The experiment was conducted with thirty-five wheat genotypes at the research field of the Department of Agronomy of the Bangabandhu Sheikh Mujibur Rahman Agricultural University from November 2011 to March 2012 to screen out the wheat genotypes for drought tolerance of thirty-five wheat genotypes under water deficit condition. The experiment was carried out in a split-plot design comprising two water regimes in main plot and thirty-five wheat genotypes were placed randomly in sub-plot with three replications. From this experiment, it was found that water deficit condition severely reduced the plant height, number of effective tillers m ﹣2 , spike length, number of spikelets spike ﹣1 , number of grains spike ﹣1 and thousand grain weight. Based on the percentage of yield reduction, the genotypes BARI Wheat 26, Sourav, BAW 1169 and BAW 1158 were categorized in tolerant group exhibited low yield reduction (>30%) and the genotypes Seri, Pavon, BAW 1166, BAW 1167, BAW 1171 and BAW 1173 were ranked in susceptible group due to very low yielding ability with high yield reduction which ranged from 50.01% to 59.17% in water deficit condition. The maximum increased canopy temperature was recorded in the genotypes BAW 1166, BAW 1167, Seri, Pavon and BARI Wheat 25. The minimum was in the genotypes BARI Wheat 26, BAW 1157, Sourav, BAW 1169 and Gourab. The highest MP, GMP and STI values were recorded in the genotypes BARI Wheat 26, BAW 1158, Sourav, BAW 1169 and BAW 1170. Our results revealed that BARI Wheat 26, BAW 1158, Sourav, BAW 1169 and BAW 1170 were more capable to tolerate water deficit condition.
Wheat, next to rice is the staple food of the people in Bangladesh grown over an area of 3.74 million hectares with an annual production of about 1 million metric tons with an average of 2.60 t・ha−1 [
Canopy temperature is related to plant water stress because the evaporative cooling involved in transpiration may cool leaves below ambient air temperature. If soil water is limiting, plant water stress develops, transpiration decreases and the canopy temperature rises. Plants with adequate supply of water maintained their canopy temperature below the air temperature, whereas the plants with inadequate supply of water exhibited their canopy temperature above the air temperature [
Selecting wheat genotypes that could tolerate drought stress and produce acceptable yield has been the major challenge for the wheat breeders in the past 50 years [
The experiment was carried out at the research field of the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Salna, Gazipur from November, 2011 to March, 2012 on an upland soil. It is located at the center of Madhupur Tract (24˚05' North latitude and 90˚16' East longitude) at an elevation of 8.4 m above the sea level. The soil of the experimental field belongs to Salna series of Shallow Red-Brown Terrace soil type (AEZ 28) with silty clay texture in surface and silty clay loam in sub-surface region of the soil [
Thirty-five wheat genotypes including most of the popular varieties, some advanced lines and some lines from abroad collected from Wheat Research Centre of Bangladesh Agricultural Research Institute, Nashipur, Dinajpur, Bangladesh were used in the present study.
The land was well prepared by ploughing and cross-ploughing four times with a power tiller. Laddering was done for breaking the clods and leveling the lands. The various stubbles were removed by hand from the experiment field just before preparing the plot. The individual plots were prepared by making ridges (8 - 10 cm high) around the each plot to restrict the lateral run off of fertilizer with irrigation water.
The experiment was carried out in a split-plot design comprising two water regimes in main plot and 35 wheat genotypes were placed randomly in sub-plot with three replications. The water regimes were 1) Control (four irrigations were applied at crown root initiation, booting, anthesis and grain filling stages), and 2) Water deficit stress (irrigation was stopped after crown root initiation stage i.e. 20 days after sowing and the crop was protected from rainfall by rainout shelter). Thirty-five wheat genotypes including most of the popular varieties and some advanced lines collected from Wheat Research Centre (WRC) of Bangladesh Agricultural Research Institute (BARI), Dinajpur were Prodip, Shatabdi, Sourav, Gourab, Sufi, Kanchan, Seri, Pavon, Barkat, Balaka, Aghrani, Akbar, BARI Wheat 26, Protiva, Ananda, Bijoy, BARI Wheat 25, BAW 1151, BAW 1157, BAW 1158, BAW 1159, BAW 1160, BAW 1161, BAW 1162, BAW 1163, BAW 1164, BAW 1165, BAW 1166, BAW 1167, BAW 1168, BAW 1169, BAW 1170, BAW 1171, BAW 1172 and BAW 1173. The unit plot size was consisted of 6 rows each of 2.5 m long having a row to row distance of 20 cm.
