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Ukrainian Journal of Ecology
Ukrainian Journal of Ecology, 2018, 8(4), 314-319
ORIGINAL ARTICLE
Assessment of drought resistance indices in spring bread wheat under various environmental conditions
S.B. Lepekhov1, L.P. Khlebova2
1 Altai Research Institute of Agriculture, Barnaul, Russia, E-mail: sergei.lepehov@yandex.ru 2Altai State University, pr. Lenina 61, Barnaul, 656049, Russia, E-mail: hlebova61@mail.ru Received: 18.10.2018. Accepted:25.11.2018
Drought stress is the most important factor limiting wheat yield in the Altai Territory, Russia. Several selection criteria have been proposed to select genotypes based on their performance in stressful and non-stressful environments. We tested seventy-five genotypes of spring bread wheat in a randomized complete block design with three replications for three years (2010-2012). The trials were conducted in the Altai Research Institute of Agriculture, Russia. Six drought resistance indices, including Sensitivity drought index (SDI), Mean productivity (MP), Tolerance index (To), Stress susceptibility index (SSI), Geometric mean productivity (GMP) and Stress tolerance index (ST) were calculated for each genotype based on grain yields under non-stress and three stress conditions. Stress intensity indices (SI) in the first, second, and third environments were low (SI= 0.39), moderate (SI= 0.56), and high (SI= 0.80), respectively. We found that different indices give a similar characteristic of the most drought-resistant and drought-susceptible genotypes. SSIfully corresponds to the SDIvalue, and STI corresponds to the GMP value (r = 1.00). Tolerance is closely related to SDI (r = 0.83-0.86). SDI and SSI are offered as useful indices for wheat breeding where stress is severe, while STI, MPand GMP are suggested if stress is less severe. Genotypes with high yield potential can be identified under moderate drought, but not under severe drought stress. Keywords: wheat; drought; resistance indices; grain yield
Drought is the most destructive abiotic stressor accompanying the entire history of agriculture. According to the time of onset and duration, drought may be short-term (at the beginning, middle or end of the growing season) and long-term (throughout the growing season), of varying degrees of intensity. This phenomenon is not just a shortage of water, but a complex combination of water deficiency, temperature stress, hot wind, soil salinity and other abiotic factors. Damage from it exceeds the damage from any other stressor. During 1967-1991, droughts affected 50 % of the 2.8 billion people who suffered from weather-related disasters (Kogan, 1997). Drought stress of varying degrees can be observed in almost all climatic zones (Passioura, 2007) and reduce wheat yields by up to 50 % (Reynolds et al., 2007) due to significant reductions in plant growth and shoot production (Ehdaie et al., 2008, 2012). In the Russian Federation, a particularly severe drought was in 2010 and 2012, which led in some regions to a complete or substantial loss of crop yields, including wheat. The peculiarity of the growing season in Siberia is the development of drought from the stage of germination through to flowering. The lack of moisture is often accompanied by high temperatures. Flowering and grain filling usually take place with a sufficient amount of precipitation.
An effective way to reduce damage from drought is to cultivate drought-resistant cultivars. But breeding for drought resistance is complicated by the lack of fast, reproducible screening techniques and the inability to routinely create defined and repeatable water stress conditions, when a large amount of genotypes can be efficiently evaluated (Ramirez & Kelly, 1998). Drought susceptibility of a genotype is often measured as a function of the reduction in yield under drought stress (Blum, 1988). In Russia, as a criterion for assessing drought tolerance of a cultivar, the value of the yield reduction in dry years to the yield of the cultivar in years with sufficient rainfall during the growing season is used (Litvinenko & Leshin, 1993). It coincides with the Sensitivity drought index (SDI) proposed by Farshadfar & Javadinia (2011 a). The genotypes with low value of this index will be more desirable.
