The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Daniel J. Miralles - One of the best experts on this subject based on the ideXlab platform.
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Variability in the Duration of Stem Elongation in Wheat and Barley Genotypes
Journal of Agronomy and Crop Science, 2007Co-Authors: E. M. Whitechurch, Gustavo A. Slafer, Daniel J. MirallesAbstract:The Stem Elongation phase in wheat (Triticum aestivum, L.) and barley (Hordeum vulgare) is important for yield determination as it is the phase when Stems and spikes grow actively. A longer duration of this phase could hypothetically increase assimilate availability, fertile florets at anthesis and final grain number. Argentine commercial wheat and barley cultivars were studied to analyse the range of genetic variability existing in the duration of the Stem Elongation phase, in particular, considering cultivars with similar time to anthesis. It was found that cultivars differing in time to anthesis, not only differed in the length of their early, mostly vegetative phases but also in the Stem Elongation phase (range 301-535 °C day for wheat and 252-404 °C day for barley), and that the partitioning of a similar time to anthesis into phases was substantially different between cultivars. Various studies with other cultivars were re-analysed, showing that the Stem Elongation phase did present genetic variability as well. As a preliminary step to identifying the genetic causes behind this variability, an approximation to the possible photoperiod and/or vernalization sensitivities of this large group of Argentine cultivars was presented, by comparing behaviour in two contrasting sowing dates. This has proved useful to breeders since there have been no other previous studies including this large number of commercial cultivars.
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Variability in the Duration of Stem Elongation in Wheat Genotypes and Sensitivity to Photoperiod and Vernalization
Journal of Agronomy and Crop Science, 2007Co-Authors: E. M. Whitechurch, Gustavo A. Slafer, Daniel J. MirallesAbstract:The Stem Elongation phase in wheat [Triticum aestivum (L.)] is considered critical for yield determination. A longer duration of this phase could hypothetically increase grain set and therefore yield. Genetic variation in the relative duration of the Stem Elongation phase having been reported, the aim was to pinpoint whether this variability was associated with sensitivity to photoperiod, vernalizing temperatures or to differences in intrinsic earliness. Pairs of cultivars identified as having different duration of the Stem Elongation phase (from the appearance of the first visible node to anthesis) were grown under natural (short) or extended photoperiod, with or without vernalization. Variability in the duration of this phase, in the cultivars analysed, was related to different sensitivity to photoperiod, while differences in the previous phases were related to sensitivity to both photoperiod (though different to the sensitivity of the following phase) and vernalization.
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floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during Stem Elongation
Functional Plant Biology, 2005Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Wheat breeding has improved yield potential increasing floret survival through higher dry matter partitioning to the spikes during the Stem Elongation phase (from terminal spikelet initiation to anthesis). We studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments applied during the Stem Elongation phase. The cultivar Buck Manantial was exposed to (1) NP+0 un-shaded (natural photoperiod and incoming radiation of the growing season), (2) NP+0 shaded (natural photoperiod but only 33% of the incoming radiation), and (3) NP+6 un-shaded (natural photoperiod extended 6 h and natural incoming radiation). Floret survival increased, depending on spikelet position, 1.1–2.5 fold under un-shaded v. shaded treatments (both under NP+0), and 1.3–1.8 fold under NP+0 v. NP+6 treatments (both un-shaded), without any impact of treatments on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were associated with duration of floret development within the Stem Elongation phase (R2 = 82%, P<0.0001). Florets may be classified into three groups: (i) those that were fertile at anthesis under all treatments (mostly the two florets F1 and F2, proximal to the rachis within the spikelet), (ii) those that reached different stages at anthesis, depending on treatment, and that contributed differentially to the number of fertile florets at anthesis (mostly the florets F3, F4 and F5, positioned in the middle of the spikelet), and (iii) those that did not contribute to the number of fertile florets under any treatment (mostly the florets ≥ F6). Degeneration of florets in group (ii) was associated with spike growth at maximum rate, explaining the strong relationship observed between spike dry weight at anthesis and number of fertile florets. However, degeneration of florets in group (iii) seemed to occur before spike growth at maximum rate. Survival of florets positioned in the middle of the spikelets could be improved by increasing spike growth through manipulation of photoperiod sensitivity during Stem Elongation.
