scholarly journals Screening for Cold Tolerance during Germination within Sweet and Fiber Sorghums [Sorghum bicolor (L.) Moench] for Energy Biomass

Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 620
Author(s):  
Cristina Patanè ◽  
Salvatore L. Cosentino ◽  
Valeria Cavallaro ◽  
Alessandro Saita
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Cold Tolerance ◽  
Fiber Type ◽  
Warm Season ◽  
Early Spring ◽  
Thermal Time ◽  
Base Temperature ◽  
Biomass Sorghum ◽  
Germination Response

Within the project “BIOSEA” funded by the Italian Ministry of Agriculture and Forestry, a preliminary laboratory test was conducted to assess the variability for cold tolerance during germination in 30 cultivars of biomass sorghum, among fiber and sweet types. Seed germination (%) and mean germination time (MGT) were examined at seven constant temperatures (from 8 °C to 35 °C) and base temperature (Tb) and thermal time (θT) for 50% germination were calculated. A wide genetic diversity in the germination response of sorghum was ascertained at 8 °C (CV 45%) and 10 °C (CV 25.4%). At 8 °C, in cultivars of ‘Padana 4’, ‘PR811F’, ‘PSE24213’, ‘PR849’ and ‘Zerberus’, seed germination exceeded 80%. Seeds of ‘Zerberus’ were also the fastest, requiring less than 13 days for final germination at this low temperature. Great differences were found in Tb and θT among cultivars. Tb varied between 7.44 °C (‘PR811F’) and 13.48 °C (‘Nectar’). Thermal time (θT) was, on average, 24.09 °Cd−1, and ranged between 16.62 (‘Nectar’) and 33.42 °Cd−1 (‘PSE24213’). The best combination of the two germination parameters (i.e., low Tb and θT) corresponded to ‘Zerberus’, ‘Sucrosorgo 506’, ‘Jumbo’ and ‘PR811F’. Accordingly, these cultivars are more tolerant to cold stress during germination and, thus, more adapt to early spring sowings in Mediterranean areas (March-April). Cultivars ‘PR811F’ (fiber type) and ‘Sucrosorgo 506’ (sweet type) also combine high cold tolerance with good productivity in terms of final dry biomass, as assessed in open-field conditions (late spring sowing). The genetic variation in the germination response to a low temperature is useful for the identification of genotypes of sorghum suitable to early sowings in semi-arid areas. Selection within existing cultivars for cold tolerance during germination may also contribute to the expansion of biomass sorghum into cooler cultivation areas, such as those of Northern Europe, which are less suitable to this warm season crop.

scholarly journals Application of the thermal time model for different Typha domingensis populations

2020 ◽  
Author(s):  
Fanny Mabel Carhuancho León ◽  
Pedro Luis Aguado Cortijo ◽  
María del Carmen Morató Izquierdo ◽  
María Teresa Castellanos Moncho
Keyword(s):  
Seed Germination ◽  
Mean Value ◽  
Thermal Time ◽  
Plant Responses ◽  
Base Temperature ◽  
Typha Domingensis ◽  
Time Model ◽  
Germination Response ◽  
Thermal Regimes ◽  
Thermal Time Model