Drought resistance in a broader agronomic sense is determined by the ability of a cultivar to produce the highest yield compared to other cultivars under drought conditions (K - grain yield under drought condition). Estimation by absolute yield and comparison of yield in dry and wet years, taken separately, do not provide an exhaustive picture of the practical drought tolerance of the cultivar and should be carried out in parallel (Kumakov, 1985). Currently, researchers seek a comprehensive assessment of the drought tolerance of cultivars using drought tolerance indices (Golabadi et al., 2006; Farshadfar & Sutka, 2003). Many authors studied the relationships of these indices with grain yield under stress and non-stress conditions. Aliakbari et al. (2013) found that tolerance Tol and MP indices appeared to be the most appropriate ones for screening drought tolerant genotypes. Sio-Se Mardeh et al. (2006) used drought tolerant indices in wheat and stated that under moderate stress, MP, GMP and STI were more effective in identifying high-yielding cultivars under both drought-stressed and
irrigated conditions. Under severe stress, none of the indices used were able to identify a group of high-yielding cultivars. They concluded that the effectiveness of selection indices in differentiating resistant cultivars varies with the stress severity. In the above and similar works, two backgrounds are used: irrigated and non-irrigated conditions. These experiments require the use of special techniques, are able to evaluate a small number of genotypes and do not fit well into the breeding process. In the works of Russian breeders to assess the adaptive properties of wheat, different years and agrotechnical options are used (sowing date, predecessor) (Ziborov, 2013). Given the distribution of precipitation in Siberia, which consists in a lack of moisture before flowering and excessive precipitation in the second half of the growing season, additional irrigation in the first half of the growing season will almost certainly cause lodging of all cultivars. In this regard, the arid conditions are modeled by growing wheat after the stubble predecessor. The aim of the study is to compare the selection criteria at different stress intensity to identify drought-tolerant wheat genotypes suitable for cultivation in arid zones of the Altai Territory, Russia.
Material and Methods
We studied 75 cultivars of spring bread wheat of various ecological and geographical origin and different ripening groups. The tests were carried out in the Altai Research Institute of Agriculture, The Altai Territory, Russia in 2010-2012. Cultivars were planted in a randomized complete block design with three replications. Sowing was carried out after fallow and cereal crop predecessor in the second decade of May. The size of the plot was 2 m2 (7 rows, 2 m long and 15 cm between rows). Drought tolerance indices were calculated using the following relationships:
SDI =
MP = ■
Y - Y )
yp
Y +Yp_ 2
Tol = Yp - Ys
(Farshadfar & Javadinia, 2011a) (1);
(Rosielle & Hamblin, 1981) (2);
(Rosielle & Hamblin, 1981) (3);
1 -Y
SSI =
1-
GMP = V Ys x Y Y x Y„
STI =
Y x Y
pm pm
(Fischer & Maurer, 1978) (4);
(Fernandez, 1992) (5);
(Fernandez, 1992) (6),
where Yp is grain yield of a cultivar under favorable conditions; Ys is grain yield of a cultivar under drought conditions; YSm and
Y
Ypm are the mean yields of all cultivars under stress and non-stress conditions, respectively, and 1--— is the stress
Ypm
intensity index (S/) (Ramirez-Vallejo & Kelly, 1998).
Tests with different levels of stress included: fallow predecessor 2010 (Yp) which is the favorable conditions, cereal crop predecessor 2011 ( Ysf) which is mild stress (S/= 0.39), fallow predecessor 2012 ( Y2) which is moderate stress (S/= 0.56), and cereal crop predecessor 2012 (Y3 which is severe stress (S/= 0.80). Meteorological data of the test location in 2010-2012 are shown in Tables 1 and 2.
Table 1. Monthly precipitation during the growing season 2010-2012, mm
Year May June July August The amount for the growing season
2010 18 45 120 13 195
2011 32 30 42 36 140
2012 24 10 97 44 175
Table 2. Average monthly air temperature during the growing season 2010-2012, °C
Year May June July August The average for the growing season
2010 10,2 18,6 17,5 17,6 16,0
2011 12,2 20,2 18,1 16,4 16,7
2012 12,1 22,1 22,1 18,4 18,7
The reliability of the differences among the mean values of a pair of genotypes was tested using the Least Significant Differences (LSD0,05). The results were statistically processed using the Microsoft Office Excel 2010 application software.