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Floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during Stem Elongation
Functional plant biology : FPB, 2005Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Wheat breeding has improved yield potential increasing floret survival through higher dry matter partitioning to the spikes during the Stem Elongation phase (from terminal spikelet initiation to anthesis). We studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments applied during the Stem Elongation phase. The cultivar Buck Manantial was exposed to (1) NP+0 un-shaded (natural photoperiod and incoming radiation of the growing season), (2) NP+0 shaded (natural photoperiod but only 33% of the incoming radiation), and (3) NP+6 un-shaded (natural photoperiod extended 6 h and natural incoming radiation). Floret survival increased, depending on spikelet position, 1.1–2.5 fold under un-shaded v. shaded treatments (both under NP+0), and 1.3–1.8 fold under NP+0 v. NP+6 treatments (both un-shaded), without any impact of treatments on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were associated with duration of floret development within the Stem Elongation phase (R2 = 82%, P
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Floret development and spike growth as affected by photoperiod during Stem Elongation in wheat
Field Crops Research, 2003Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Abstract A longer duration of Stem Elongation (from terminal spikelet initiation to anthesis) would result in a higher wheat yield potential as a consequence of the increase in both spike dry weight and number of fertile florets at anthesis. It is not clearly understood, however, which processes are involved in the increased spike dry weight and whether this variable accounts for the higher number of fertile florets when duration of Stem Elongation is modified by photoperiod treatments. As vernalization interacts with photoperiod during the Stem Elongation phase, a better understanding of the role of vernalization is also required. A field experiment was carried out using two wheat cultivars (Buck Manantial (BM) and Eureka Ferrocarril Sur (EFS)) subjected to diverse periods of vernalization (V 15 and V 50 , plants vernalized for 15 and 50 days, respectively) and exposed to different photoperiods (NP+0 and NP+6, natural and 6 h extended photoperiod, respectively) only during the Stem Elongation phase. Floret development together with Stem and spike growth during the Stem Elongation phase were studied. When the Stem Elongation phase was exposed to short photoperiod (i) duration of spike growth increased without any change in its growth rate, and (ii) most of the spike growth occurred during minimum Stem growth rate as the onset of maximum Stem growth rate was delayed. In EFS, the vernalization-sensitive cultivar, the former (i) and (ii) was true only when vernalization requirements were met. For both cultivars, the survival of the initiated floret primordia under short photoperiod increased, independently of vernalization. Both partitioning of assimilates to the spike and a direct photoperiod effect seemed to have been involved in the survival of floret primordia when the Stem Elongation phase was exposed to short photoperiod.
Gustavo A. Slafer - One of the best experts on this subject based on the ideXlab platform.
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Variability in the Duration of Stem Elongation in Wheat and Barley Genotypes
Journal of Agronomy and Crop Science, 2007Co-Authors: E. M. Whitechurch, Gustavo A. Slafer, Daniel J. MirallesAbstract:The Stem Elongation phase in wheat (Triticum aestivum, L.) and barley (Hordeum vulgare) is important for yield determination as it is the phase when Stems and spikes grow actively. A longer duration of this phase could hypothetically increase assimilate availability, fertile florets at anthesis and final grain number. Argentine commercial wheat and barley cultivars were studied to analyse the range of genetic variability existing in the duration of the Stem Elongation phase, in particular, considering cultivars with similar time to anthesis. It was found that cultivars differing in time to anthesis, not only differed in the length of their early, mostly vegetative phases but also in the Stem Elongation phase (range 301-535 °C day for wheat and 252-404 °C day for barley), and that the partitioning of a similar time to anthesis into phases was substantially different between cultivars. Various studies with other cultivars were re-analysed, showing that the Stem Elongation phase did present genetic variability as well. As a preliminary step to identifying the genetic causes behind this variability, an approximation to the possible photoperiod and/or vernalization sensitivities of this large group of Argentine cultivars was presented, by comparing behaviour in two contrasting sowing dates. This has proved useful to breeders since there have been no other previous studies including this large number of commercial cultivars.
