Grain growth and malting quality of barley. 1. Effects of heat stress and moderately high temperature

1997 ◽  
Vol 48 (5) ◽  
pp. 615 ◽  
Author(s):  
Roxana Savin ◽  
Peter J. Stone ◽  
Marc E. Nicolas ◽  
Ian F. Wardlaw
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
High Temperatures ◽  
Grain Filling ◽  
Grain Weight ◽  
Malting Quality ◽  
Very High ◽  
Moderately High Temperature

In this study, controlled-environment conditions were used to compare the effects of moderately high and very high temperatures during grain filling on grain growth and malting quality of barley. Heat stress applied from 15 to 20 days after anthesis (DAA) reduced grain weight by about 35%, whereas longer periods (15–20 days) of moderately high temperature applied from 20 DAA to maturity reduced grain weight by about 6%. Both heat stress and moderately high temperature resulted in reduced grain weight through a reduction in the duration of grain filling. Grain composition was altered by both moderately high and very high temperatures, although the changes were larger under very high temperatures. In general, there was a decrease in starch content, resulting from the reduction in both volume and number of A- and B-type starch granules. Nitrogen concentration was significantly increased only in the 30/25°C treatments, and changes in diastatic power were only minor. There was a reduction in β-glucan content, together with an increase in β-glucan degradation. However, malt extract was not significantly affected by these stresses.

Grain growth and malting quality of barley. 2. Effects of temperature regime before heat stress

1997 ◽  
Vol 48 (5) ◽  
pp. 625 ◽  
Author(s):  
Roxana Savin ◽  
Peter J. Stone ◽  
Marc E. Nicolas ◽  
Ian F. Wardlaw
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
Gradual Increase ◽  
Grain Weight ◽  
Malting Quality ◽  
Yield And Quality ◽  
Grain Yield And Quality ◽  
Very High

Short periods of very high maximum temperature (>35°C) during grain filling appear to reduce grain yield and quality in barley. Tolerance of grain yield and quality to heat stress may be increased when acclimation to high temperature occurs. Two experiments were performed to test the hypothesis that a gradual (or stepped) increase to very high temperature reduces the impact of that stress on grain growth and quality of barley, compared with a sudden increase over the same temperature range. Plants experiencing either a sudden or a gradual increase did not exhibit any differences in grain weight or malting quality, but increasing the temperature in 2 steps (so that plants were exposed to 30 or 34°C for 2 h before a 40°C heat stress) appeared to have produced acclimation, since the reduction in grain weight under the 2-step treatment was about half that of either a sudden or gradual increase in temperature. Heat stress altered grain composition in various ways. The reduction in final grain weight was strongly and linearly related to the reduction in starch content. Grain β-glucan was 4·5 ± 0·5% across treatments and experiments and was significantly reduced in the glasshouse but not in the phytotron experiment. However, β-glucan degradation was similar between treatments in both experiments. Grain nitrogen concentration was very high and similar between treatments. Consequently, diastatic power was high and there was a trend towards a reduction under heat stress. Free amino nitrogen was higher under heat stress, indicating a higher protein modification than in the controls. Malt extract was significantly reduced by heat stress in the glasshouse experiment.

The Influence of Recovery Temperature on the Effects of a Brief Heat Shock on Wheat. I. Grain Growth

1995 ◽  
Vol 22 (6) ◽  
pp. 945 ◽  
Author(s):  
PJ Stone ◽  
R Savin ◽  
IF Wardlaw ◽  
ME Nicolas
Keyword(s):  
High Temperature ◽  
Heat Shock ◽  
Grain Growth ◽  
High Temperatures ◽  
Wheat Yield ◽  
Grain Filling ◽  
Mature Individual ◽  
Very High ◽  
Moderately High Temperature ◽  
Individual Kernel