Results and Discussion
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Grain yield varied widely between environments and genotypes. The highest average yields (202-402 g m-2) were obtained in the Kp. They were lower in the YS1 and Y22 (138-236 g m-2 and 73-198 g m-2, respectively) and the lowest (31 -90 g m-2) in the K3. The average yields for all cultivars in the environments were 295 g m-2 (Yp), 181 g m-2 (Yn), 130 g m-2 (Y2), 60 g m-2 (Y3). The yield and drought tolerance indices of some genotypes are presented in Table 3. The indices evaluate different aspects of drought tolerance of cultivars, therefore full compliance between them, with rare exception, is not observed. Astana is characterized by the lowest yield in all environments, but according to SSI, Toland SDI, this sample should be recognized as drought-resistant. Saratovskaya 72 is characterized by similar values of drought tolerance indices, but, unlike Astana, this genotype has a rather high yield in arid conditions.
Table 3. Yield (g m-2) and tolerance indices of 10 contrast wheat cultivars (averaged over 2010-2012 years)
Genotype Yp Ys1 Ys2 Ys3 SSI STI Tol MP GMP SDI Ys*
Lutescens 697 360 230 182 88 0,92 0.69 193 263 241 0.54 167
Svetlanka 309 231 164 82 0.80 0.56 149 234 217 0.48 159
Lutescens 36/c 318 190 161 90 0.94 0.54 171 232 214 0.54 147
Saratovskaya 72 229 182 162 81 0.62 0.37 87 185 178 0.38 142
Lutescens 43/c 267 171 155 87 0.84 0.42 129 202 190 0.48 137
Lutescens 622 373 187 124 81 1.16 0.56 242 252 218 0.65 131
Lutescens 259 382 218 110 51 1.16 0.55 255 254 211 0.67 126
Astana 218 173 112 55 0.78 0.28 105 166 154 0.48 114
Tulajkovskaya 347 156 73 48 1.31 0.37 255 220 174 0.73 92
ostistaya
Altajskaya 325 320 163 87 41 1.22 0.36 223 208 170 0.70 97
LSD0,05 54 37 30 28 0.25 0.15 31 15 27 0.10 31
Note: * - Ys = Y + Ys2 + Yss)/3
In general, various indices give a similar characteristic to the three most drought-tolerant and drought-susceptible genotypes. In environments where the frequency of favorable years is high and droughts are not of an extreme nature, assessments related to the determination of average values of yield and the degree of its decline come to the fore. In environments where the frequency of drought occurrence is high enough, grain yield under drought condition is crucial, and all indicators based on the assessment of potential yield reduction should be used with caution, as the cultivar can have a low yield in favorable conditions, which will overstate SSI and SDI. Two cultivars with either high or low yield in both stress and non-stress environments may produce equal SSI. For this reason, selection based on this index, confuses the breeders (Mollasadeghi et al., 2001). In this case, there can be 4 variants of the reactions of cultivars in accordance with Fernandez (1992). These are high yields in all environments (Lutescens 697), significant grain productivity in favorable conditions and low grain productivity during drought (Lutescens 259, Lutescens 622, Tulaikovskaya ostistaya, Altajskaya 325), high Ys combined with a small Yp (Lutescens 43/c, Saratovskaya 72) and low yield in all environments (Astana).
To examine the relationship between drought tolerance indices, a correlation analysis was conducted in three environments with increasing drought stress (Tables 4, 5 and 6).