Wheat seeds at the rate of 120 kg・ha−1 were sown in line by hand on November 24, 2011. Seeds were placed continuously in lines by making narrow and shallow furrows with iron rod and covered with soil by hand. After sowing of seeds light irrigation was given to ensure uniform germination of seeds. Fertilizers were applied @ 100-60-40-20-1 kg・ha−1 N-P2O5-K2O-S in the form of urea, triple super phosphate, muriate of potash and gypsum, respectively. Two-third of urea and total amount of other fertilizers were applied during final land preparation. The rest amount of urea was top dressed at crown root initiation stage (20 days after sowing) followed by first irrigation. Intercultural operations were done uniformly in each plot to ensure normal growth of the crop. Weeding and mulching were done simultaneously in the experimental plot for two times, firstly at 15 days after sowing (DAS) and secondly, at 35 DAS. Thinning was also done at 14 DAS.
Canopy temperature was measured with an infrared thermometer (Model THI-500, TASCO, Japan) at 12:30 pm on the day. The thermometer was held so that the sensor viewed only the canopy at an oblique angle above the horizontal; this position gave an elliptical canopy target [
Stress tolerance and susceptibility indices including relative performance (RP), mean productivity (MP), geometric mean productivity (GMP), tolerance (TOL), stress susceptibility index (DSI), stress tolerance index (STI), and yield stability index (YSI) for water deficit environment were calculated based on grain yield under water deficit stress and control conditions. Stress tolerance attributes were calculated by the following formulae:
Mean productivity (MP) and Tolerance (TOL) was calculated according to Gupta et al., [
Geometric mean productivity (GMP), stress tolerance index (STI) and stress susceptibility index (SSI) were calculated according to Fernandez [
where,
Yws = mean yields of a given genotype in water stress (WS) conditions;
Yns = mean yields of a given genotype in non-stress (NS) conditions and;
Xns = mean of all genotypes under non-stress (NS) condition.
where,
Yws = mean yields of a given genotype in WS condition;
Yns = mean yields of a given genotype in NS condition;
DII = Drought intensity index.
The drought intensity index (DII) for each water regime was calculated as
where,
Xws = mean of all genotypes under WS condition;
Xns = mean of all genotypes under NS conditions.
where,
Yws = mean yields of a given genotype in WS condition;
Yns = mean yields of a given genotype in NS condition.
Recorded data were analyzed by statistically using the software MSTATC (Developed by the Department of Crop and Soil Sciences, Michigan State University, East Lansing, MI 48824 USA). Significance between treatments were tested by using least significant difference test (LSD) at p < 0.05 level.
The means and the ranges of relative value of ten characters of the 35 wheat genotypes subjected to water deficits are given in
Relative value of number of tillers, spike length, grains spike−1, 1000 grain weight, grain yield and straw yield of thirty-five wheat genotypes are presented in
Plant characters | Range | Mean ± SD |
---|---|---|
Plant height | 0.82 - 0.93 | 0.88 ± 0.03 |
Tiller plant−1 | 0.42 - 0.73 | 0.58 ± 0.07 |
Flag leaf length | 0.71 - 1.00 | 0.87 ± 0.06 |
Spike length | 0.84 - 0.96 | 0.90 ± 0.03 |
Spikelets spike−1 | 0.70 - 0.94 | 0.81 ± 0.04 |
Grains spike−1 | 0.75 - 0.91 | 0.83 ± 0.04 |
1000 grain weight | 0.79 - 0.92 | 0.84 ± 0.04 |
Grain yield | 0.41 - 0.91 | 0.59 ± 0.10 |
Straw yield | 0.50 - 0.83 | 0.64 ± 0.08 |
Harvest index | 0.85 - 1.14 | 0.95 ± 0.06 |
