We aimed to study impact of drought stress on physiological traits of field grown 8 durum and 14 bread wheat genotypes. Drought caused decrease of leaf gas exchange parameters—photosynthesis rate (P n), stomatal conductance (g s), and transpiration rate (E), an increase of intercellular CO 2 concentration (C i). Area (LA) and dry mass of leaves per stem, leaf area index (LAI) of genotypes significantly reduced from booting to watery ripe stages. Water deficiency led to a decrease of chlorophyll a, b (Chla,b) and carotenoids (Car (x+c) content, relative water content (RWC). Water stress more affected on LA than leaf dry mass of wheat genotypes, leaf specific mass (LSM) increased. The Chl(a+b) content, P n and yield of bread wheat genotypes were relatively higher than durum wheat ones. Physiological traits may be reliable for selection of drought tolerant wheat genotypes.
Plants are often subjected to periods of unfavorable conditions (drought, high light and temperature) during their life cycle in the field. Drought is the most severe stress and the main cause of significant losses in growth, productivity of crop plants, and finally their yields [
For identifying of drought tolerance of wheat, we need to test a number of genotypes in the field. It is revealed that varieties, with higher leaf turgor and relative water content under stress conditions, are more drought tolerant and give higher yield than others [
Eight durum wheat genotypes (Garagylchyg 2,Vugar, Shiraslan 23, Barakatli 95, Alinja 84, Tartar, Sharg, Gyrmyzybugda), fourteen bread wheat genotypes (Nurlu 99, Gobustan, Akinchi 84, Giymatli 2/17, Gyrmyzy gul1, Azamatli 95, Tale 38, Ruzi 84, Pirshahin1, 12ndFAWWON№97, 4thFEFWSN№50, Gunashli, Dagdash, Saratovskaya29) were employed in this study. Wheat genotypes were grown in the field of Plant Physiology and Biotechnology Department of Research Institute of Crop Husbandry, Azerbaijan, during the growing season of 2013-2014. Sowing was down 25-26 October, at an average density 400 seeds∙m−2 with self-propelled mechanical planter in 1 m × 10 m plots, consisting of 7 rows placed 15 cm apart. Each genotype was sown with three replications both under irrigated and rain-fed conditions. Irrigated plots were watered with the appearance of seedlings, at stem elongation, and grain filling stages. Rain-fed plots were not watered during ontogeny. Soil moisture content (% of the field capacity) was determined in the 0 - 20, 20 - 40, 40 - 60 cm depths, and was about 60.4% under irrigated, 33% under rain-fed conditions during booting stage, 60% under irrigated, 28% under rain-fed conditions during watery ripe stage.
Gas exchange parameters were measured with a Portable Photosynthesis System LI-6400XT (LI-COR Biosciences, Lincoln, NE, USA), equipped with 6 cm2 leaf chamber. Light intensity measured by using Light-Meter LI-250A (LI-COR Biosciences) equipped with Pyranometer PY 71968 (LI-COR Biosciences). A lux meter data (klux) is converted into photosynthetically active radiation (PAR) unit (µmol photons m−2∙s−1) multiplying by 1000 and then divided into 54. Gas exchange measurements done during booting stage (Feekes Stage 10) and watery ripe stage (Feekes Stage 10.5.4). Measurements carried out between 10:00 and 12:00 a.m. Data logging started after 45 seconds of insertion the leaf into chamber. Five-seven replicate measurements were conducted for each genotype. As
LA measured with an area meter (AAC-400, Hayashi Denkon Co, LTD, Japan). Data corresponds to the LA
09:00 a.m. | 11:00 a.m. | 13:00 a.m. | 15:00 a.m. | 17:00 a.m. | 18:00 a.m. | 19:00 a.m. | |
---|---|---|---|---|---|---|---|
PAR, µmol photons m−2∙s−1 | 1003 | 1520 | 1706 | 1561 | 1391 | 895 | 667 |
Pn, µmol CO2 m−2∙s−1 | 10.68 ± 1.4 | 13.55 ± 0.36 | 17.9 ± 0.94 | 16.98 ± 1.23 | 11.56 ± 0.55 | 5.95 ± 0.62 | 3.79 ± 0.32 |
per stem. The flag leaf RWC determined gravimetrically. Immediately after cutting leaves were preserved within plastic bags and in time transferred to the laboratory to determine fresh weight (FW). Turgid weight (TW) was determined after saturating leaves in distilled water for 24 h at room temperature in dark place. After saturating, leaves were carefully blotted dried with tissue paper. Dry weight (DW) was measured after oven drying the leaves samples at 105˚C for 24 h. RWC calculated by using the following formula:
High Pn is considered to be one the most important breeding strategies for crop improvement [
Water deficit led to a decrease in gs (
The lowest decrease in gs during both stages observed in genotypes Shiraslan 23, Sharg, Gyrmyzybugda, Gyrmyzy gul 1, 12ndFAWWON№97, Gunashli, 4thFEFWSN№50 and Dagdash. We observed an increase of gs in genotypes Gyrmyzybugda, Dagdash, Saratovskaya 29 during watery ripe stage.