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Variability in the Duration of Stem Elongation in Wheat Genotypes and Sensitivity to Photoperiod and Vernalization
Journal of Agronomy and Crop Science, 2007Co-Authors: E. M. Whitechurch, Gustavo A. Slafer, Daniel J. MirallesAbstract:The Stem Elongation phase in wheat [Triticum aestivum (L.)] is considered critical for yield determination. A longer duration of this phase could hypothetically increase grain set and therefore yield. Genetic variation in the relative duration of the Stem Elongation phase having been reported, the aim was to pinpoint whether this variability was associated with sensitivity to photoperiod, vernalizing temperatures or to differences in intrinsic earliness. Pairs of cultivars identified as having different duration of the Stem Elongation phase (from the appearance of the first visible node to anthesis) were grown under natural (short) or extended photoperiod, with or without vernalization. Variability in the duration of this phase, in the cultivars analysed, was related to different sensitivity to photoperiod, while differences in the previous phases were related to sensitivity to both photoperiod (though different to the sensitivity of the following phase) and vernalization.
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floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during Stem Elongation
Functional Plant Biology, 2005Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Wheat breeding has improved yield potential increasing floret survival through higher dry matter partitioning to the spikes during the Stem Elongation phase (from terminal spikelet initiation to anthesis). We studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments applied during the Stem Elongation phase. The cultivar Buck Manantial was exposed to (1) NP+0 un-shaded (natural photoperiod and incoming radiation of the growing season), (2) NP+0 shaded (natural photoperiod but only 33% of the incoming radiation), and (3) NP+6 un-shaded (natural photoperiod extended 6 h and natural incoming radiation). Floret survival increased, depending on spikelet position, 1.1–2.5 fold under un-shaded v. shaded treatments (both under NP+0), and 1.3–1.8 fold under NP+0 v. NP+6 treatments (both un-shaded), without any impact of treatments on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were associated with duration of floret development within the Stem Elongation phase (R2 = 82%, P<0.0001). Florets may be classified into three groups: (i) those that were fertile at anthesis under all treatments (mostly the two florets F1 and F2, proximal to the rachis within the spikelet), (ii) those that reached different stages at anthesis, depending on treatment, and that contributed differentially to the number of fertile florets at anthesis (mostly the florets F3, F4 and F5, positioned in the middle of the spikelet), and (iii) those that did not contribute to the number of fertile florets under any treatment (mostly the florets ≥ F6). Degeneration of florets in group (ii) was associated with spike growth at maximum rate, explaining the strong relationship observed between spike dry weight at anthesis and number of fertile florets. However, degeneration of florets in group (iii) seemed to occur before spike growth at maximum rate. Survival of florets positioned in the middle of the spikelets could be improved by increasing spike growth through manipulation of photoperiod sensitivity during Stem Elongation.
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Floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during Stem Elongation
Functional plant biology : FPB, 2005Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Wheat breeding has improved yield potential increasing floret survival through higher dry matter partitioning to the spikes during the Stem Elongation phase (from terminal spikelet initiation to anthesis). We studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments applied during the Stem Elongation phase. The cultivar Buck Manantial was exposed to (1) NP+0 un-shaded (natural photoperiod and incoming radiation of the growing season), (2) NP+0 shaded (natural photoperiod but only 33% of the incoming radiation), and (3) NP+6 un-shaded (natural photoperiod extended 6 h and natural incoming radiation). Floret survival increased, depending on spikelet position, 1.1–2.5 fold under un-shaded v. shaded treatments (both under NP+0), and 1.3–1.8 fold under NP+0 v. NP+6 treatments (both un-shaded), without any impact of treatments on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were associated with duration of floret development within the Stem Elongation phase (R2 = 82%, P