Table 4. Simple correlation coefficients of stress indices with grain yield of 75 wheat cultivars at Yp and YS1_
Yp SSI STI Tol MP GMP SDI Ys
Yp 1,00
SSI 0,76 1,00
STI 0,90 0,42 1,00
Tol 0,91 0,95 0,64 1,00
MP 0,95 0,55 0,99 0,75 1,00
GMP 0,91 0,44 1,00 0,65 0,99 1,00
SDI 0,76 1,00 0,42 0,95 0,55 0,44 1,00
Ys_045_-021_0,79_0,04_0,70_079_-021_1,00
Note: The critical value of the correlation coefficient is 0.22 (p = 0.05)
Identifying the relationship between Ys and Yp is important for the possibility of indirect selection of drought-resistant and productive genotypes in different conditions. Some studies have reported the absence of a positive correlation or a nonsignificant correlation between Ys and Yp (Sio-Se Mardeh et al., 2006; Zebarjadi et al., 2012; Yasir et al., 2013). Other studies have found a positive correlation between Ys and Yp (Farshadfar et al., 2012; Abdolshahi et al, 2013). This indicates that indirect selection for drought stress condition based on the result of normal condition would be efficient. In other hand, the high positive relationship between Ys and Yp indicates that the genotype x environment interaction in such an experiment is small, and in fact it is possible to avoid the irrigation option to assess drought tolerance.
According to our research, the correlation between yield in a favorable and arid environment was medium (r = 0.38-0.45) under mild and moderate stress. Under severe stress, correlation between Ysand Yp was non-significant.
Table 5. Simple correlation coefficients of stress indices with grain yield of 75 wheat cultivars at Yp and Ys2
Yp SSI ST/ Toi MP GMP SDI Ys
Yp 1,00
SSI 0,47 1,00
STI 0,77 -0,16 1,00
Toi 0,85 0,86 0,33 1,00
MP 0,93 0,11 0,95 0,59 1,00
GMP 0,78 -0,16 1,00 0,34 0,96 1,00
SDI 0,47 1,00 -0,16 0,86 0,11 -0,16 1,00
Y_0,38_-0,62_087_-0,16_070_0,87_-0,62_1,00
Abdolshahi et al. (2013) pointed out that the application of all drought-tolerant/susceptible indices simultaneously is a good approach for screening drought-tolerant genotypes. However, the results of our study suggest that SSI coincides with SDI, and STI coincides with GMP. Fernandez (1992) stated that STI is estimated based on GMP and thus the rank correlation between STI and GMP is equal to 1. Tol is closely associated with SSI, therefore it is also associated with SDI (r = 0.83-0.95) in three levels of stress. GMP and MP, and therefore STI, give a close assessment of the cultivars in mild and moderate drought. Therefore, the simultaneous calculation of these indices can be avoided so as not to clutter the study. Similar results were reported by Dadbakhsh et al. (2011) and Sareen et al. (2014).
Table 6. Simple correlations coefficients of stress indices with grain yield of 75 wheat cultivars at Yp and Ys3_
Yp SSI STI Toi MP GMP SDI Ys
Yp 1,00
SSI 0,65 1,00
STI 0,44 -0,35 1,00
Toi 0,96 0,83 0,19 1,00
MP 0,96 0,40 0,68 0,84 1,00
GMP 0,45 -0,36 1,00 0,19 0,69 1,00
SDI 0,65 1,00 -0,35 0,83 0,40 -0,36 1,00
Ys -0,15 -0,83 0,81 -0,41 0,14 0,81 -0,83 1,00
To be of practical value, any drought index must show consistent results over different environments (Mohammadi, 2016). Fernandez (1992) believes that the optimal selection criterion should separate high-yielding genotypes from all other cultivars in arid and favorable conditions. He concluded that MP, SSI and Tol were not able to identify such genotypes, and STI was more suitable. Geravandia et al. (2011) came to a similar conclusion. Saba et al. (2001) found that narrow-sense heritability estimates were very low for SSI and Tol, but moderate for GMP, MP and STI. Thus, selection based on the latter indices could be more promising than on SSIand Tol. STI is a suitable yield-based drought resistance index that can be employed in plant breeding programs because of its high narrow-sense heritability and the inherent ability of selecting high-yielding genotypes in either stressed or non-stressed conditions (Farshadfar et al., 2011b). Abdoli & Saeidi (2012) and Mohammadi et al. (2011) concluded that STI, GMPand MPindices were appropriate indicators for identification of cultivars with high grain yield in both water deficiency and control treatments.