We found an increase in Ci under drought conditions which strongly expressed in the stage of watery ripe (
Water stress led to decrease in E (
The RWC is an important indicator of the state of water balance of a plant. The RWC of flag leaf of most genotypes was greater than 80% during post anthesis grain formation stage under irrigated condition (
We observed an increase in RWC of genotype Sharg. The RWC of genotypes Vugar, Tartar, Gyrmyzybugda, Giymatli 2/17, Azamatli 95, Tale 38, Ruzi 84, Pirshahin1, 12ndFAWWON97, 4thFEFWSN50, Dagdash, Saratovskaya 29 retained at relatively high level under rain-fed conditions. This may be due to accumulation of osmotic active compouds, regulation of water loss or deep root system.
Drought caused reduction of Chl (a+b) and Car (x+c) contents. The Chl(a+b) content was greater in the flag leaf of bread wheat genotypes than durum wheat ones (
influence on Chl (a+b) content than the content of Car (x+c).
Assimilation area of leaves were greater in genotypes of durum wheat than in genotypes of bread wheat ones (
As expected large LA of durum wheat genotypes accumulated higher dry matter (
LAI was higher in genotypes Garagylchyg 2, Vugar, Shiraslan 23, Barakatli 95, Giymatli 2\17, Gyrmyzy gul 1, Tale 38, 4thFEFWSN№50 under irrigated condition during booting stage (
Wheat genotypes | Chl a mg∙g−1 dw | Chl b mg∙g−1 dw | Chl (a+b) mg∙g−1 dw | Car (x+c) mg∙g−1 dw | Chl a/b | Chl (a+b)/ Car (x+c) | |
---|---|---|---|---|---|---|---|
Triticum durum Desf. | |||||||
Garagylchyg 2 | I | 6.34 | 2.56 | 8.9 | 1.48 | 2.47 | 6.01 |
R-f | 3.08 | 1.75 | 4.83 | 0.63 | 1.77 | 7.66 | |
Vugar | I | 6.29 | 2.70 | 8.98 | 1.33 | 2.33 | 6.75 |
R-f | 6.04 | 2.70 | 8.74 | 1.40 | 2.23 | 6.24 | |
Shiraslan23 | I | 5.54 | 2.82 | 8.36 | 1.02 | 1.96 | 8.23 |
R-f | 4.16 | 2.15 | 6.31 | 1.01 | 1.93 | 6.27 | |
Barakatli95 | I | 6.85 | 2.91 | 9.75 | 1.53 | 2.36 | 6.37 |
R-f | 5.36 | 2.40 | 7.76 | 1.15 | 2.23 | 6.75 | |
Alinja84 | I | 5.68 | 2.67 | 8.36 | 1.24 | 2.13 | 6.73 |
R-f | 4.72 | 2.35 | 7.06 | 0.98 | 2.01 | 7.16 | |
Tartar | I | 10.04 | 3.99 | 14.02 | 2.08 | 2.52 | 6.74 |
R-f | 4.57 | 1.83 | 6.40 | 1.09 | 2.50 | 5.87 | |
Sharg | I | 5.16 | 1.93 | 7.08 | 1.46 | 2.67 | 4.84 |
R-f | 3.97 | 1.47 | 5.44 | 1.36 | 2.69 | 4.01 | |
Gyrmyzybugda | I | 5.84 | 2.07 | 7.91 | 1.47 | 2.81 | 5.38 |
R-f | 5.04 | 1.79 | 6.83 | 1.49 | 2.81 | 4.57 | |
Triticum aestivum L. | |||||||
Nurlu 99 | I | 6.06 | 2.42 | 8.48 | 1.45 | 2.51 | 5.83 |
R-f | 3.12 | 1.21 | 4.33 | 1.03 | 2.59 | 4.22 | |
Gobustan | I | 7.82 | 3.04 | 10.85 | 1.65 | 2.57 | 6.57 |
R-f | 3.23 | 1.35 | 4.58 | 0.82 | 2.40 | 5.56 | |
Akinchi 84 | I | 7.98 | 3.12 | 11.10 | 1.87 | 2.55 | 5.92 |
R-f | 4.77 | 1.90 | 6.67 | 1.43 | 2.51 | 4.67 | |
Giymatli 2/17 | I | 6.63 | 2.87 | 9.50 | 1.37 | 2.31 | 6.93 |
R-f | 4.97 | 1.78 | 6.75 | 1.18 | 2.78 | 5.74 | |