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Floret development and spike growth as affected by photoperiod during Stem Elongation in wheat
Field Crops Research, 2003Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Abstract A longer duration of Stem Elongation (from terminal spikelet initiation to anthesis) would result in a higher wheat yield potential as a consequence of the increase in both spike dry weight and number of fertile florets at anthesis. It is not clearly understood, however, which processes are involved in the increased spike dry weight and whether this variable accounts for the higher number of fertile florets when duration of Stem Elongation is modified by photoperiod treatments. As vernalization interacts with photoperiod during the Stem Elongation phase, a better understanding of the role of vernalization is also required. A field experiment was carried out using two wheat cultivars (Buck Manantial (BM) and Eureka Ferrocarril Sur (EFS)) subjected to diverse periods of vernalization (V 15 and V 50 , plants vernalized for 15 and 50 days, respectively) and exposed to different photoperiods (NP+0 and NP+6, natural and 6 h extended photoperiod, respectively) only during the Stem Elongation phase. Floret development together with Stem and spike growth during the Stem Elongation phase were studied. When the Stem Elongation phase was exposed to short photoperiod (i) duration of spike growth increased without any change in its growth rate, and (ii) most of the spike growth occurred during minimum Stem growth rate as the onset of maximum Stem growth rate was delayed. In EFS, the vernalization-sensitive cultivar, the former (i) and (ii) was true only when vernalization requirements were met. For both cultivars, the survival of the initiated floret primordia under short photoperiod increased, independently of vernalization. Both partitioning of assimilates to the spike and a direct photoperiod effect seemed to have been involved in the survival of floret primordia when the Stem Elongation phase was exposed to short photoperiod.
David M Reid - One of the best experts on this subject based on the ideXlab platform.
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red far red light mediated Stem Elongation and anthocyanin accumulation in stellaria longipes differential response of alpine and prairie ecotypes
Botany, 2002Co-Authors: Suneetha Alokam, C C Chinnappa, David M ReidAbstract:We compared the Stem Elongation response and anthocyanin accumulation between alpine and prairie plants of Stellaria longipes Goldie under different red/far-red light ratios (R/FR) of 0.7 and 1.9 while all other environmental conditions were uniform. Both ecotypes responded to light quality. The prairie ecotype, considered to be the shade avoider, showed greater Stem Elongation in response to low R/FR (0.7) than under high R/FR (1.9) as compared with the alpine ecotype. The levels of anthocyanin in prairie plants, as compared with alpine plants, were significantly higher under high R/FR. Under low R/FR, both showed almost the same levels of anthocyanin. Also, the two ecotypes upon etiolation showed differences in the sites of anthocyanin accumulation under different R/FR. The results of the present study show that the extent of the Stem Elongation response and anthocyanin accumulation in the two ecotypes of S. longipes is likely a result of their origins in two contrasting habitats.Key words: Stellaria, p...
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Red/far-red light mediated Stem Elongation and anthocyanin accumulation in Stellaria longipes: differential response of alpine and prairie ecotypes
Canadian Journal of Botany, 2002Co-Authors: Suneetha Alokam, C. C. Chinnappa, David M ReidAbstract:We compared the Stem Elongation response and anthocyanin accumulation between alpine and prairie plants of Stellaria longipes Goldie under different red/far-red light ratios (R/FR) of 0.7 and 1.9 while all other environmental conditions were uniform. Both ecotypes responded to light quality. The prairie ecotype, considered to be the shade avoider, showed greater Stem Elongation in response to low R/FR (0.7) than under high R/FR (1.9) as compared with the alpine ecotype. The levels of anthocyanin in prairie plants, as compared with alpine plants, were significantly higher under high R/FR. Under low R/FR, both showed almost the same levels of anthocyanin. Also, the two ecotypes upon etiolation showed differences in the sites of anthocyanin accumulation under different R/FR. The results of the present study show that the extent of the Stem Elongation response and anthocyanin accumulation in the two ecotypes of S. longipes is likely a result of their origins in two contrasting habitats.Key words: Stellaria, p...