Akram [
Thirty-five wheat genotypes were ranked on the basis of their yield reduction due to water deficit over control (
Group | Yield reduction over control (%) | Genotypes |
---|---|---|
Tolerant | Less than 30.00 | BARI Wheat 26, Sourav, BAW 1169 and BAW 1158 |
Moderately tolerant | 30.01 - 40.00 | BAW 1151, BAW 1157, BAW 1159, BAW 1161, BAW 1165 and BAW 1170 |
Moderately susceptible | 40.01 - 50.00 | Prodip, Shatabdi, Gourav, Sufi, Kanchan, Barkat, Balaka, Aghrani, Akbar, Protiva, Ananda, Bijoy, BARI Wheat 25, BAW 1160, BAW 1162, BAW 1163, BAW 1164, BAW 1168 and BAW 1172 |
Susceptible | Above 50.01 | Seri, Pavon, BAW 1166, BAW 1167, BAW 1171 and BAW 1173 |
Tolerant | Less than 30.00 | BARI Wheat 26, Sourav, BAW 1169 and BAW 1158 |
Canopy temperature measured at anthesis stage varied significantly among the genotypes due to water deficit presented in
The different stress tolerance indices used in this experiment are presented in
Genotypes | Yp | Ys | MP | TOL | GMP | STI | YSI | SSI |
---|---|---|---|---|---|---|---|---|
Prodip | 5.06 | 3.00 | 4.03 | 2.06 | 3.89 | 0.54 | 0.59 | 1.00 |
Shatabdi | 4.82 | 2.85 | 3.84 | 1.98 | 3.71 | 0.49 | 0.59 | 1.01 |
Sourav | 4.81 | 3.59 | 4.20 | 1.22 | 4.16 | 0.61 | 0.75 | 0.62 |
Gourab | 5.63 | 3.20 | 4.42 | 2.44 | 4.24 | 0.64 | 0.57 | 1.07 |
Sufi | 5.78 | 3.39 | 4.59 | 2.38 | 4.43 | 0.70 | 0.59 | 1.02 |
Kanchan | 5.79 | 3.10 | 4.45 | 2.70 | 4.24 | 0.64 | 0.53 | 1.15 |
Seri | 4.34 | 1.94 | 3.14 | 2.40 | 2.90 | 0.30 | 0.45 | 1.37 |
Pavon | 4.11 | 1.68 | 2.89 | 2.43 | 2.62 | 0.24 | 0.41 | 1.46 |
Barkat | 5.81 | 3.36 | 4.58 | 2.45 | 4.42 | 0.69 | 0.58 | 1.04 |
Balaka | 4.49 | 2.66 | 3.58 | 1.84 | 3.46 | 0.42 | 0.59 | 1.01 |
Aghrani | 5.14 | 3.00 | 4.07 | 2.14 | 3.92 | 0.55 | 0.58 | 1.03 |
Akbar | 5.72 | 3.32 | 4.52 | 2.40 | 4.36 | 0.67 | 0.58 | 1.03 |
BARI Wheat 26 | 5.48 | 4.98 | 5.23 | 0.50 | 5.22 | 0.97 | 0.91 | 0.22 |
Protiva | 5.60 | 3.15 | 4.38 | 2.46 | 4.20 | 0.63 | 0.56 | 1.08 |
Ananda | 5.47 | 2.98 | 4.23 | 2.49 | 4.04 | 0.58 | 0.54 | 1.13 |
Bijoy | 5.06 | 3.00 | 4.03 | 2.05 | 3.90 | 0.54 | 0.59 | 1.00 |
BARI Wheat 25 | 4.80 | 2.28 | 3.54 | 2.51 | 3.31 | 0.39 | 0.48 | 1.29 |
BAW 1151 | 4.58 | 2.82 | 3.70 | 1.76 | 3.59 | 0.46 | 0.62 | 0.95 |
BAW 1157 | 5.81 | 3.58 | 4.70 | 2.22 | 4.56 | 0.74 | 0.62 | 0.95 |
BAW 1158 | 5.79 | 4.55 | 5.17 | 1.25 | 5.13 | 0.93 | 0.78 | 0.53 |
BAW 1159 | 5.60 | 3.52 | 4.56 | 2.08 | 4.44 | 0.70 | 0.63 | 0.92 |
BAW 1160 | 4.96 | 2.89 | 3.93 | 2.07 | 3.79 | 0.51 | 0.58 | 1.03 |
BAW 1161 | 5.74 | 3.53 | 4.64 | 2.21 | 4.50 | 0.72 | 0.61 | 0.95 |
BAW 1162 | 5.52 | 3.10 | 4.31 | 2.43 | 4.14 | 0.61 | 0.56 | 1.08 |
BAW 1163 | 5.60 | 3.26 | 4.43 | 2.34 | 4.27 | 0.65 | 0.58 | 1.03 |
BAW 1164 | 5.49 | 3.21 | 4.35 | 2.28 | 4.20 | 0.63 | 0.58 | 1.03 |
BAW 1165 | 5.57 | 3.72 | 4.65 | 1.84 | 4.55 | 0.74 | 0.67 | 0.82 |
BAW 1166 | 5.45 | 2.43 | 3.94 | 3.02 | 3.64 | 0.47 | 0.45 | 1.37 |
BAW 1167 | 4.98 | 2.18 | 3.58 | 2.80 | 3.29 | 0.38 | 0.44 | 1.39 |
BAW 1168 | 5.13 | 3.26 | 4.20 | 1.87 | 4.09 | 0.59 | 0.64 | 0.90 |
BAW 1169 | 5.81 | 4.24 | 5.03 | 1.57 | 4.96 | 0.87 | 0.73 | 0.67 |
BAW 1170 | 5.73 | 4.00 | 4.87 | 1.73 | 4.79 | 0.81 | 0.70 | 0.75 |
BAW 1171 | 5.69 | 2.65 | 4.17 | 3.04 | 3.88 | 0.54 | 0.47 | 1.32 |
BAW 1172 | 4.96 | 3.19 | 4.08 | 1.77 | 3.98 | 0.56 | 0.64 | 0.88 |
BAW 1173 | 5.76 | 2.70 | 4.23 | 3.06 | 3.95 | 0.55 | 0.47 | 1.31 |
Mean | 5.32 | 3.15 | ||||||
LSD (0.05) | 0.47 |
Yp = Control yield, Ys = Water deficit yield, MP = Mean productivity, TOL = Tolerance, GMP = Geometric mean productivity, STI = Stress tolerance index, YSI = Yield stability index, SSI = Stress susceptibility index.