Gyrmyzygul 1 | I | 8.02 | 3.10 | 11.12 | 1.70 | 2.59 | 6.54 |
R-f | 5.99 | 2.32 | 8.31 | 1.33 | 2.59 | 6.24 | |
Azamatli95 | I | 5.88 | 2.37 | 8.25 | 1.29 | 2.48 | 6.39 |
R-f | 5.17 | 2.17 | 7.34 | 1.34 | 2.39 | 5.48 | |
Tale38 | I | 7.52 | 3.01 | 10.53 | 1.58 | 2.50 | 6.65 |
R-f | 5.86 | 2.26 | 8.12 | 1.44 | 2.59 | 5.62 | |
Ruzi 84 | I | 5.92 | 2.23 | 8.15 | 1.6 | 2.66 | 5.09 |
R-f | 4.23 | 1.72 | 5.95 | 1.25 | 2.47 | 4.75 | |
Pirshahin 1 | I | 5.31 | 2.56 | 7.87 | 1.21 | 2.08 | 6.50 |
R-f | 3.58 | 1.49 | 5.07 | 1.31 | 2.41 | 4.48 | |
12ndFAWWON №97 | I | 6.48 | 2.86 | 9.34 | 1.40 | 2.27 | 6.68 |
R-f | 5.25 | 2.24 | 7.49 | 1.41 | 2.34 | 5.30 | |
Gunashli | I | 6.46 | 2.44 | 8.90 | 1.59 | 2.64 | 5.60 |
R-f | 3.13 | 1.16 | 4.28 | 1.25 | 2.70 | 3.42 | |
4thFEFWSN №50 | I | 6.97 | 2.94 | 9.90 | 1.61 | 2.37 | 6.16 |
R-f | 5.42 | 2.18 | 7.60 | 1.41 | 2.48 | 5.40 | |
Dagdash | I | 7.34 | 2.77 | 10.11 | 1.73 | 2.65 | 5.83 |
R-f | 6.35 | 2.38 | 8.73 | 1.87 | 2.66 | 4.66 | |
Saratovskaya 29 | I | 7.20 | 2.73 | 9.93 | 1.71 | 2.64 | 5.82 |
R-f | 6.79 | 2.59 | 9.38 | 1.65 | 2.62 | 5.67 |
The gm calculated from Pn/Ci ratio, WUE calculated from Pn/E ratio, and LSM calculated from the ratio of leaf dry mass to LA (
Genotypes | gm mol CO2 m−2∙s−1 | WUE. µmol CO2 mmol−1 H2O | LSM. mg∙mm−2 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Booting Irrigated | Booting Rain fed | Watery ripe Irrigated | Watery ripe Rain fed | Booting Irrigated | Booting Rain fed | Watery ripe-Irrigated | Watery ripe Rain fed | Booting Irrigated | Booting Rain fed | Watery ripe Irrigated | Watery ripe Rain fed | |||
Triticum durum (Desf.) | ||||||||||||||
Garagylchyg 2 | 0.034 | 0.019 | 0.019 | 0.010 | 5.27 | 5.18 | 1.54 | 1.10 | 0.044 | 0.052 | 0.068 | 0.069 | ||
Vugar | 0.021 | 0.013 | 0.020 | 0.008 | 4.29 | 5.07 | 1.74 | 0.83 | 0.042 | 0.045 | 0.059 | 0.061 | ||
Shiraslan 23 | 0.042 | 0.025 | 0.017 | 0.012 | 6.68 | 5.70 | 1.81 | 1.35 | 0.043 | 0.044 | 0.053 | 0.051 | ||
Barakatli 95 | 0.037 | 0.020 | 0.014 | 0.004 | 5.08 | 4.39 | 1.66 | 0.61 | 0.039 | 0.039 | 0.055 | 0.073 | ||
Alinja 84 | 0.041 | 0.026 | 0.023 | 0.007 | 5.07 | 4.80 | 2.38 | 1.09 | 0.043 | 0.047 | 0.048 | 0.066 | ||
Tartar | 0.043 | 0.036 | 0.031 | 0.009 | 5.85 | 6.22 | 2.03 | 1.16 | 0.055 | 0.055 | 0.032 | 0.064 | ||
Sharg | 0.068 | 0.038 | 0.011 | 0.010 | 3.26 | 2.99 | 1.02 | 1.05 | 0.050 | 0.049 | 0.054 | 0.073 | ||
Gyrmyzybugda | 0.043 | 0.027 | 0.021 | 0.020 | 3.06 | 2.30 | 1.61 | 1.60 | 0.043 | 0.042 | 0.057 | 0.066 | ||
Triticum aestivum L. | ||||||||||||||
Nurlu 99 | 0.060 | 0.026 | 0.009 | 0.003 | 5.10 | 4.47 | 1.29 | 0.57 | 0.044 | 0.048 | 0.057 | 0.061 | ||
Gobustan | 0.061 | 0.026 | 0.012 | 0.010 | 4.54 | 3.86 | 1.58 | 1.09 | 0.041 | 0.049 | 0.068 | 0.078 | ||
Akinchi 84 | 0.062 | 0.021 | 0.022 | 0.008 | 4.90 | 3.71 | 1.74 | 1.03 | 0.044 | 0.051 | 0.064 | 0.078 | ||
