Do wheat breeders have suitable genetic variation to overcome short coleoptiles and poor establishment in the warmer soils of future climates?

2016 ◽  
Vol 43 (10) ◽  
pp. 961 ◽  
Author(s):  
Greg J. Rebetzke ◽  
Bangyou Zheng ◽  
Scott C. Chapman

Increases in air and soil temperatures will impact cereal growth and reduce crop yields. Little is known about how increasing temperatures will impact seedling growth and crop establishment. Climate forecast models predict that by 2060, mean and maximum air temperatures in the Australian wheatbelt will increase by 2−4°C during the March–June sowing period, and particularly at lower latitudes. Concomitant increases in soil temperature will shorten coleoptile length to reduce crop establishment, particularly where deep sowing to access sub-surface moisture. Mean coleoptile length was reduced in commercial wheat (Triticum aestivum L.) germplasm with increasing soil temperature (106 mm and 51 mm at 15°C and 31°C, respectively). Coleoptile lengths of modern semidwarf varieties were significantly (P < 0.01) shorter than those of older tall wheats at 15°C (95 mm and 135 mm) and 31°C (46 mm and 70 mm). A 12-parent diallel indicated large additive and small non-maternal genetic effects for coleoptile length at 15°C and 27°C. Large genotype rank changes for coleoptile length across temperatures (rs = 0.37, P < 0.05) contributed to smaller entry-mean heritabilities (0.41–0.67) to reduce confidence in selection for long-coleoptile genotypes across contrasting temperatures. General combining ability effects were strongly correlated across temperatures (rp = 0.81, P < 0.01), indicating the potential of some donors in identification of progeny with consistently longer coleoptiles. Warmer soils in future will contribute to poor establishment and crop failure, particularly with deep-sown semidwarf wheat. Breeding long-coleoptile genotypes with improved performance will require targeted selection at warmer temperatures in populations incorporating novel sources of reduced height and greater coleoptile length.

2015 ◽  
Vol 12 (1) ◽  
pp. 23-30 ◽  
Author(s):  
C. Bertrand ◽  
L. González Sotelino ◽  
M. Journée

Abstract. Soil temperatures at various depths are unique parameters useful to describe both the surface energy processes and regional environmental and climate conditions. To provide soil temperature observation in different regions across Belgium for agricultural management as well as for climate research, soil temperatures are recorded in 13 of the 20 automated weather stations operated by the Royal Meteorological Institute (RMI) of Belgium. At each station, soil temperature can be measured at up to 5 different depths (from 5 to 100 cm) in addition to the bare soil and grass temperature records. Although many methods have been developed to identify erroneous air temperatures, little attention has been paid to quality control of soil temperature data. This contribution describes the newly developed semi-automatic quality control of 10-min soil temperatures data at RMI.


2013 ◽  
Vol 10 (7) ◽  
pp. 4465-4479 ◽  
Author(s):  
K. L. Hanis ◽  
M. Tenuta ◽  
B. D. Amiro ◽  
T. N. Papakyriakou

Abstract. Ecosystem-scale methane (CH4) flux (FCH4) over a subarctic fen at Churchill, Manitoba, Canada was measured to understand the magnitude of emissions during spring and fall shoulder seasons, and the growing season in relation to physical and biological conditions. FCH4 was measured using eddy covariance with a closed-path analyser in four years (2008–2011). Cumulative measured annual FCH4 (shoulder plus growing seasons) ranged from 3.0 to 9.6 g CH4 m−2 yr−1 among the four study years, with a mean of 6.5 to 7.1 g CH4 m−2 yr−1 depending upon gap-filling method. Soil temperatures to depths of 50 cm and air temperature were highly correlated with FCH4, with near-surface soil temperature at 5 cm most correlated across spring, fall, and the shoulder and growing seasons. The response of FCH4 to soil temperature at the 5 cm depth and air temperature was more than double in spring to that of fall. Emission episodes were generally not observed during spring thaw. Growing season emissions also depended upon soil and air temperatures but the water table also exerted influence, with FCH4 highest when water was 2–13 cm below and lowest when it was at or above the mean peat surface.