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Stem Elongation and gibberellins in alpine and prairie ecotypes of Stellaria longipes
Plant Growth Regulation, 2001Co-Authors: R.j.n. Emery, David M Reid, Richard P. Pharis, David W. Pearce, C. C. ChinnappaAbstract:The potential for gibberellins (GAs) to control Stem Elongation and itsplasticity (range of phenotypic expression) was investigated inStellaria longipes grown in long warm days. Gibberellinmetabolism and sensitivity was compared between a slow-growing alpine dwarfwithlow Stem Elongation plasticity and a rapidly elongating, highly plastic prairieecotype. Both ecotypes elongated in response to exogenous GA1,GA4 or GA9, but surprisingly, the alpine dwarf wasrelatively unresponsive to GA3. Endogenous GA1,GA3, GA4, GA5, GA8, GA9and GA20 were identified and quantified in Stem tissue harvested atcommencement, middle and end of the period of most rapid Elongation. Theconcentration of GAs which might be expected to promote shoot Elongation washigher during rapid Elongation than toward its end for both ecotypes. Whilethere was a trend for certain GAs (GA3, GA4,GA9, GA20) to be higher in Stems of the alpine ecotypeduring rapid Elongation, that result does not explain the slower growth of thealpine ecotype and the faster growth of the prairie ecotype under a range ofconditions. To determine if the two ecotypes metabolized GA20differently, plants were fed [2H]- or[3H]-GA20. The metabolic products identified included[2H2]-GA1, -GA8, -GA29,-GA60, -3-epi-GA1, GA118(-1-epi-GA60) and -GA77. The concentration of[2H2]-GA1 also did not differ between the twoecotypes and metabolism of [2H2]- or[3H]-GA20 was also similar. In the same experiments thepresence of epi-GA1, GA29, GA60,GA118 and GA77 was indicated, suggesting that these GAsmay also occur naturally in S. longipes, in addition tothose described above. Collectively, these results suggest that while StemElongation within ecotypes is likely regulated by GAs, differences in GAcontent, sensitivity to GAs (GA3 excepted), or GA metabolism areunlikely to be the controlling factor in determining the differences seen ingrowth rate between the two ecotypes under the controlled environmentconditionsof this study. Nevertheless, further study is warranted especially underconditions where environmental factors may favour a GA:ethylene interaction.
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Effect of light quality and 5-azacytidine on genomic methylation and Stem Elongation in two ecotypes of Stellaria longipes
Physiologia Plantarum, 2000Co-Authors: Gurminder S. Tatra, C C Chinnappa, Jacintha Miranda, David M ReidAbstract:Changes in cytosine methylation are known to occur in response to various environmental stimuli, therefore, we looked at methylation changes in relation to Stem Elongation. More specifically, we investigated the response of genomic cytosine methylation to irradiance-mediated plasticity of Stem Elongation in two ecotypes of Stellaria longipes. Ramets of S. longipes were grown under high and low ratios of red/far-red light (F/FR; 3.7 and 0.7, respectively). Stem Elongation and methylated cytosine content were measured over a period of 7 days. Ramets of S. longipes demonstrated the highest level of demethylation after 4 days of long-day warm (LDW) treatment, which coincides with the first day of rapid Stem Elongation initiation. The extent of demethylation associated with day 4 depended upon the relative ratio of R/FR light. In particular, those plants treated with low R/FR light ratios showed a lower level of methylation, and were taller than the high R/FR light grown counterparts. In addition, prairie ecotype plants demonstrated lower day 4 methylation levels, as well as longer day 7 Stem lengths, than the alpine ecotype plants within the same R/FR light treatments. To investigate if the degree of methylation was a crucial factor in controlling the Stem Elongation response, ramets of both alpine and prairie plants were grown in MS media supplemented with 5-azacytidine (5-AzaC), and grown for 14 days under a R/FR ratio of 3.7 and two different PAR values. 5-AzaC treatments demonstrated that the prairie ecotype plants required greater doses of 5-AzaC, and thus lower methylation levels, than the alpine ecotype plants in order to promote maximal Stem Elongation. These observations suggest that DNA demethylation is involved in the shade-avoidance response.
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γ-aminobutyric acid promotes Stem Elongation in stellaria longipes : the role of ethylene
Plant Growth Regulation, 1998Co-Authors: Arumugam Kathiresan, C C Chinnappa, Jacintha Miranda, David M ReidAbstract:The response of Stems to GABA was biphasic in that lower concentrations of GABA (upto 500 µM) promoted Stem Elongation, but higher concentrations of GABA inhibited Stem Elongation. An optimal GABA concentration of 250 µM produced maximum Stem Elongation. The higher GABA concentrations also stimulated 1-aminocyclopropane-1-carboxylate (ACC) synthase (EC 4.4.1.14) mRNA accumulation and ethylene production. Results suggest that the inhibitory effect of higher GABA concentrations on Stem Elongation is partly mediated by ethylene.
