulation, expressed as degree-days for the potted zinnia ‘Profusion Cherry’, conducted under protected cultivation for different phenological subperiods. The test was conducted in a greenhouse covered with plastic and closed laterally with shading-net and the duration of subperiods were made to twenty times after sowing. The base temperature was determined by relative development and values-based temperature and thermal time in degree-days (DD). The results for the different phases were, respectively: first open flower-planting: 4.1 °C and GD 838, first open flower - 50% of flowers open: 3.0 °C and 184 GD and 50% of flowers open - senescence: 6.9 °C and 238 GD.

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