Abstract Background: Cattail (Typha domingensis Pers.) is a perennial emergent plant which is used in Green Floating Filters (GFFs), one of the most innovative systems of wastewater treatment to bioremediate eutrophic waters and produce biomass as biofuel feedstocks. The establishment of cattails in GFFs depends on the seed germination and plant responses under conditions of a new habitat. This study analysed the germination responses of four different populations of cattails through a thermal time model to know their basic parameters of germination and which population would be more adapted to the conditions tested.Results: Seeds from the Badajoz (Ba), Cuenca (Cu), Madrid (Ma), Seville (Se) and Toledo (To) populations were exposed to different thermal regimes (constant, and alternating temperatures between 15 and 30°C) and different darkness treatments (between 0 and 20 days with 24h dark photoperiod, then exposed to light with 12h light/dark photoperiod) to determine the parameters of the thermal model from germination levels in each treatment. To population was used to validate the thermal time parameters of other populations. Regardless of the other parameters, no germination occurred in total darkness. The mean value of base temperature (Tb) was 16.4±0.2°C in all treatments. Optimum temperature (To) values in Ma and Ba were 25°C, and those in Cu and Se were 22.5°C. The germination response decreased when the temperature approached Tb and increased when it was close to To. In comparison to alternating temperatures, constant temperatures had the highest germination response and lowest thermal time (θT(50)). Darkness treatments had a direct relationship with θT(50). The population origin also affected seed germination; Cu had the highest values of To and germination response but had a lower θT(50), which coincides with the lowest mean ambient temperatures. Conclusion : According to these results, the germination response of cattails was high in all populations under optimal conditions but was affected to a greater or lesser extent depending on thermal regimes, darkness treatments, and populations. The thermal time model allowed us to determine that To was between 22.5-25ºC and that Cu is the best population regarding the germination response under the conditions tested.

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 Application of the thermal time model for different Typha domingensis populations

2020 ◽  
Author(s):  
Fanny Mabel Carhuancho León ◽  
Pedro Luis Aguado Cortijo ◽  
María del Carmen Morató Izquierdo ◽  
María Teresa Castellanos Moncho
Keyword(s):  
Seed Germination ◽  
Mean Value ◽  
Thermal Time ◽  
Plant Responses ◽  
Base Temperature ◽  
Typha Domingensis ◽  
Time Model ◽  
Germination Response ◽  
Thermal Regimes ◽  
Thermal Time Model

Abstract BackgroundCattail (Typha domingensis Pers.) is a perennial emergent plant which is used in Green Floating Filters (GFFs), one of the most innovative systems of wastewater treatment to bioremediate eutrophic waters and produce biomass as biofuel feedstocks. The establishment of cattails in GFFs depends on the seed germination and plant responses under conditions of a new habitat. This study analysed the germination response of four different populations of cattails through a thermal time model to determine which population would have the fastest germination for establishment in GFFs.ResultsSeeds from the Badajoz (Ba), Cuenca (Cu), Madrid (Ma), Seville (Se) and Toledo (To) populations were exposed to different thermal regimes (constant, and alternating temperatures between 15 and 30°C) and differents darkness treatments (between 0 and 20 days with 24h dark photoperiod, then exposed to light with 12h light/dark photoperiod) to determine the parameters of the thermal model from germination levels in each treatment. To population was used to validate the thermal time parameters of other populations. Regardless of the other parameters, no germination occurred in total darkness. The mean value of base temperature (Tb) was 16.4±0.2°C in all treatments. Optimum temperature (To) values in Ma and Ba were 25°C, and those in Cu and Se were 22.5°C. The germination response decreased when the temperature approached Tb and increased when it was close to To. In comparison to alternating temperatures, constant temperatures had the highest germination response and lowest thermal time (θT(50)). Darkness treatments had a direct relationship with θT(50). The population origin also affected seed germination; Cu had the highest values of To and germination response but had a lower θT(50), which coincides with the lowest mean ambient temperatures.Conclusion According to these results, the germination response of cattails was high in all populations under optimal conditions but was affected to a greater or lesser extent depending on thermal regimes, darkness treatments, and populations. The thermal time model allowed us to determine that To was between 22.5-25ºC. In comparison to other populations, Cu is the best population for establishment in GFFs due to its high germination response under the conditions tested.