Fernanda G. González - One of the best experts on this subject based on the ideXlab platform.
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floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during Stem Elongation
Functional Plant Biology, 2005Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Wheat breeding has improved yield potential increasing floret survival through higher dry matter partitioning to the spikes during the Stem Elongation phase (from terminal spikelet initiation to anthesis). We studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments applied during the Stem Elongation phase. The cultivar Buck Manantial was exposed to (1) NP+0 un-shaded (natural photoperiod and incoming radiation of the growing season), (2) NP+0 shaded (natural photoperiod but only 33% of the incoming radiation), and (3) NP+6 un-shaded (natural photoperiod extended 6 h and natural incoming radiation). Floret survival increased, depending on spikelet position, 1.1–2.5 fold under un-shaded v. shaded treatments (both under NP+0), and 1.3–1.8 fold under NP+0 v. NP+6 treatments (both un-shaded), without any impact of treatments on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were associated with duration of floret development within the Stem Elongation phase (R2 = 82%, P<0.0001). Florets may be classified into three groups: (i) those that were fertile at anthesis under all treatments (mostly the two florets F1 and F2, proximal to the rachis within the spikelet), (ii) those that reached different stages at anthesis, depending on treatment, and that contributed differentially to the number of fertile florets at anthesis (mostly the florets F3, F4 and F5, positioned in the middle of the spikelet), and (iii) those that did not contribute to the number of fertile florets under any treatment (mostly the florets ≥ F6). Degeneration of florets in group (ii) was associated with spike growth at maximum rate, explaining the strong relationship observed between spike dry weight at anthesis and number of fertile florets. However, degeneration of florets in group (iii) seemed to occur before spike growth at maximum rate. Survival of florets positioned in the middle of the spikelets could be improved by increasing spike growth through manipulation of photoperiod sensitivity during Stem Elongation.
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Floret development and survival in wheat plants exposed to contrasting photoperiod and radiation environments during Stem Elongation
Functional plant biology : FPB, 2005Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Wheat breeding has improved yield potential increasing floret survival through higher dry matter partitioning to the spikes during the Stem Elongation phase (from terminal spikelet initiation to anthesis). We studied survival of floret primodia in different spikelet positions along the spike in relation to dynamics of spike growth, when dynamics of dry matter partitioning to the spike was altered by photoperiod and shading treatments applied during the Stem Elongation phase. The cultivar Buck Manantial was exposed to (1) NP+0 un-shaded (natural photoperiod and incoming radiation of the growing season), (2) NP+0 shaded (natural photoperiod but only 33% of the incoming radiation), and (3) NP+6 un-shaded (natural photoperiod extended 6 h and natural incoming radiation). Floret survival increased, depending on spikelet position, 1.1–2.5 fold under un-shaded v. shaded treatments (both under NP+0), and 1.3–1.8 fold under NP+0 v. NP+6 treatments (both un-shaded), without any impact of treatments on the total number of initiated floret primordia. The fate of the floret primordia and its final stage at anthesis were associated with duration of floret development within the Stem Elongation phase (R2 = 82%, P
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Floret development and spike growth as affected by photoperiod during Stem Elongation in wheat
Field Crops Research, 2003Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Abstract A longer duration of Stem Elongation (from terminal spikelet initiation to anthesis) would result in a higher wheat yield potential as a consequence of the increase in both spike dry weight and number of fertile florets at anthesis. It is not clearly understood, however, which processes are involved in the increased spike dry weight and whether this variable accounts for the higher number of fertile florets when duration of Stem Elongation is modified by photoperiod treatments. As vernalization interacts with photoperiod during the Stem Elongation phase, a better understanding of the role of vernalization is also required. A field experiment was carried out using two wheat cultivars (Buck Manantial (BM) and Eureka Ferrocarril Sur (EFS)) subjected to diverse periods of vernalization (V 15 and V 50 , plants vernalized for 15 and 50 days, respectively) and exposed to different photoperiods (NP+0 and NP+6, natural and 6 h extended photoperiod, respectively) only during the Stem Elongation phase. Floret development together with Stem and spike growth during the Stem Elongation phase were studied. When the Stem Elongation phase was exposed to short photoperiod (i) duration of spike growth increased without any change in its growth rate, and (ii) most of the spike growth occurred during minimum Stem growth rate as the onset of maximum Stem growth rate was delayed. In EFS, the vernalization-sensitive cultivar, the former (i) and (ii) was true only when vernalization requirements were met. For both cultivars, the survival of the initiated floret primordia under short photoperiod increased, independently of vernalization. Both partitioning of assimilates to the spike and a direct photoperiod effect seemed to have been involved in the survival of floret primordia when the Stem Elongation phase was exposed to short photoperiod.
