Showing 72 results for Drought
Hooman Razi, Mohammad Taghi Assad,
Volume 2, Issue 1 (4-1998)
Abstract
Two field experiments were conducted in 1996 at the experimental station, College of Agriculture, Shiraz University at Badjgah. Fourteen cultivars consisting of eight hybrids and six open pollinated cultivars were grown in two randomized complete block designs with four replications.
The well-watered experiment received water when evaporation reached 65±5 mm from class A evaporation pan.
The water-limited experiment was irrigated in terms of 125±5mm evaporation from class A evaporation pan. Days to flowering, days to physiological maturity, head diameter, stem diameter, number of leaves per plant, plant height, number of filled seeds per head, 1000 seed weight, kernel percentage, unfilled seed percentage, seed yield, oil percentage, oil yield and harvest index were measured.
Most of the traits including seed yield and oil yield showed considerable genotypic and phenotypic variations. Highly significant differences were observed among cultivars. In normal and water stress conditions, the highest seed yield were obtained by Louc and Armavirsky cultivars, respectively. Water stress significantly decreased yield and its components. Furthermore, days to physiological maturity reduced in response to water deficit. However, oil percentage did not differ significantly. Drought resistance indexes were calculated in order to evaluate the response of each cultivar to water deficit. No association was found between yield potential and the stress susceptibility index, suggesting that drought resistance and high yield potential may be combined to improve sunflower cultivars. In addition, it was revealed that selection for height mean productivity and stress tolerance index will improve yield and drought tolerance simultaneously. Among cultivars that were used in this study, Armavirsky, besides having a relatively higher yield, was also drought tolerant.
V. Karimi, A.a. Kamkar-Haghighi, A.r. Sepaskhah, D. Khalili,
Volume 5, Issue 4 (1-2002)
Abstract
Drought can occur at such times when variables such as rainfall depth, run-off, soil moisture, etc. show a deficiency, or variables such as temperature show an increase, or when ground water level shows a decrease in comparison with the average level. Therefore, drought can be evaluated with respect to agricultural, meteorological, or hydrological variability. In this research, considering the meteorological aspects, the method by Herbst et al., later modified by Mohan and Rangacharia, was applied in drought evaluation in Fars Province, Iran. Monthly rainfall measurements over a period of 21 years for 51 stations obtained from Fars Regional Water Board, were used in the analysis. Maps showing lines of iso-duration and iso-intensity lines were developed for the province. Based on the results, northeast, southeast, south, and southwestern parts of the province have the highest potential for being affected by drought events.
M. J. Arvin, N. Kazemi-Pour,
Volume 5, Issue 4 (1-2002)
Abstract
A glasshouse study was conducted to measure the effects of salinity and drought stresses on growth and chemical and biochemical composition of 4 onion cultivars. The cultivars were Dessex, Texas Early Grano (Texas), Dehydrator, and PX492. Salinity treatments included control, 45mM NaCl, 45mM NaCl + 5mM CaCl2 and drought treatments were control (maintaining soil moisture at field capacity) and irrigation when 50% of available water was used. Four weeks after the treatments, the plants were harvested and root and shoot dry weights (RDW, SDW), Na+, K+, Ca2+, total protein, reduced sugars, as well as free proline contents were measured in both roots and shoots.
Results showed that NaCl and drought treatments significantly reduced SDW and RDW. The Texas cultivar and the Dessex cultivar produced the highest and the lowest amounts of SDW, respectively. NaCl significantly increased Na+ uptake but reduced K+ uptake in shoots and roots and also reduced Ca2+ uptake in roots. NaCl+CaCl2 significantly alleviated the deleterious effects of NaCl such that SDW significantly increased in two cultivars and increased RDW and the K+ contents while causing decreased Na+ and sugar contents in shoots and roots of all cultivars. All stresses increased total protein contents of shoots in Texas only but decreased or had no effect on others. Root total protein increased under salinity stress, while drought had no effect. Changes in proline and sugars in both shoots and roots did not follow any particular pattern. Out of the biochemical compositions measured, shoot total protein in plants under the stresses showed a positive significant correlation with SDW, which may be used to screen onion cultivars for drought and salinity stresses.