Yp | Ys | MP | TOL | GMP | STI | YSI | SSI | |
---|---|---|---|---|---|---|---|---|
Yp | 1.00 | |||||||
Ys | 0.62** | 1.00 | ||||||
MP | 0.86** | 0.93** | 1.00 | |||||
TOL | 0.12 | −0.71** | −0.40* | 1.00 | ||||
GMP | 0.81** | 0.96** | 0.99** | −0.49** | 1.00 | |||
STI | 0.78** | 0.97** | 0.99** | −0.53** | 0.99** | 1.00 | ||
YSI | 0.28 | 0.92** | 0.73** | −0.92** | 0.79** | 0.81** | 1.00 | |
SSI | −0.28 | −0.92** | −0.73** | 0.92** | −0.79** | −0.81** | −1.00** | 1.00 |
Yp = Control yield, Ys = Water deficit yield, MP = Mean productivity, TOL = Tolerance, GMP = Geometric mean productivity, STI = Stress tolerance index, YSI = Yield stability index, SSI = Stress susceptibility index, **Indicates correlation is significant at the 0.01 level, *Correlation is significant at the 0.05 level.
that a small value of TOL is desirable, selection for this parameter would tend to favor low yielding genotypes. A larger value of TOL and SSI show relatively more sensitivity to water deficit, thus a smaller values of TOL and SSI are favored. Several authors noticed that selection based on these two indices favors genotypes with low yield under non-stress conditions and high yield under stress conditions [
The present study indicated that there was a positive and significant correlation among MP, GMP, STI and yield under both water deficit and control conditions and hence they were better predictors than TOL, SSI and YSI (
Water deficit condition severely reduced the plant height, number of effective tillers m−2, spike length, number of spikelets spike−1, number of grains spike−1 and TGW. Based on the percentage of yield reduction the genotypes BARI Wheat 26, Sourav, BAW 1169 and BAW 1158 were categorized in tolerant group because they exhibited low yield reduction (>30%) and the genotypes Seri, Pavon, BAW 1166, BAW 1167, BAW 1171 and BAW 1173 were ranked in susceptible group due to their very low yielding ability and very high yield reduction which ranged from 50.01 to 59.17% in water deficit condition. The highest increase in canopy temperature (25%) was recorded in the genotype BAW 1166, and it was close to that in BAW 1167 (24%), Seri (23%), Pavon (21%) and BARI Wheat 25 (21%). The lowest increase in canopy temperature was recorded in BARI Wheat 26 (6%) which was followed by those in BAW 1157 (8%), Sourav (8%), BAW 1169 (9%) and Gourab (9%). The maximum values for MP, GMP and STI were noted in the genotypes BARI Wheat 26, BAW 1158, Sourav, BAW 1169 and BAW 1170. So, on the basis of canopy temperature, yield and drought tolerant indices for selecting the wheat genotypes for water deficit environment, BARI Wheat 26, BAW 1158, Sourav, BAW 1169 and BAW 1170 may be considered.
Wheat genotypes showed wide range of genetic variability in water deficit tolerance which could be considered as a potential source of breeding material. The genotypes BARI Wheat 26, BAW 1158, Sourav, BAW 1169 and BAW 1170, could be considered as relatively water deficit tolerant. Different physiological and biochemical indicators of water deficit tolerance could be studied for final conclusion. Finally, Multi-location/adaptive trials in severe drought prone areas may be carried out to confirm their performances.
Appreciation is extended to Director General of Bangladesh Agricultural Research Institute for permission to pursue higher studies leading to Ph.D. with scholarship and allowing leave on deputation. I also would like to express my whole hearted gratefulness and appreciation to the Department of Agronomy, Bangabandhu Skeikh Mujibur Rahman Agricultural University Gazipur for providing facilities of this study.
Md. Mahfuz Bazzaz,Qazi Abdul Khaliq,Md. Abdul Karim,Abdullah Al-Mahmud,Md. Shawquat Ali Khan, (2015) Canopy Temperature and Yield Based Selection of Wheat Genotypes for Water Deficit Environment. Open Access Library Journal,02,1-11. doi: 10.4236/oalib.1101917