Significant relationships were observed between Ys and STI, GMP, MP in all three years, indicating that the selection of genotypes for these indices will improve the yield under stress (Farshadfar et al., 2012). At the same time, Zebarjadi et al. (2012) reported that the correlation of MP with Ys was not significant. We note that MP is not able to identify resistant genotypes only under severe stress, where Ys and Yp do not correlate with each other.
Correlation analysis showed that STI was positively correlated with grain yield under both conditions in all three years. Although with severe drought, the correlation between STI and Yp decreases to a medium level (r = 0.44). Therefore, in such conditions, the STI is no longer a suitable index. SSI is more suitable. This result has been confirmed by other studies (Bayoumi et al., 2008; Akgura et al., 2011), but SSI should be used along with yield data under stress (Najaphy et al., 2011). No significant correlation was found between SSI and yield under mild stress conditions showing that SSI will not discriminate drought sensitive cultivars under such conditions. Ehdaie et al. (1996) also indicated that SSIis not able to identify potentially productive genotypes.
Yasir et al. (2013) noted that the genotypes with high values of Tol and SSI were able to produce high yield only in the non-stressed environment. Tol assesses the absolute difference in yield of a cultivar under favorable and arid conditions. This difference can be regarded as a decrease in yield under drought and as an increase in yield under favorable conditions in relation to the environment with a moisture deficit. Correlation analysis showed that Tol was closely related to Yp, therefore, potentially productive cultivars significantly reduced grain productivity under drought. Farshadfar et al. (2014) found that no significant correlation was observed between Ys and Tol. In our study, Ys is weakly associated with Tol under moderate drought (Tables 4 and 5), which indicates the possibility selecting potentially productive cultivars under such conditions. A significant negative correlation coefficient between Ys and Tol (Table 6) indicates that a high yield of a cultivar under severe drought conditions is associated with a low yield potential. Blum (1996) came to a similar conclusion.
Under severe drought conditions, GMP is more closely associated with Ys compared to MP. The identification of drought-tolerant and potentially highly productive genotypes significantly depends on the conditions in which they are assessed.
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Under the most severe drought, such criteria are SSI and SDI (Table 6), while under droughts of lower intensity they are STI, MP and GMP (Tables 4 and 5). In the transition from low-productive to high-productive environments, the correlation coefficient between GMPand SDIchanges its sign to the opposite one, and the correlation between SDI and Yschanges from a significant negative to an insignificant. Thus, the breeders should choose the indices on the basis of stress severity in the target environment (Akgura et al., 2011).
Conclusions
SSI fully corresponds to the value of SDI, and STI is fully consistent with the value of GMP. Therefore these indicators should not be used together to characterize genotypes. Under the most severe drought, the criteria for identifying drought-tolerant and simultaneously high yielding genotypes are SSI and SDI. Under drought of lower intensity, they are STI, MP and GMP. Genotypes with a high yield potential can be identified under moderate drought conditions, but cannot be identified under severe stress.
Conflict of interest
The authors declare that they have no conflict of interests.
References
Abdoli, M., & Saeidi, M. (2012). Using different indices for selection of resistant wheat cultivars to post anthesis water deficit in the west of Iran. Annals of Biological Research, 3(3), 1322-1333.
Abdolshahi, R., Safarian, A., Nazari, M., Pourseyedi, S., & Mohamadi-Nejad, G. (2013). Screening drought-tolerant genotypes in bread wheat (Triticum aestivum L.) using different multivariate methods. Archives of Agronomy and Soil Science, 59(5), 685704.
Akgura, M., Partigog, F., & Kaya, Y. (2011). Evaluating of drought stress tolerance based on selection indices in turkish bread wheat landraces. The Journal of Animal & Plant Sciences, 21(4), 700-709.