The responses of wheat yield to moderately high (20-32�C) and very high temperatures (> 32�C) have been studied separately in the literature, but not in combination, despite the fact that this is usually how elevated temperatures occur in the field. In this study, controlled environment conditions were used in order to examine the interaction of moderately high and very high temperatures during grain filling and their effect on wheat yield. Specifically, we wished to test the hypothesis that cooler conditions would facilitate greater recovery of grain growth following a brief exposure to very high temperature. To this end, wheat was exposed to either 21/16 or 40/16�C (day/night) from 15-19 days after anthesis and subsequently grown under one of three moderately high temperature regimes until maturity: 21/16, 27/22 or 30/25�C. For all moderately high temperature treatments, a brief 'heat shock' significantly reduced mature individual kernel mass by 17%, on average. In the absence of 'heat shock', increasing moderately high temperature progressively reduced mature individual kernel mass by ca 2.5% for each 1�C increase in average daily temperature. After a 'heat shock' event, however, there was not a progressive decline in mature individual kernel mass with increasing moderately high temperature. A short period of very high temperature applied early in grain filling therefore reduced the response of wheat to subsequent moderately high temperatures. We conclude that the reduction in yield caused by 'heat shock' is not alleviated by cool post-shock conditions.

Grain weight and malting quality in barley as affected by brief periods of increased spike temperature under field conditions

2002 ◽  
Vol 53 (11) ◽  
pp. 1219 ◽  
Author(s):  
Valeria S. Passarella ◽  
Roxana Savin ◽  
Gustavo A. Slafer
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
High Temperatures ◽  
Grain Filling ◽  
Grain Weight ◽  
Malting Quality ◽  
Malt Extract ◽  
Yield And Quality ◽  
Grain Nitrogen ◽  
Nitrogen Percentage

High temperature is usually one of the most important stresses during grain filling affecting both yield and quality in barley crops. In the present study, an attempt was made to assess in the field the effects of short periods of high temperature, using transparent boxes covering only the spikes, with thermostatically controlled electric resistance for increasing the temperature. Treatments consisted of 2 malting cultivars and 5 heat treatments of high temperatures (8�C above the environmental temperature for 6 h/day for 5 consecutive days) over different periods during grain filling. Final grain weight was reduced by 2–14%, depending on the timing of heat stress and the genotype. There was a significant increase in grain nitrogen percentage in both cultivars, and grain β-glucans decreased with high temperatures in Logan and were unchanged in Beka. The resulting malt extract was reduced with exposure to high temperatures, depending on the cultivar, implying that even mild heat stress may change malting performance.

Effect of Timing of Heat Stress During Grain Filling on Two Wheat Varieties Differing in Heat Tolerance. II. Fractional Protein Accumulation

1996 ◽  
Vol 23 (6) ◽  
pp. 739 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
Heat Tolerance ◽  
Grain Filling ◽  
Size Exclusion ◽  
Protein Accumulation ◽  
Wheat Varieties ◽  
Grain Filling Period ◽  
Very High

Short periods of very high temperature (> 35�C) are common during the grain filling period of wheat, and can significantly alter mature protein composition and consequently grain quality. This study was designed to determine the stage of grain growth at which fractional protein accumulation is most sensitive to a short heat stress, and to examine whether varietal differences in heat tolerance are expressed consistently throughout the grain filling period. Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley, tolerant and sensitive, respectively) were exposed to a short (5 day) period of very high temperature (40�C max, for 6 h each day) at 5-day intervals throughout grain filling, from 15 to 50 days after anthesis. Grain samples were taken throughout grain growth and analysed for protein content and composition (albumin/globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer) using size-exclusion high-performance liquid chromatography. The timing of heat stress exerted a significant influence on the accumulation of total wheat protein and its fractions, and protein fractions differed in their responses to the timing of heat stress. Furthermore, wheat genotype influenced both the sensitivity of fractional protein accumulation to heat stress and the stage during grain filling at which maximum sensitivity to heat stress occurred.