S. M. J. Nazemosadat, A. R. Ghasemi,
Volume 8, Issue 4 (1-2005)
Abstract
The influence of the Sea Surface Temperatures (SSTs) on the seasonal precipitation over northern and southwestern parts of Iran was investigated. The warm, cold and base phases of the SSTs were defined and the median of precipitation during each of these phases (Rw, Rc and Rb, respectively) was determined. The magnitude of Rw/Rb, Rc/Rb and Rc/Rw were used as criteria for the assessment of the effects of the alternation of SST phases on seasonal precipitation. The results indicate that in association with cold SST phase, winter rainfall is above median over western and central parts of the coastal region, central and southern parts of Fars Province and all the stations studied in Khozestan Province. On the other hand, the prevalence of warm SST phase has caused about 20% decrease in winter precipitation over the Caspian Sea coastal area and northern parts of both Fars and Khozestan provinces. In association with warm SST phase in winter, precipitation during the following spring was found to be above normal for all the stations studied in the coastal region of the Caspian Sea. The highest sensitivity levels were found in Bandar- Anzali and Astara for which spring precipitation has increased by 80% due to the dominance of warm winter phase. However, the occurrence of boreal cold SST events causes shortage of precipitation in the eastern parts of the coastal areas along the Caspian Sea. A Possible Physical mechanisem justifying the influence of the Caspian Sea SST on the Precipitation variability was introduced. According to this mechanisem, temporal and spatial variability of the Siberian High is forced by the fluctuations in these SSTs.
M. Akhondi, A. Safarnejad, M. Lahouti,
Volume 10, Issue 1 (4-2006)
Abstract
Drought stress is one of the most important environmental stresses in reduce of growth and plants production. Determination of resistance mechanisms to environmental stress in plant improvement is very important. In order to , experiment with osmotic potentials of PEG (zero (control), -4, -8 & -12 bar) and alfalfa genotypes was done. The selected alfalfa genotypes namely, Yazdi(tolerant), Nikshahri(moderate) and Ranger(sensitive) were grown in hydroponic culture. After 4 weeks, they were harvested in order to determination of proline accumulation and Ca+2, K+ and Na+ concentration. The data showed with increasing of drought stress, proline accumulation were increased, but its rate was different among genotypes and organelles. Concentrations of K+, Na+ and Ca2+ increased with increasing of osmotic stress and there was significant different between genotypes. The K+/Na+ ratio in the shoots and roots of plant was decreased, when drought stress increased. Morphological and biochemical data showed Yazdi genotype was more tolerant to drought stress in compare with studied genotypes.
M. Bagheri Mofidi, M. Bahar, H. Shariatmadari, M. R. Khajehpour,
Volume 10, Issue 2 (7-2006)
Abstract
To investigate drought tolerant isolates of rhizobial symbioant of lentil (Lens culinaris L.), 12 soil samples were collected from cultivated and non-cultivated area of Golestan, Chaharmahal-O-Bakhtiari and Isfahan provinces. Local cultivars of lentil including Binam Dorosht, Ghazvini and Faridani were planted in each soil sample. After 10 weeks, a total of 324 rhizobial isolates were recovered from root nodules of the lentil plants. Evaluation of the ability of the isolates to grow at different concentration of salt showed that all isolates grew normally on 200 mM NaCl and only 20% was determined as salt tolerant isolats(>400mM). Among the isolates RL249 was classified as superior salt tolerant strain due to growing on 600 mM salt. The drought tolerance of the isolates was also examined, using PEG6000. In general, the salt tolerant isolates were also drought tolerant, however their tolerance to salinity and drought is not related to their geographical origin. In a randomized split factorial design with three replications, the effectiveness of tolerant isolates(RL249 and RL211) and a sensitive strain (RL 77) was compared on two cultivars of lentil (Binam Dorosht and Faridani) under water stress treatments with the consumptions of 50, 75,90 and 98% of soil available water. Although nodulation rate was reduced in both cultivars as the consequence of drought stresses, plants of Binam Dorosht cultivar showed high nodulation rate due to the increased fresh weight of the roots. Despite the fact that RL249 was identified as a superior nodulating and salt/drought isolate, however nodulation efficiency was decreased significantly under water stress treatments with more than 50 % of soil available water.