Giymatli 2/17 | 0.063 | 0.044 | 0.035 | 0.013 | 5.28 | 5.11 | 2.05 | 1.07 | 0.048 | 0.042 | 0.058 | 0.067 | ||
Gyrmyzy gul1 | 0.047 | 0.035 | 0.025 | 0.018 | 4.32 | 5.67 | 1.71 | 1.57 | 0.040 | 0.043 | 0.056 | 0.069 | ||
Azamatli 95 | 0.056 | 0.030 | 0.016 | 0.013 | 4.45 | 4.00 | 1.16 | 1.20 | 0.047 | 0.050 | 0.068 | 0.075 | ||
Tale 38 | 0.046 | 0.043 | 0.029 | 0.008 | 4.40 | 4.28 | 1.65 | 0.91 | 0.044 | 0.046 | 0.054 | 0.069 | ||
Ruzi 84 | 0.051 | 0.034 | 0.029 | 0.006 | 4.10 | 4.31 | 1.96 | 0.85 | 0.049 | 0.060 | 0.069 | 0.099 | ||
Pirshahin 1 | 0.073 | 0.059 | 0.032 | 0.017 | 4.56 | 4.69 | 2.20 | 1.34 | 0.053 | 0.054 | 0.077 | 0.113 | ||
12ndFAWWON97 | 0.031 | 0.024 | 0.018 | 0.007 | 3.51 | 3.81 | 1.39 | 0.58 | 0.048 | 0.060 | 0.093 | 0.100 | ||
Gunashli | 0.038 | 0.031 | 0.016 | 0.004 | 3.62 | 4.18 | 1.10 | 0.40 | 0.046 | 0.048 | 0.056 | 0.067 | ||
4thFEFEWSN50 | 0.057 | 0.024 | 0.025 | 0.013 | 3.21 | 2.60 | 1.21 | 0.79 | 0.049 | 0.053 | 0.071 | 0.064 | ||
Dagdash | 0.040 | 0.032 | 0.021 | 0.008 | 3.18 | 2.86 | 1.25 | 0.72 | 0.043 | 0.043 | 0.057 | 0.075 | ||
Saratovskaya 29 | 0.037 | 0.013 | 0.017 | 0.005 | 3.19 | 1.80 | 1.24 | 0.56 | 0.052 | 0.048 | 0.065 | 0.063 | ||
strict difference between irrigated and rain-fed plants observed during booting stage. In some genotypes (Barakatli 95, Alinja 84, Tartar, Ruzi 84, Pirshahin1) there were big differences in LSM of irrigated and rain-fed plants during watery ripe stage.
Most genotypes of bread wheat formed more yield than genotypes of durum wheat under irrigated condition (
Water shortage led to a decrease in the Pn, gs and E, gm, WUE, an increase in Ci. Despite the fact that the gs, and E were relatively high during the watery ripe stage the Pn strongly suppressed. This fact indicates predominance of nonstomatal factors in regulation of Pn. Our previous results showed that gm is a dominant in regulation of Pn [
Water scarcity in the field led to adaptive changes in physiological traits of durum wheat and bread wheat genotypes. Reduction of gs results in a decrease of Pn and E, an increase of Ci. Close strict decrease in the RWC and Chl (a+b) content was observed in some genotypes under the influence of drought. Water shortage led to reduction of LA, dry mass and LAI which is strongly expressed during watery ripe stage. Different wheat genotypes have some advantages in agronomic, morphophysiological parameters, which can reduce the damage caused by water stress. Physiological studies on field grown wheat genotypes can be useful for identification of drought resistant genotypes.
Tofig I.Allahverdiyev, (2015) Physiological Traits of Durum Wheat (Triticum durum Desf.) and Bread Wheat (Triticum aestivum L.) Genotypes under Drought Stress. Agricultural Sciences,06,848-859. doi: 10.4236/as.2015.68082