Effects of timing of heat stress and drought on growth and quality of barley grains

1999 ◽  
Vol 50 (3) ◽  
pp. 357 ◽  
Author(s):  
Roxana Savin ◽  
Marc E. Nicolas
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Quality ◽  
Grain Filling ◽  
Grain Weight ◽  
Grain Nitrogen ◽  
Barley Grains ◽  
Nitrogen Percentage ◽  
Days After Anthesis

In order to determine the importance of timing of short periods of high temperature and drought on grain weight and grain quality, a glasshouse experiment was carried out in which Schooner barley was exposed to short periods of heat stress (40˚C for 6 h/day for 5 consecutive days) or drought at early grain filling (10–15 days after anthesis, DAA), mid grain filling (20–25 DAA), or late grain filling (30–35 DAA). Individual grain weight was most sensitive to heat stress and drought treatments imposed early in grain filling and was less sensitive to later treatments. The reduction in grain weight was greater under heat stress (average 13%) than under drought in this study (average 6%). Starch was reduced in amount and quality, especially with early stresses during grain filling, but grain nitrogen percentage was similar between treatments.

Effect of Timing of Heat Stress During Grain Filling on Two Wheat Varieties Differing in Heat Tolerance. I. Grain Growth

1995 ◽  
Vol 22 (6) ◽  
pp. 927 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
Heat Tolerance ◽  
Grain Filling ◽  
Dry Matter Accumulation ◽  
Varietal Differences ◽  
Short Period ◽  
Grain Filling Period ◽  
Very High

Short periods of very high temperature (> 35�C) are common in many of the world's wheat growing areas and can be a significant factor in reducing yield and quality of wheat. This study was designed to determine the stage at which grain growth is most sensitive to a short period of high temperature and to examine whether varietal differences in heat tolerance are expressed throughout the whole grain-filling period. Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley) were exposed to a short (5 days) period of very high temperature (40�C max. for 6 h each day) at 5-day intervals throughout grain filling, starting from 15 days after anthesis (DAA) and concluding at 50 DAA. Responses of grain dry matter accumulation and water content to high temperature were monitored throughout grain filling, and the results compared with controls maintained at 21/16�C day/night. Varietal differences in heat tolerance were expressed throughout the grain-filling period. Mature individual kernel mass was most sensitive to heat stress applied early in grain filling and became progressively less sensitive throughout grain filling, for both varieties. Reductions in mature kernel mass resulted primarily from reductions in duration rather than rate of grain filling.

Effects of Short Periods of Drought and High Temperature on Grain Growth and Starch Accumulation of Two Malting Barley Cultivars

1996 ◽  
Vol 23 (2) ◽  
pp. 201 ◽  
Author(s):  
R Savin ◽  
ME Nicolas
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Growth ◽  
Grain Filling ◽  
Grain Weight ◽  
Maximum Temperature ◽  
Starch Accumulation ◽  
Nitrogen Accumulation ◽  
Barley Cultivars ◽  
High Temperature Maximum

Short periods (3-5 days) of high maximum temperature (>35�C), often accompanied by drought, commonly occur during grain filling of cereals. Short periods of high temperature have been shown to reduce grain weight and baking quality in wheat, but little is known about their effects on barley. Consequently, we examined the effects of high temperature and drought, alone or combined, on grain growth for two barley cultivars, Schooner and Franklin. Treatments started 15 days after anthesis and consisted of the factorial combination of three temperatures and three water regimes. The high temperature (maximum 40�C for 6 h day-1) and drought treatments were maintained for 5 or 10 days. Drought reduced individual grain weight much more (ca 20%) than high temperature (ca 5%) for both cultivars. Franklin appeared to be more sensitive to heat stress than Schooner. The reduction in individual grain weight was greatest when both stresses were combimed (ca 30%). The reduction in mature grain weight under high temperature was due to a reduction in duration of grain growth for Schooner and to a reduction in both rate and duration of grain growth for Franklin (8-12%). The reduction in duration of grain growth was the most important cause of reduced grain weight at maturity under drought alone (12-25%) or combined with high temperature (25-33%). Nitrogen content per grain was quite high and similar for all treatments, and nitrogen percentage increased when stress was severe enough to reduce starch accumulation, confirming that starch accumulation is more sensitive to post- anthesis stress than nitrogen accumulation. We conclude that drought, particularly when combined with high temperature, is more likely than heat stress to cause large reductions in grain weight of barley under field conditions.