A. Fatehi Marj, A. Borhani Darian, M. H. Mahdian,
Volume 10, Issue 3 (10-2006)
Abstract
Orumiyeh Lake basin is one of the important regions in Iran from water resources and environment standpoints. In this basin, substantial part of the annual precipitation occurrs in spring, winter, and fall seasons. Due to semi-arid climate of the basin, rainfall forecasting is an important issue for proper water resources planning and management, particularly in drought years. On the other hand, investigations around the world show that there is a good conection between climatic signals and the amount of precipitation. In this paper, the relationship between climatic signals and seasonal rainfall was investigated in Orumiyeh Lake basin. For this purpose, monthly SPI (Standard Precipitation Index) was calculated and used along with six climatic signals including SOI (Southern Oscillation Index), PDO (Pacific Decadal Oscillation), PNA (Pacific North America), NAO (North Atlantic Oscillation), NINO3.4 and, NOI (North Oscillation Index). A new method employing the negative and positive phases of signals was proposed and tested to distinguish the relationship between the climatic signals and the individual stations rainfall in the basin. Furthermore, it was found that using joint signals substantially improves the precision of the forcast rainfalls. The results showed that fall and winter rainfalls had the highest correlatetions with SOI and NAO, respectively. Therefore, it would be possible to forecast the basin rainfall using climatic signals of the previous seasons.
M. R. Jazayeri, A. M. Rezai,
Volume 10, Issue 3 (10-2006)
Abstract
This study was conducted at the Research Farm of Isfahan University of Technology in 2003 to evaluate drought tolerance potential of 20 oat (Avena sativa L.) genotypes including 14 cultivars released in Canada, two cultivars released in the United States of America and Switzerland and four Turkish breeding lines. A randomized complete block design with three replications was used in each irrigation treatment (i.e., irrigation after 70±3 and 130±3 mm evaporation from class A pan). Results of analysis of variance revealed significant differences among cultivars for all studied traits in both irrigation treatments, with the exception of plant height at heading stage and biological yield in stress condition. Stress condition significantly reduced all the traits. Also, the interaction of genotypes by irrigation treatments was significant for days to heading, grain and biological yields and 1000-grain weight. To evaluate drought tolerance of the studied cultivars, Rosielle and Hamblin tolerance index, mean productivity (MP), Fischer and Maurer stress susceptibility index and Fernandez geometric mean productivity and stress tolerance index were calculated based on yield data in stress and non- stress conditions. According to the obtained results, stress tolerance index seems to be the most effective index to identify tolerant genotypes. Rank correlations of stress tolerance index and grain yields in stress and non-stress conditions were 0.93 and 0.78, respectively. Based on this index, Boyer and Paisley were found to be the most tolerant cultivars.
Kh. Abolhasani, G. Saeidi,
Volume 10, Issue 3 (10-2006)
Abstract
This experiment was conducted to evaluate drought tolerance of selected lines from local populations of safflower (Carthamus tinctorius L.) at the Research Farm of Isfahan University of Technology in 2002. In this study, the 12 selected safflower lines from different local populations along with two exotic cultivars and a local population were evaluated at two different irrigation regimes, using a randomized complete block design with three replications. The first and second irrigation regimes were based upon the depletion of 50% and 85% of soil moisture content, respectively. The results showed that there were significant differences (p<0.01) among the genotypes for seed yield in both irrigation regimes. Also, the interaction between genotypes and irrigation regimes was significant (p<0.05). Based upon the genotype by environmental interaction analysis (method of Sneller and Dombek), the genotype H27 had the highest tolerance to drought stress, and its seed yield in the first and second irrigation regimes was 3353 and 3072 kg/ha, respectively. The growing variety in Isfahan province (Koseh population) was the most sensitive genotype to the drought stress and had a seed yield of 3525 and 2394 kg/ha in the above irrigation regimes, respectively. The assessment of different water stress indices (SSI, STI, TOL, GMP and MP) revealed that STI seems to be the most suitable index for recognizing the more tolerant genotypes to drought conditions and based on this index, E2428 was the most tolerant genotype, and the exotic cultivar of Ac-Sunset (from Canada) was the most sensitive one. The seed yield for genotype E2428 was 4174 and 3458 kg/ha, and for the genotype Ac-Sunset was 2004 and 1438 kg/ha in the first and second irrigation regimes, respectively.