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 Opportunistic Germination Behaviour of Gypsophila (Caryophyllaceae) in Two Priority Habitats from Semi-arid Mediterranean Steppes

2011 ◽  
Vol 39 (1) ◽  
pp. 18 ◽  
Author(s):  
Felix MORUNO ◽  
Pilar SORIANO ◽  
Oscar VICENTE ◽  
Monica BOSCAIU ◽  
Elena ESTRELLES
Keyword(s):  
Seed Germination ◽  
Climatic Conditions ◽  
Thermal Time ◽  
Distribution Area ◽  
Base Temperature ◽  
Additional Information ◽  
High Viability ◽  
Germination Behaviour ◽  
Alternating Temperature

Gypsophila tomentosa and G. struthium are closely related species, characteristic of two European priority habitats, salt and gypsum inland steppes, respectively. Germination strategies of the two taxa were investigated in plants from two nearby populations, growing under the same climatic conditions but on different types of soil, and belonging to different plant communities. Their germination patterns were studied at five constant temperatures in darkness: 5oC, 10oC, 15oC, 20oC and 25oC, and the base temperature and the thermal time requirement were calculated. As the distribution area of both species is subjected to a Mediterranean continental climate with significant differences between day and night, the possible preferences for an alternating temperature regime (25/10oC) were contrasted, as well as the influence of cold stratification and freezing. The effects on seed germination of light at constant 20oC and a 12/12 h photoperiod were also compared in the two species. The main conclusions of the work are the similarity of behaviour of both species, with an absence of seed dormancy, their opportunistic germination strategy, and water availability as the principal limitation to seed germination and plant establishment. The base temperature and thermal time indicate higher competitiveness of G. struthium at low temperatures, but seed germination of G. tomentosa is the most efficient at temperatures higher than 13.3oC. Optimal temperature and illumination conditions for nursery propagation depend on the species. The high viability of seeds observed after freezing prove the orthodox character of these seeds, providing additional information for long term seed conservation procedures.

scholarly journals Association mapping of germinability and seedling vigor in sorghum under controlled low-temperature conditions

Genome ◽  
2016 ◽  
Vol 59 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Hari D. Upadhyaya ◽  
Yi-Hong Wang ◽  
Dintyala V.S.S.R. Sastry ◽  
Sangam L. Dwivedi ◽  
P.V. Vara Prasad ◽  
...  
Keyword(s):  
Seed Germination ◽  
Low Temperature ◽  
Cold Tolerance ◽  
Germination Rate ◽  
Strong Association ◽  
Marker Locus ◽  
Seedling Vigor ◽  
Mini Core Collection ◽  
Genome Wide ◽  
Soil Temperatures

Sorghum is one of the world’s most important food, feed, and fiber crops as well as a potential feedstock for lignocellulosic bioenergy. Early-season planting extends sorghum’s growing season and increases yield in temperate regions. However, sorghum’s sensitivity to low soil temperatures adversely impacts seed germination. In this study, we evaluated the 242 accessions of the ICRISAT sorghum mini core collection for seed germination and seedling vigor at 12 °C as a measure of cold tolerance. Genome-wide association analysis was performed with approximately 162 177 single nucleotide polymorphism markers. Only one marker locus (Locus 7-2) was significantly associated with low-temperature germination and none with vigor. The linkage of Locus 7-2 to low-temperature germination was supported by four lines of evidence: strong association in three independent experiments, co-localization with previously mapped cold tolerance quantitative trait loci (QTL) in sorghum, a candidate gene that increases cold tolerance and germination rate when its wheat homolog is overexpressed in tobacco, and its syntenic region in rice co-localized with two cold tolerance QTL in rice. This locus may be useful in developing tools for molecular breeding of sorghums with improved low-temperature germinability.

DISTINGUISHING THE EFFECTS OF GENOTYPE AND SEED PHYSIOLOGICAL AGE ON LOW TEMPERATURE TOLERANCE OF RICE (ORYZA SATIVA L.)