Aliakbari, M., Saed-Moucheshi, A., Hasheminasab, H., Pirasteh-Anosheh, H., Asad, M.T., & Emam, Y. (2013). Suitable stress indices for screening resistant wheat genotypes under water deficit conditions. International Journal of Agronomy and Plant Production, 4(10), 2665-2672.
Bayoumi, T.Y., Eid, M.H., & Metwali, E.M. (2008). Application of physiological and biochemical indices as a screening technique for drought tolerance in wheat genotypes. African Journal of Biotechnology, 7(14), 2341 -2352. Blum, A. (1988). Plant Breeding for Stress Environments. Florida: CRC Press, 212.
Blum, A. (1996). Yield potential and drought resistance: are they mutually exclusive? In: Reynolds M.P., Rajaram S., Mc Nab A. (Eds.), Increasing Yield Potential in Wheat: Breaking the Barriers. Proceedings of a Workshop Held in Ciudad Obregon, Sonora, Mexico.
Dadbakhsh, A., Yazdansepas, A., & Ahmadizadeh, M. (2011). Study drought stress on yield of wheat (Triticum aestivum L.) genotypes by drought tolerance indices. Advances in Environmental Biology, 5(7), 1804-1810.
Ehdaie, B., & Shakiba, M.R. (1996). Relationship of internode-specific weight and water-soluble carbohydrates in wheat. Cereal Research Communication, 24, 61 -67.
Ehdaie, B., Alloush, G.A., & Waines, J.G. (2008). Genotypic variation in linear rate of grain growth and contribution of stem reserves to grain yield in wheat. Field Crops Research, 106, 34-43. doi: 10.1016/j.fcr.2007.10.012
Ehdaie, B., Layne, A.P., & Waines, J.G. (2012). Root system plasticity to drought influences grain yield in bread wheat. Euphytica, 186, 219-232. doi: 10.1007/s10681 -011 -0585-9
Farshadfar, E., & Javadinia, J. (2011a). Evaluation of Chickpea (Cicer arietinum L.) genotypes for drought tolerance. Seed and Plant Improvement Journal, 27(4), 517-537 (in Persian).
Farshadfar, E., & Sutka, J. (2003). Multivariate analysis of drought tolerance in wheat substitution lines. Cereal Research Communications, 31(1/2), 33-40.
Farshadfar, E., Poursiahbidi, M.M., & Abooghadareh, A.R.P. (2012). Repeatability of drought tolerance indices in bread wheat genotypes. International Journal of Agriculture and Crop Sciences, 4(13), 891 -903.
Farshadfar, E., Rasoli, V., Teixeira da Silva, J.A., & Farshadfar M. (2011b). Inheritance of drought tolerance indicators in bread wheat (Triticum aestivum L.) using a diallel technique. Australian Journal of Crop Science, 5(7), 870-878. Farshadfar, E., Sheibanirad, A., & Soltanian, M. (2014). Screening landraces of bread wheat genotypes for drought tolerance in the field and laboratory. International Journal of Farming & Allied Sciences, 3(3), 304-311.
Fernandez, G.C.J. (1992). Effective selection criteria for assessing plant stress tolerance. In: Kuo, C.G. (Ed.), Adaptation of Food Crops to Temperature and Water Stress Tolerance. Proc. of an Internat. Symp. Taiwan: Asian Vegetable Research and Development Center.
Fischer, R.A., & Maurer R. (1978). Drought resistance in spring wheat cultivars. I. Grain yield responses. Australian Journal of Agricultural Research, 29, 897-917.
Geravandia, M., Farshadfar, E., & Kahrizia, D. (2011). Evaluation of some physiological traits as indicators of drought tolerance in bread wheat genotypes. Russian Journal of Plant Physiology, 58 (1), 69-75.
Golabadi, M., Arzani A., & Maibody Mirmohammadi, M.S.A. (2006). Assessment of drought tolerance in segregating populations in durum wheat. African Journal of Agricultural Research, 1(5), 162-171.