S. Sharif, M. Saffari, Y. Emam,
Volume 10, Issue 4 (1-2007)
Abstract
Many experiments have been carried out to alleviate the negative effect of drought stress and to obtain suitable growth under water deficient condition. Application of plant growth regulators (especially growth retardants) is one of the proposed methods. In a greenhouse experiment using a completely randomized block design with 4 replications at Kerman University Agricultural Department, the effect of 4 drought levels 25, 45, 65, 85 percent of field capacity and 3 different concentrations of chlormequat chloride 0, 1500, and 3000 mg/liter on some factors of winter barley cultivar Valfajr was investigated. Results indicated that increasing the cycocel concentration from 0 to 3000 milligram per liter leads to significant decrease in plant height. Relative water content affected by growth retardants was increased. Numbers of tillers and root and shoot dry weight, were also decreased because of applying cycocel in dry condition. The result also indicated that the root/shoot dry weight ratio, grain number per ear and ear number in dry condition without stress would increase using cycocel treatment.
M .tousi Mojarrad, M. R. Ghannadha,
Volume 10, Issue 4 (1-2007)
Abstract
In order to evaluate grain yield potential and study dry matter remobilization to seed, 8 commercial bread wheat cultivars were examined in two separate experiments, using randomized complete block design with 4 replications in 2003. There were significant differences for most traits in normal and drought conditions. Sarday variety had the least grain yield in the two environments. There was considerable variation between genotypes for independent parameters of dry matter remobilization to different plant parts in the two environments. Factor analysis showed that seven factors accounted for 100 % of the data total variance in normal and drought conditions. Factor analysis also showed that the effective traits to components grain yield , height and phenological traits were important for the selection of appropriate genotypes. Calculation of drought resistance indices showed that four indices including mean productivity, geometric mean productivity, harmonic index, stress tolerance index were more effective than other indices for the selection of drought tolerant genotypes.
J. Ahmadi, S.f.orang, A.a. Zali, B. Yazdi – Samadi, M. R. Ghannadha, A. R. Taleei,
Volume 11, Issue 1 (4-2007)
Abstract
Generation mean analysis (GMA) was used to study the type of gene action and inheritance of grain yield and its components. Generation mean analysis with joint scaling test was performed. This research was conducted at research farm of college of Agriculture at the University of Tehran. The parents and their progenies ( F1, F2, BC1 & BC2) in three mating groups ( Sardari × 7007, Sardari × 7107& 7107 × 5593) were produced and planted using a randomized complete block design with four replications for each mating group. Of four replications in each experiment, two replications for drought and two replications for non-drought condition were used. The eight traits which were evaluated included grain yield, plant height, plant weight, tiller number, spike length, grains per spikes and 100 grain weight. Most of the genetic parameters including mean (m), additive (d), dominant (h), additive × additive [i], additive × dominant [j], and dominant × dominant[l] effects were significant. However, all gene effects were not significant in all traits.The dominant gene effect was the most contributor factor to inheritance of the majority of traits. For the majority of the traits, additive gene effect was significant, but its magnitude was less than dominant gene effect. Also the dominant × dominant[l] epistasis was more important than additive× additive [i] epistasis. The degree of dominance in most of traits indicated the predominance of dominant gene effects.
M.j. Seghatoleslami, M. Kafi, I. Majidi, G. Nour-Mohammadi, F. Darvish,
Volume 11, Issue 1 (4-2007)
Abstract
In order to examine the responses of proso millet (Panicum miliaceum) to drought stress at different growth stages, four breeded genotypes and a local one of proso millet were selected and planted in a split-plot design with five irrigation treatments and three replications.This experiment was conducted in two locations, Birjand and Sarbisheh. Irrigation treatments included well - watered, drought stress at vegetative stage, ear emergence stage, seed filling stage and vegetative and seed filling stages which were considered as main- plots. The first five mentioned genotypes were considered as sub-plots. Drought stress. caused a great reduction in grain yield and WUE at ear emergence stage. This reduction represented itself in the number of seed per ear and the weight of seeds, but it didn’t have any effects on the number of ear. At ear emergence stage, the drought stress increased the floret death and loss of weight of seeds which resulted in the reduction in the harvest index of both ear per plant and seed per plant. Comparison of genotypes indicated that since K-C-M.4 had a greater number of ears and K-C-M.9 had heavier seeds that had higher grain yield. These two genotypes had the highest WUE and their harvest indices were relatively higher. Due to the salinity of water and infertility of soil in Birjand, the grain yield was lower compared with Sarbisheh. In summary, it can be said that genotype K-C-M.4 proved to be more suitable for both areas.