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Grain and floret number in response to photoperiod during Stem Elongation in fully and slightly vernalized wheats
Field Crops Research, 2003Co-Authors: Fernanda G. González, Gustavo A. Slafer, Daniel J. MirallesAbstract:Abstract The manipulation of photoperiod sensitivity during Stem Elongation (terminal spikelet initiation—anthesis) has been suggested as a means to increase wheat yield potential. Nevertheless, photoperiod sensitivity and the interaction with vernalization during that phase have not been previously explored under field conditions. Thus, a field study was carried out (i) to assess whether duration of Stem Elongation is sensitive to photoperiod experienced only during that phase, and if so (ii) to evaluate whether vernalization interacts with this photoperiod response and (iii) to determine if altering duration of Stem Elongation may influence wheat yield and its components. The experiment was a factorial combination of two vernalization treatments (15 (V15) or 50 (V50) days at 4±1 °C and 8 h photoperiod), two photoperiod regimes during Stem Elongation (natural daylength in the field (NP+0) and one daylength extension of 6 h (NP+6)) and three cultivars (Buck Manantial (BM), Eureka Ferrocarril Sur (EFS), and ProINTA Puntal (PP)). The Stem Elongation phase responded to the actual photoperiod experienced during that phase in the three cultivars, increasing its duration with shorter photoperiod. In the vernalization-sensitive cultivars EFS and PP, plants vernalized 50 days showed greater response to photoperiod than those vernalized 15 days. In the most photoperiod-sensitive cultivar (BM), as duration of Stem Elongation lengthened by exposure to less inductive photoperiod, a higher number of fertile florets at anthesis was achieved leading to an increased grain number and thereby to a higher wheat yield. These results reinforce the idea that a longer duration of Stem Elongation may offer an alternative avenue to improve yield potential in wheat.
Karl H. Mühling - One of the best experts on this subject based on the ideXlab platform.
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Grain storage protein concentration and composition of winter wheat (Triticum aestivum L.) as affected by waterlogging events during Stem Elongation or ear emergence
Journal of Cereal Science, 2018Co-Authors: Anna-catharina Wollmer, Britta Pitann, Karl H. MühlingAbstract:Abstract Maintaining grain quality of winter wheat under abiotic stresses is important for end-use functional properties. While changes in protein concentration and protein composition have been shown for drought and heat events, knowledge on effects of waterlogging on protein quality are scarce. Therefore, two winter wheat cultivars differing in baking properties were cultivated in a large-scale container experiment and exposed to waterlogging for 14 d at two different growth stages: (1) at BBCH 31 (Stem Elongation) and (2) at BBCH 51 (beginning of ear emergence). Analysis of protein concentration revealed a significant increase, but protein content per grain was decreased. Analysis of protein composition displayed significant changes after both waterlogging treatments. Waterlogging at Stem Elongation resulted in a decreased concentration of ω-gliadins. HMW glutenins increased after waterlogging at Stem Elongation and at ear emergence. In both cultivars, LMW B-type glutenins decreased after waterlogging at Stem Elongation or at ear emergence. In this study, we could show that waterlogging, occurring in generative developmental stages, enhance grain protein concentration, but not necessarily protein content, and that waterlogging causes shifts in grain protein composition.