1952 ◽  
Vol 5 (2) ◽  
pp. 303 ◽  
Author(s):  
ES West

Soil temperatures recorded at Griffith over an 8 year period at a depth ranging from 1 in. to 8 ft. have been examined and compared with air temperatures. The observed fluctuations m the soil temperatures fit closely the theoretical equation for the propagation of a simple harmonic temperature wave into the so11. The diffusivity of the sol1 has been deduced and compared with values found by other workers in other localities. The annual wave of the daily mean temperature at the surface of the soil has been deduced and compared with the annual wave of the dally mean air temperature and the differences in the means, amplitudes, and phase displacements have been discussed.


2003 ◽  
Vol 83 (1) ◽  
pp. 89-98 ◽  
Author(s):  
F. J. Larney ◽  
T. Ren ◽  
S. M. McGinn ◽  
C. W. Lindwall ◽  
R. C. Izaurralde

Soil and crop management practices and their effects on surface residue levels can modify soil temperature. Our study investigated the effect of rotation, tillage and row spacing on near-surface (0.025 m) soil temperature under winter wheat (Triticum aestivum L.) in 1993-1994 and 1994-1995. The main treatment was winter wheat rotation: continuous winter wheat (WW); winter wheat-canola (Brassica campestris L.) (WC) or winter wheat-fallow (WF)] with tillage sub-treatments of conventional tillage (CT) vs. zero tillage (ZT) and row spacing treatments of uniform row (UR) vs. paired row (PR) spacing. From fall 1993 to spring 1994, ZT was cooler than CT by 1.2°C on the WC rotation, 1.1°C on WW and 0.4°C on the WF rotation. From fall 1994 to spring 1995, the magnitude of tillage differences was lower on all three rotations with ZT being cooler than CT by 0.1–0.9°C. The magnitude of the row spacing effect on soil temperature was less than that of the tillage effect. Extreme differences in soil temperature due to tillage were generally higher (1.0–4.9°C) on the WW and WC than the WF rotation (0.6–2.5°C) due to the presence of more crop residue. Results demonstrate that while ZT promotes overall cooler soils under winter wheat from fall to late spring, especially on continuously cropped (WW, WC) rotations, it also allows moderation of soil temperatures during extremely cold periods. Key words: Soil temperature, winter wheat, rotation, tillage, row spacing


1997 ◽  
Vol 77 (1) ◽  
pp. 181-188
Author(s):  
A. L. Darwent ◽  
L. P. Lefkovitch ◽  
P. F. Mills

Field and controlled environment experiments were conducted at Beaverlodge, Alberta to determine the effect of soil temperature, seeding depth and cultivar on wheat (Triticum aestivum L.) tolerance to ethalfluralin. In one experiment, ethalfluralin was applied and incorporated, and wheat was seeded at several depths in late April/early May when soil temperatures were lowest or in late May when soil temperatures had increased. Mean 3-yr wheat yields decreased by 45% as the rate of ethalfluralin increased from 0 to 0.75 kg ha−1 and by 21% as the depth of seeding increased from 4 to 12.5 cm but the effect of ethalfluralin on yields was similar regardless of the soil temperature (time of seeding). Mean plant density decreased by 55% as the rate of ethalfluralin increased and by 25% as the depth of seeding increased. Reductions in mean plant density from ethalfluralin were slightly greater when seeded into the warmer soils. In another experiment, the effect of ethalfluralin on the yields of three wheat cultivars, Laura, Conway and Biggar was similar, i.e. the cultivar × rate of ethalfluralin interaction was not significant. However, the mean plant density of Biggar, averaged over rates of ethalfluralin, was less than that of the other cultivars in 1 of 2 yr. In a controlled environment experiment, the oven-dry weight and percent emergence of wheat shoots of the cultivars, Katepwa, Laura and Conway, seeded at 1.5 or 4 cm into soils containing ethalfluralin at concentrations of 0 to 4 ppm and maintained at temperatures of 4.5 or 15 °C, were reduced by decreases in temperature and increases in the rate of herbicide and depth of seeding. However, the interaction of soil temperature × rate of ethalfluralin was not significant for the oven-dry weight of the wheat shoots and the reduction in percent emergence of the wheat shoots as the rate of ethalfluralin increased was only slightly greater at 4.5 °C than at 15 °C. These results indicate that soil temperature and cultivar selection have a minor effect on wheat tolerance to ethalfluralin while herbicide concentration and depth of seeding have a major impact. Key words: Ethalfluralin, wheat, seeding depth, soil temperature, cultivar