2006 ◽  
Vol 42 (3) ◽  
pp. 337-349 ◽  
Author(s):  
M. G. ALI ◽  
R. E. L. NAYLOR ◽  
S. MATTHEWS
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Oryza Sativa L ◽  
Ageing Time ◽  
Physiological State ◽  
Thermal Time ◽  
Physiological Age ◽  
Base Temperature ◽  
Seed Moisture Content ◽  
Rice Genotypes

When differences are observed between genotypes in their response to low temperatures at germination, it has been generally assumed these are purely genetic. Laboratory experiments were carried out to evaluate the effects of physiological age on the temperature responses of 13 rice genotypes from Bangladesh in order to clarify whether (a) differences in seed germination at low temperature represented genetic differences or differences in the physiological state of the particular seed lot used and (b) whether genotype performance at higher temperatures was indicative of performance at lower temperatures. A higher initial seed moisture content (mc) was associated with lower initial viability (Ki). The base temperature for germination differed by less than 1 °C between genotypes. Seeds remaining ungerminated at low temperatures usually germinated when transferred to 21 °C. The thermal time requirement to reach t50 (θ) differed widely between genotypes. Lower optimum temperatures for germination were associated with lower thermal time requirements. Ageing seeds for 24 hours at 24 % mc and 45 °C significantly reduced final germination on a thermal gradient table at all temperatures below 20.8 °C in genotype BR29 but only below 16.5 °C in BR11. The rates of germination (seeds d−1) of aged seeds were also lower at all temperatures. Germination of high quality seeds of four genotypes were compared at 21 °C and 11 °C both before and after ageing (at 24 % mc and 45 °C). Ageing consistently reduced the rates of germination at both 21 °C and 11 °C. Increased ageing time progressively reduced the rate of germination of all seed lots at both temperatures. The rates of germination at 11 °C and 21 °C were positively and significantly (p < 0.01) related to final germination at the lower temperature of 11 °C. These results demonstrate that seed physiological quality as well as genotype might influence the final germination and rate of germination of rice genotypes at low temperatures. This information will be useful for breeders involved in selection of lines suitable for growing in cooler seasons.

Temperature- and moisture-dependent models of seed germination and shoot elongation in green and redroot pigweed (Amaranthus powellii, A. retroflexus)

Weed Science ◽  
1997 ◽  
Vol 45 (4) ◽  
pp. 488-496 ◽  
Author(s):  
Joseph O. E. Oryokot ◽  
Stephen D. Murphy ◽  
A. Gordon Thomas ◽  
Clarence J. Swanton
Keyword(s):  
Seed Germination ◽  
Water Potential ◽  
Weed Management ◽  
Germination Rate ◽  
Shoot Elongation ◽  
Thermal Time ◽  
Base Temperature ◽  
Mathematical Function ◽  
Redroot Pigweed ◽  
Mean Temperature

To predict weed emergence and help farmers make weed management decisions, we constructed a mathematical model of seed germination for green and redroot pigweed based on temperature and water potential (moisture) and expressing cumulative germination in terms of thermal time (degree days). Empirical observations indicated green pigweed germinated at a lower base temperature than redroot pigweed but the germination rate of redroot pigweed is much faster as mean temperature increases. Moisture limitation delayed seed germination until 23.8 C (green pigweed) or 27.9 (redroot pigweed); thereafter, germination was independent of water potential as mean temperatures approached germination optima. Our germination model, based on a cumulative normal distribution function, accounted for 80 to 95% of the variation in seed germination and accurately predicted that redroot pigweed would have a faster germination rate than green pigweed. However, the model predicted that redroot pigweed would germinate before green pigweed (in thermal time) and was generally less accurate during the early period of seed germination. The model also predicted that moisture limitation would increase, rather than delay, seed germination. These errors were related to the mathematical function chosen and analyses used, but an explicit interaction term for water potential and temperature is also needed to produce an accurate model. We also tested the effect of mean temperature on shoot elongation (emergence) and described the relationship by a linear model. Base temperatures for shoot elongation were higher than for seed germination. Shoot elongation began at 15.6 and 14.4 C for green and redroot pigweed, respectively; they increased linearly with temperature until the optimum of 27.9 C was reached. Elongation was dependent on completion of the rate-limiting step of radicle emergence and was sensitive to temperature but not moisture; hence, elongation was sensitive to a much smaller temperature range. Beyond mathematical changes, we are testing our model in the field and need to link it to ecophysiological, genetic, and spatially explicit population processes for it to be useful in decision support for weed management.

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