Kogan, F.N. (1997). Global drought watch from space. Bulletin of the American Meteorological Society, 78, 621 -636. Kumakov, V.A. (1985). Fiziologicheskoe obosnovanie modelej sortov pshenicy. M.: Agropromizdat. (In Russian) Litvinenko, N.A., & Leshin, V.N. (1993). Biologicheskie aspekty selekcii ozimoj myagkoj pshenicy na zasuhoustojchivost' v usloviyah stepnoj zony. Sel'skohozyajstvennaya biologiya, 5, 63-70. (In Russian)
Mohammadi, M., Karimizadeh, R., & Abdipour, M. (2011). Evaluation of drought tolerance in bread wheat genotypes under dryland and supplemental irrigation condition. Australian Journal of Crop Science, 5(4), 487-493.
Mohammadi, R. (2016). Efficiency of yield-based drought tolerance indices to identify tolerant genotypes in durum wheat. Euphytica, 211, 71. doi:10.1007/s10681 -016-1727-x
Mollasadeghi, V., Valizadeh, M., Shahryari, R., & Imani, A.A. (2001 ). Evaluation of drought tolerance of bread wheat genotypes using stress tolerance indices at presence of potassium humate. American-Eurasian Journal of Agricultural & Environmental Sciences, 10(2), 151 -156.
Najaphy, A., & Geravandi, M. (2011). Assessment of indices to identify wheat genotypes adapted to irrigated and rain-fed environments. Advances in Environmental Biology, 5(10), 3212-3218.
Passioura, J. (2007). The drought environment: physical, biological and agricultural perspectives. Journal of Experimental Botany, 58(2), 113-117. doi: https://doi.org/10.1093/jxb/erl212
Ramirez-Vallejo, P., & Kelly, J.D. (1998). Traits related to drought resistance in common bean. Euphytica, 99, 2, 127-136. doi:10.1023/A:1018353200015
Rosielle, A.A., & Hamblin, J. (1981). Theoretical aspects of selection for yield in stress and non-stress environments. Crop Science, 21, 943-946.
Saba, J., Moghaddam, M., Ghassemi K., & Nishabouri M.R. (2001). Genetic properties of drought resistance indices. Journal of Agricultural Science Technology, 3, 43-49.
Sareen, S., Tyagi, B.S., Sarial, A.K., Tiwari, V., & Sharma, I. (2014). Trait analysis, diversity, and genotype x environment interaction in some wheat landraces evaluated under drought and heat stress conditions. Chilean Journal of Agricultural Research, 74, 2, 135-142.
Sio-Se Mardeh, A., Ahmadi, A., Poustini, K., & Mohammadi, V. (2006). Evaluation of drought resistance indices under various environmental conditions. Field Crops Research, 98, 222-229. doi:10.1016/j.fcr.2006.02.001
Yasir, T.A., Chen, X., Tian, L., Condon, A.G., & Hu, Y.-G. (2013). Screening of Chinese bread wheat genotypes under two water regimes by various drought tolerance indices. Australian Journal of Crop Science, 7(13), 2005-2013.
Zebarjadi, A., Mirany, T., Kahrizi D., Ghobadi, M., & Nikoseresht, R. (2012). Assessment of drought tolerance in some bread wheat genotypes using drought resistance indices. Biharean biologist, 6(2), 94-98.
Ziborov, A.I. (2013). Ocenka ehkologicheskojplastichnosti sovremennyh sortov iperspektivnyh linij yarovoj tverdojpshenicy v usloviyah Priobskoj lesostepi Altajskogo kraya: dis. kand. sel'skohozyajstvennyh nauk, Tyumen': Gosudarstvennyj agrarnyj universitet Severnogo Zaural'ya. (In Russian)
Citation:
Lepekhov, S.B., Khlebova, L.P. (2018). Assessment of drought resistance indices in spring bread wheat under various environmental conditions. Ukrainian Journal of Ecology, 8( 4), 314-319. I '.■ ■ ■ E^^MIThis work is licensed under a Creative Commons Attribution 4.0. License
