فهرست مطالب اشکبوس امینی سفیداب

Due to limited water resources in the country, irrigated wheat cultivars in cold and temperate cold regions are faced with lack of irrigation or limited irrigation at the end of the season. In these areas, most farmers who cultivate irrigated wheat due to lack of sufficient water in the spring cannot perform enough irrigation and therefore do not get the desired result from cultivating high-yielding cultivars. Development of new cultivars with high grain yield under terminal drought stress conditions is one of the major goals of wheat breeding program for cold regions of country. Heyran new bread wheat cultivar introduced from International Research Center for Maize and Wheat (CIMMYT) to Iran through an international nursery in 2010 and was evaluated in a primary trial in four research stations (Karaj, Jolge-Rokh, Ardabil and Mashhad), and due to its favorable characteristics was selected for further evaluation in preliminary yield trials in cold regions. This line showed grain yield of 8417 kgha-1 under normal irrigation compared to the check cultivars Orum, Zareh and Mihan (with average yields of 7679, 6828 and 7772 kgha-1, respectively), and under terminal drought conditions with an average seed yield of 4653 kgha-1, compared to the check cultivars Orum, Zareh and Mihan (with average yields of 4375, 3544 and 4358 kgha-1, respectively) and was selected in both conditions. Aforementioned line showed grain yield of 8340 kgha-1 in advanced yield trial of cold regions breeding program under normal conditions compared to check cultivars Orum, Zareh and Mihan (with average yields of 7518, 7613 and 8205 kgha-1, respectively) in five locations, selected for final evaluation in adaptability test. Grain yield of this line which was presented as CD-92-6 at the adaptability test was 4470 kgha-1 against 3711 and 3743 kgha-1 of Zareh and Mihan checks cultivars under water stress conditions, respectively, during two cropping seasons 2013-14 and 2014-15. This line showed overall mean grain yield, of 5143 kgha-1 under terminal drought stress conditions in extensional farmer’s fields. For these conditions checks cultivars Hydari and Mihan showed grain yields of 4808 and 4758 kgha-1, respectively. Grain yield potential of this line was recorded as 6323 kgha-1 in Khorasan Razavi farmers' field. According to the latest evaluations the response of this line to yellow rusts was resistant to semi sensitive under severe artificial infection. Wheat line CD-92-6 has considerable cold tolerance and good bread making quality and based on its good agronomic characteristics in 2019 this line was released as Heyran, for cultivation under terminal drought stress conditions in the cold agro-climatic regions.

Salinity stress is a major constrain of plant growth and limiting factor of crop production in arid and semi-arid regions in the world. Wheat cultivar Barzegar is derived from the cross between an Iranian highly adapted wheat, Pishtaz cultivar and Karchia cultivar (salt tolerant cultivar from India) as female and male parents, respectively, at Seed and Plant Improvement Institute, Cereal Research Department in Karaj. Subsequent selection among segregating populations of this hybrid was done at experimental field of Yazd station. Results of yield trials and on-farm evaluations in the temperate zone showed that under salinity stress conditions (EcSoil =8-12 dsm-1 & EcWater =8-13 dsm-1), Barzegar exhibited a superior performance compared to the check cultivars Bam and Arg, and its average grain yield was 659 kg (16.5%) higher than average grain yield of check cultivars. Based on ranking method Barzegar had high stability and adaptability under saline conditions compared to the check cultivars. Under farmer's conditions trials its average grain yield was 4381 kgha-1, nearly 20% higher than average grain yield of check cultivars (3648 kgha-1). Barzegar exhibits lodging resistance and has non-shattering spikes, but has moderately resistant susceptible infection responses to rusts. However, under dry conditions of saline areas of Iran no susceptibility to these diseases is observed. Based on good agronomic performance consist of resistance to lodging and shattering, and high adaptability and stability and good quality in saline condition compared to checks (Bam, Arg and Ofogh), Barzegar released for cultivation in the saline areas (with saline water/soil) farms of temperate zone, in Iran.

This research was conducted to compare the salinity tolerance of wheat promising lines during 2015-2017. The greenhouse experiment was carried out at Seed and Plant Improvement Institute, Karaj, Iran, and the field experiment was conducted at National Salinity Research Center, Yazd, Iran. The treatments in greenhouse experiment were irrigation water salinity at two levels (2 and 14 dS.m-1) and five wheat genotypes (MS-89-13, MS-89-12, MS-90-13, MS-90-15 and Narin as check, and in the field experiment including salinity of irrigation water at five levels (2, 5, 8, 11 and 14 dS.m-1) and the same five wheat genotypes mentioned above. The results of greenhouse experiment showed that salinity stress of 14 dS.m-1 significantly decreased plant height, leaf area, shoot fresh and dry weight and root length and dry weight in all genotypes and increased chlorophyll index only in MS-89-12 genotype. Narin as well as MS-90-15 and MS-90-13 genotypes with the lowest reduction percentage due to salinity stress were determined as the most tolerant genotypes. The results of field experiment also indicated that salinity stress, depending on its severity, significantly reduced plant height, ear length, fertile spikelet number in ear, grain number per spike and thousand grain weight, which led to considerable decrease in grain and biological yield. Under control conditions (2 dS.m-1), the highest and lowest grain yield were obtained from MS-90-13 and Narin (6.91 and 5.81 t.ha-1, respectively), and under 14 dS.m-1 salinity conditions, Narin and MS-90-15 genotypes had the highest and lowest grain yield (3.23 and 1.51 t.ha-1, respectively). The threshold levels of salinity tolerance for MS-89-13, MS-90-13, MS-90-15, Narin and Ms-89-12 were evaluated to be7.41, 6.30, 4.92, 4.84 and 4.20 dS.m-1, respectively. The results showed that MS-89-13 had the higher salinity tolerance at salinity of less than 8 dS.m-1, but at higher salinity levels, Narin and MS-90-13 genotypes similar to greenhouse experiment were more tolerant than the other genotypes. According to the relatively similar results of greenhouse and field experiments, MS-90-13 line for lower salinity levels and Narin variety and MS-90-15 line for higher salinity levels were the more suitable genotypes, which could be recommended with due to considerations.