Y. Emam, A.m. Ranjbar, M. J. Bahrani,
Volume 11, Issue 1 (4-2007)
Abstract
Drought stress is one of the major limiting factors of crop yield. A field experiment was conducted to study the effects of drought stress on yield and yield components of nine bread wheat and one durum wheat genotypes during 2003-2004 growing season. The experiment was designed as two separate randomized complete blocks design with three replicates under well-watered and unwatered conditions during the post-anthesis period. Post-anthesis drought stress reduced the grain yield and yield components in all genotypes. Mean of each trait significantly(p≤%5) decreased under drought stress conditions, except for spikeletes number per spike and ear number per square meter. The highest yield loss was caused by the grain number per ear and 1000- grain weight reduction under drought stress conditions.“Gahar” genotype had the highest grain yield (4149 kg/ha) under drought stress conditions, whereas the highest grain yield (6674 kg/ha) was obtained for “Nikenejad” genotype under optimum conditions. Based on stress susceptibility index, “Koohdasht” and “Boholh-15” genotypes showed the lowest and the highest yield loss in response to drought stress, respectively. Correlation analysis of yield and yield components indicated that, under drought stress conditions, ear number per square meter (r=0.751) and biological yield (r=0.707) had the highest correlation with the grain yield(p≤%5), whereas these traits were grains number per ear(r=0.864) and biological yield (r=0.848) for the well-watered conditions. Therefore, it might be possible to select genotypes for greater grain yield with the means of the traits which have the highest correlation coeficient with the grain yield under each moisture regime. Generally, it appeared that “Gahar”and “Nikenejad” genotypes with greater yield potential might be recommended for agronomic conditions similar to the present investigation.
M. Golestani, H. Pakniyat,
Volume 11, Issue 41 (10-2007)
Abstract
To investigate genetic variation, and identification of tolerant genotypes according to quantitative indices of drought tolerance, 8 sesame genotypes were tested in a randomized complete block design with three replications under optimum and limited irrigation at the Research Station of College of Agriculture, Shiraz University. Based on the potential yield and yield under stress, quantitative indices of drought tolerance such as mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM), stress tolerance index (STI), stress susceptibility index (SSI) and tolerance index (TOL) were determined. The result of analysis of variance exhibited highly significant differences among the genotypes for all the indices measured, and yield under optimum and limited irrigation, indicating the existence of genetic variation among genotypes, and thus the possibility of selecting drought tolerant genotypes. Mean comparison displayed that the highest potential yield, stress yield, MP, GMP, HM and STI were related to the genotype number 5. Correlation analysis between indices, mean potential and stress yields indicated that every four indices are suitable for screening the genotypes. Based on these indices and higher yields under optimum and limited irrigation the best drought tolerant genotypes were identified to be genotypes number 4 and 5. Multivariate biplot indicated that the genotypes number 4 and 5 were located next to the vectors of drought tolerance indices, including MP, GMP, HM and STI. Cluster analysis showed genetic distance among genotypes. As a result, genotypes number 4 and 5 were identified as drought tolerant and genotypes number 1, 2 and 3 as susceptible to drought.
S. Morid, S.h. Paymozd,
Volume 11, Issue 42 (1-2008)
Abstract
Application of meteorological indicators has extensive use in drought monitoring. However, hydrological indicators can also play an effective role in this task. In this research, one of the rare approaches in drought monitoring with hydrological indicators namely Chang method has been applied and assessed for the Tehran basin using daily time step. The results have been compared with the unique meteorological drought index, EDI (effective drought index) and show the capabilities of the hydrological method and its more sensivity to water resources deficit. For instance, application of these procedures for the 1998 to 2000 drought spell in Tehran province revealed that Change method declares 31.1 % of times in very severe drought whereas it is 3.7 in EDI. Because of applying different indicators (e.g. reservoir and ground storage), a combination of both procedures is an ideal approach for drought monitoring in which the water inputs to the system as well as storage and consumptions are considered. The applied methodology makes it Possible to distinguish droughts due to rainfall deficit from the ones, which are resulted from water resources miss management.