1977 ◽  
Vol 57 (4) ◽  
pp. 1141-1149 ◽  
Author(s):  
C. J. ANDREWS ◽  
M. K. POMEROY

The survival of winter cereal cultivars of contrasting cold hardiness was determined after various modifications of the winter environment at two locations in 3 yr at Ottawa, Ontario. Artificially produced ice covers reduced survival in all cases, and the severest damage was associated with high soil moisture at the time of ice formation. Maintenance of soil temperatures close to zero by replacement of an insulating snow cover over ice increased average survival by about 10% compared with non-insulated plots. Naturally formed ice covers were less damaging than those artificially produced, and in one case formation of an ice cover protected plants from very low air temperatures, resulting in greater survival than in control plots. Total removal of snow in January was severely damaging, while accumulation of snow at a snowfence allowed increased survival of all cultivars. The correlation between cold hardiness and survival in ice treatments was significant, but one wheat (Triticum aestivum L.) cultivar showed better survival than comparable wheats in a number of ice-stressed treatments, while not showing superiority in unstressed or controlled environment conditions.


FLORESTA ◽  
2004 ◽  
Vol 34 (2) ◽  
Author(s):  
Leocadio Grodzki ◽  
Ronaldo Viana Soares ◽  
Antonio Carlos Batista ◽  
Paulo Henrique Caramori

O sistema agroflorestal da bracatinga utiliza queima após o corte e retirada da madeira, dando lugar à semeadura de espécies agrícolas. A queima controlada altera a temperatura do ar e do solo. A mudança de refletividade da superfície é mais rápida que dos reflorestamentos próximos. A transformação das folhas e galhos secos em cinza após a queima, faz com que haja mudanças do albedo, alterando o balanço energético. Os resultados mostram temperaturas do ar de 600ºC por 20-40 segundos a 1 cm do solo e de 100 a 300°C a 60 e 160cm do solo, respectivamente, durante 1 minuto. Temperaturas de 100ºC ao nível do solo residiram por mais de 3 minutos. A temperatura do solo não foi afetada a 2,5cm de profundidade. Durante a queima, a temperatura se elevou em 1ºC. O albedo de 0,24 antes da queima, passou para 0,21 logo após a queima. Após 60 dias, o albedo voltou a 0,24 devido a recomposição da vegetação. FIRE EFECTS ON SOME MICROMETEOROLOGICAL VARIABLES IN A BRACATINGA (Mimosa scabrella, Benth.) FOREST, COLOMBO, PR Abstract The bracatinga agriculture-forest systems adopted by farmers consists on burning the residues after wood’s harvesting prior to sowing the crops. This procedure is repeated each 6 to 8 years in the same area. The prescribed burning changes air and soil temperatures. Changes in reflectivity are faster then in the surrounding forest areas. Transforming leaves and branches into ashes after burning changes the albedo of the surface, altering the energetic balance. Results showed air temperatures of 600°C during 20 to 40 seconds, 1cm above the soil surface, and 100 to 300°C at 60 and 160cm above the soil surface, during 1 minute. Temperatures over 100°C on the soil surface were observed for more than 3 minutes. Soil temperature was not affected at 2.5cm depth; during burning, the temperature raised only 1ºC. The surface albedo that was 0,24 before the burning changed to 0,21 after burning and returned to 0.24 sixty days after the burning due to the vegetation regeneration.