Effects of a period of high temperature during grain filling on the grain growth characteristics and malting quality of three Australian malting barleys

1998 ◽  
Vol 49 (8) ◽  
pp. 1287 ◽  
Author(s):  
M. A. B. Wallwork ◽  
S. J. Logue ◽  
L. C. MacLeod ◽  
C. F. Jenner
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Dry Matter ◽  
Protein Modification ◽  
Water Extract ◽  
Grain Filling ◽  
Hot Water ◽  
Grain Weight ◽  
Starch Accumulation ◽  
Heat Treated

Short periods of high temperatures (up to 35°C) during mid grain filling appear to reduce yield and quality in barley. Plants of 3 malting barley varieties, Schooner, Arapiles, and Sloop (a new South Australian malting variety), were grown under constant environment conditions from germination to maturity and exposed to 5 days of high temperatures (up to 35°C) during mid grain filling. Schooner and Sloop showed similar patterns of accumulation of dry matter under control conditions (21°C/16°C, day/night temperature) and in response to high temperatures. In all varieties, the reduction in starch accumulation represented the most significant detrimental effect of high temperature and made the greatest contribution to the reduction in final grain weight. The reduction in absolute grain nitrogen (N) in heat-treated Arapiles grains represents a potentially important response under high temperature conditions. In this study, water loss did not have a decisive role in the termination of grain filling. Continued accumulation of endosperm dry matter at low moisture levels suggested that water distribution and/or components of water potential may be more important than overall water content in the cessation of grain filling. Final grain composition depended not only on the amount of endosperm storage component present in the grain but also on the contribution of the non-endosperm components (including the embryo and husk) to final grain dry weight. In some cases, changes in the contribution made by the non-endosperm components of the grain to final grain weight masked important high temperature effects on key endosperm storage components. Hot water extract (HWE) values were similar within treatments and ranged from 73% to 78%. High temperature exposure reduced HWE for all varieties. Malt b-glucan was lower in heat-treated grains than in control grains. Despite relatively high malt protein levels in all varieties, higher free amino N levels in heat-treated grains indicated a higher protein modification than in control grains.

Are temperature effects on weight and quality of barley grains modified by resource availability?

2008 ◽  
Vol 59 (6) ◽  
pp. 510 ◽  
Author(s):  
Valeria S. Passarella ◽  
Roxana Savin ◽  
Gustavo A. Slafer
Keyword(s):  
Heat Stress ◽  
Resource Availability ◽  
Grain Filling ◽  
Grain Weight ◽  
Malting Quality ◽  
Malt Extract ◽  
Nitrogen Fertilisation ◽  
Wide Range ◽  
Barley Grains ◽  
Source Sink

Under field conditions the occurrence of brief periods of moderately high (30–32°C) and very high temperatures (>35°C) is quite common during grain filling in small-grain cereals. These events occur under a wide range of different management and environmental conditions, such as different nitrogen supplies and source–sink ratios after flowering. The objective of the present work was to study whether the effect of a brief heat stress is modified by resource availability for the growing grains. We subjected spikes of barley 10 days after flowering to a heat treatment in factorial combination with different nitrogen availabilities and source–sink ratios during post-flowering to determine effects on grain weight and major malting quality attributes. Grain weight and screening percentage (proportion of grains <2.5 mm) were reduced by the mild heat stress. However, the magnitude of the effect was dependent on the nitrogen fertilisation and the source–sink treatments in which the heat stress was imposed. Grain protein and β-glucan percentages were increased by both nitrogen fertilisation and heat stress. Again, the magnitude of the increase was dependent upon the availability of resources. There was a trend to reduce malt extract in all treatments with respect to the control, but the reduction was only statistically significant with heat stress.

Effect of timing of heat stress during grain filling in two wheat varieties under moderate and very high temperature

2015 ◽  
Vol 75 (1) ◽  
pp. 121
Author(s):  
W. F. Song ◽  
L. J. Zhao ◽  
X. M. Zhang ◽  
Y. M. Zhang ◽  
J. L. Li ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Grain Filling ◽  
Wheat Varieties ◽  
Very High
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