M. Tousi Mojarrad, M.r. Ghannadha,
Volume 12, Issue 43 (4-2008)
Abstract
In order to study inheritance of traits (Height, Peduncle length, Extrusion peduncle length, Diameter first internode, Diameter secondary internode, Diameter third internode length of secondary internode, length of third internode) associated with height in bread wheat, seven cultivars of bread wheat with their F1 progenies produced through a half diallel mating design were planted in a randomized complete block design with 3 replications in normal and drought conditions in the Seed and Plant Improvement Institute, Karaj, in 2004. Analysis of variance showed significant differences for all the traits in normal and drought conditions at 1 % probability level. Diallel analysis showed that general combining abilities were significant for all the traits in normal and drought conditions at 1% level of probability. The specific combining abilities were not significant except for extrusion peduncle length and length of secondary internode. Additive effect was more important in controlling all the traits. Height had the most broad sense and narrow sense heritabilities in normal and drought conditions. It was also found that increasing all the traits except for plant height and length of the third internode was controlled by the dominance alleles in normal and drought condition. The analysis of traits revealed more mean traits in progenies compared to parents in both normal and drought conditions. Sardary and Roshan varities showed the best general combining ability in normal and drought conditions.
M. Keshavarz , E. Karami ,
Volume 12, Issue 43 (4-2008)
Abstract
Drought is an unavoidable natural disaster in dry and arid regions of the world. Studies indicate that Iran with its geographical and climatic characteristics is poor in water resources. Moreover, it is estimated that in 2025, Iran should increase the water resources by 112% in order to maintain status quo. Therefore, the occurrence of drought is more prevalent in the future. This implies a real challenge for researchers to study how to manage farms during the onset of drought. Inappropriate management strategies result in loss of resources, which in turn leads to more destructive impacts of drought, consequently leading to more droughts in future. The purpose of this survey study was to identify factors influencing drought management among farmers in Fars province, Iran. A multistage stratified random sampling technique was used to select a representative sample of farmers who has experienced drought in recent years. A total of 258 farmers were interviewed using a questionnaire. A panel of experts verified face validity. A pilot study was used to assess the reliability of the measuring instrument. Cluster analysis and Structural Equation Modeling were used for data analysis. Results indicated that farmers with different social, economical, and technical characteristics chose different management strategies when coping with drought conditions. Despite farmers' efforts to manage drought, they face harsh consequences. These consequences include economic losses and degradation of farming environment. It is therefore recommended that policy makers who are involved in drought management programs learn more about farmers' drought mitigation techniques and make further attempts to increase the efficiency and effectiveness of techniques used by farmers.
E. Rahmani, A. Khalili, A. Liaghat,
Volume 12, Issue 44 (7-2008)
Abstract
The growing season climatic parameters, especially rainfall, play the main role to predict the yield production. Therefore, the main objective of this research was to find out some possible relations among meteorology parameters and drought indexes with the yield using classical statistical methods. To achieve the objective, ten meteorological parameters and twelve drought indexes were evaluated in terms of normality and their mutual influences. Then the correlation analysis between the barley yield and the climatic parameters and drought indexes was performed. The results of this study showed that among the drought indexes, Nguyen Index, Transeau Index, Rainfall Anomaly Index and Standardized Precipitation Index (SPI24) are more effective for prediction of barely yield. It was also found that the multivariate regression is better than the univariate regression models. Finally, all the obtained regression models were ranked based on statistical indexes(R,RMSE and MBE). This study showed that the multivariate regression model including wind speed, sunshine, temperature summation more than 10, precipitation and Nguyen index is the best model for prediction yield production in Miane. Average wind speed and Nguyen index were recognized to be the most effective parameters for yield production in the model.
A. M. Rezai, M. Yousofi Azar,
Volume 12, Issue 45 (10-2008)
Abstract
To improve a complex character such as yield with low heritability, the use of indirect selection through other characters and a selection index based on different effective traits is recommended. This study was conducted to evaluate different selection methods by using 23 F2:4 wheat lines derived from the cross of Virmarin (susceptible cultivar) and Sardari (tolerant cultivar) at Research Farm of Isfahan University of Technology. A randomized complete block design with three replications was used in two irrigation treatments (i.e. irrigation after 70±3 and 120±3 mm evaporation from class A pan). For each irrigation treatment, different selection indices were constructed based on the number of spike per m2, days to heading, number of grain per spike and 1000 – kernel weight. Also direct and correlated responses were calculated for these traits. The results of the response to selection and correlated response indicated that in the same conditions of this study, early heading cultivars with high number of spikes and low number of grain per spike with high 1000-kernel weight will have more yield potential. Number of spike per m2 and 1000-kernel weight exhibited positive response in most of the indices and both irrigation treatments, while days to heading and number of grain per spike revealed negative responses. Thus selection based on these indices would result in early heading cultivars with high spike per m2, low number of grain per spike and high 1000–kernel weight. It was also found that Smith-Hazel and Brim-Williams indices had the highest efficiencies.