Soil Research ◽  
2011 ◽  
Vol 49 (4) ◽  
pp. 305 ◽  
Author(s):  
Brian Horton ◽  
Ross Corkrey

Soil temperatures are related to air temperature and rainfall on the current day and preceding days, and this can be expressed in a non-linear relationship to provide a weighted value for the effect of air temperature or rainfall based on days lag and soil depth. The weighted minimum and maximum air temperatures and weighted rainfall can then be combined with latitude and a seasonal function to estimate soil temperature at any depth in the range 5–100 cm. The model had a root mean square deviation of 1.21–1.85°C for minimum, average, and maximum soil temperature for all weather stations in Australia (mainland and Tasmania), except for maximum soil temperature at 5 and 10 cm, where the model was less precise (3.39° and 2.52°, respectively). Data for this analysis were obtained from 32–40 Bureau of Meteorology weather stations throughout Australia and the proposed model was validated using 5-fold cross-validation.


1998 ◽  
Vol 78 (3) ◽  
pp. 493-509 ◽  
Author(s):  
Dale S. Nichols

Soil temperature strongly influences physical, chemical, and biological activities in soil. However, soil temperature data for forest landscapes are scarce. For 6 yr, weekly soil temperatures were measured at two upland and four peatland sites in north central Minnesota. One upland site supported mature aspen forest, the other supported short grass. One peatland site was forested with black spruce, one supported tall willow and alder brush, and two had open vegetation — sedges and low shrubs. Mean annual air temperature averaged 3.6 °C. Mean annual soil temperatures at 10- to 200-cm depths ranged from 5.5 to 7.6 °C among the six sites. Soils with open vegetation, whether mineral or peat, averaged about 1 °C warmer annually and from 2 to 3 °C warmer during summer than the forested soils. The tall brush peatland was cooler than all other sites due to strong groundwater inputs. The mineral soils warmed more quickly in the spring, achieved higher temperatures in the summer, and cooled more quickly in the fall than the peat soils; however, the greatest temperature differences between mineral and peat soils occurred at or below 50 cm. In the upper 20 cm, vegetation and groundwater had greater effects on temperature than did soil type (mineral or peat). Summer soil temperatures were higher, relative to air temperature, during periods of greater precipitation. This effect was minimal at upland sites but substantial in the peatlands. In spite of the persistent sub-freezing air temperatures typical of Minnesota winters, significant frost developed in the soils only in those years when severe cold weather arrived before an insulating cover of snow had accumulated. Key words: Soil temperature, vegetation effects, forest soils, groundwater, peatlands


1998 ◽  
Vol 78 (2) ◽  
pp. 291-300 ◽  
Author(s):  
Margaret G. Schmidt ◽  
Aynslie E. Ogden ◽  
Kenneth P. Lertzman

In this study we attempted to determine if vine maple priority gaps show similar trends in temperature and moisture status to those reported in the literature for treefall gaps and whether temperature and moisture status differed between microtopographic positions (pits and mounds). Biweekly measurements of mid-day soil and air temperature, moisture contents at 30-, 50- and 80-cm depths, and depths to the groundwater table were made in pit and mound locations within six vine maple priority gaps paired with six conifer canopy sites. Trends did not follow those found in treefall gaps: vine maple gaps had similar mid-day temperature and moisture status to the surrounding conifer forest. Larger gaps had higher mid-day air temperatures in the summer, higher mid-day soil temperatures in the spring and summer, and greater amounts of throughfall in the spring and summer than smaller gaps. Trends in mid-day soil temperature and moisture status for pit and mound microtopography followed those reported in the literature. Pits were significantly cooler in summer and warmer in winter than mounds and pits were wetter than mounds in all seasons. This study suggests that soil microtopography has an effect on soil climate that overwhelms the influence of vine maple gaps. Key words: Vine maple, canopy gap, soil moisture, soil temperature, microtopography, pits and mounds


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