Yield stability and genetic variation in 17 salt-tolerant bread wheat promising lines and three cultivars; Arg, Bam and Ofough were evaluated in field trials as well as by molecular assay. In field, yield trials of genotypes was carried out in saline soils of Melishbar (Yazd), Amirabad (Birjand), Roudasht (Isfahan), Ekhtiarabad (Kerman) and Zahak (Zabol) agriculturar research stations, Iran, in 2012-13 and 2013-14 cropping cycle. To evaluate genetic variation among genotypes, 18 SSR markers that were previously mapped on salt-tolerant quantitative trait loci (QTLs) were used. Combined analysis of variance revealed significant differences for genotype main effect and year × location, year × genotype and year × location × genotype interaction effects. Grain yield comparison of genotypes using least significant difference(LSD) test showed that lines 14, 16, 11 and 5 with grain yields of 4.649, 4.517, 4.441 and 4.300 tha-1 had higher grain yields among genotypes. Different methods of stability analysis revealed that genotypes 11, 15, 16 and 20 (cultivar Ofough) had higher yield stability compared to the other genotypes. Cluster analysis of molecular data using UPGMA method and principal component analysis (PCoA) classified studied genotypes into four major groups. Results of cluster analysis based on molecular data were not in agreement with the results of field experiments. Results of Mantel’s test indicated that correlation between grain yield under salinity stress conditions and their allelic diversity was about 0.13 and not-significant. Despite this weak correlation, SSR markers could greatly reveal genetic variation among wheat genotypes. This genetic variation can effectively be used in wheat breeding programs for salt tolerance in Iran.

In arid and semi-arid regions of the world including Iran, soil salinity is one of the major abiotic stresses. One of the ways to achieve high performance in these areas is using salt tolerant varieties. Also, study on relationships between yield and its components will improve the efficiency of a breeding program with appropriate selection criteria. In this study, 110 bread wheat genotypes were evaluated in two conditions (non-stress and saline stress) at the research field of the National Salinity Research Center (NSRC). The salinity of water used in irrigation in saline and non-stress conditions was 10 and 2 dS.m-1 respectively. In this study was used of stress tolerance index (STI) as the best indicators for evaluating of tolerant to salinity stress of bread wheat genotypes. Based on stress tolerance index (STI)and seed yield in non-stress and saline stress conditions, the linesSalt18, Salt19, Salt20, Salt21, Salt22, Salt23, Salt24, Salt25, Salt26, Salt27, Salt28, Salt29, Salt30, and varieties Arg, Bam, Rushan, Sorkhtokhm, BumiYazd, Kavir, Moghan 1, Sardari, Sharyar, Shirazhad had a high yield in the non-stress and saline stress conditions and these genotypes were selected as the most tolerant genotypes to salinity.The highest grain yield under non-stress and saline stress conditions was produced by Salt29 line (178.13 gr) and Salt24 line (164.33 gr), respectively which had more grain yield than control cultivars (Arg, Bam, Rushan, Sorkhtokhm, Bumi Yazd and Karchia). Also, based on the results of sequential path analysis, kernel weight per spike and number of fertile tillers in non-stress conditions and spike weight, number of fertile tillers, days to headingand peduncle weightin saline stress conditions were selected as first order variables.Therefore, it seems that these traits could be used as a suitable criterion in wheat breeding programs for increased seed yield in both non-stress and salinity stress conditions.

Salinity stress is a major constrain of plant growth and limiting factor of crop production. Wheat cultivar Narin is derived from the cross between an Iranian salt tolerant wheat line (1-66-22) and Pishtaz cultivar as female and male parents, respectively, at Seed and Plant Improvement Institute, Cereal Research Department in Karaj and subsequent selection among segregating populations done at experimental field of Yazd station.Results of yield trials and on-farm evaluations in the temperate and warm zone showed that under salinity stress conditions (EcSoil =8-13 dsm-1&EcWater =8-11 dsm-1), Narin exhibited a superior performance compared to the check cultivars Bam, Kavir, Neishoubour and Roshan, and its average grain yield was 809 kg (19% Percent) higher than average grain yield of check cultivars. Based on ranking method Narin had high stability and adaptibility in saline condition compared to check cultivars. Unser farmer`s conditions, its average grain yield was 4474 kg ha-1, nearly 22% higher than average grain yield of check cultivars (3664 kg ha-1). Narin exhibits lodging resistance and has non-shattering spikes, but has moderately resistant to moderatelt susceptible infection responses to rusts. However, under dry conditions of saline areas of Iran no susceptibility to these diseasesis observed. Based on good agronomic performance such as early maturity, resistance to lodging and shattering, and high adaptability and stability and good quality under saline conditions compared to checks (Bam, Arg and Ofogh), Narin was released for cultivation in saline areas (with water/soil salinity) of temperate and warm zone in Iran.

A breeding hexaploid salt tolerant wheat line (MS-81-14) was produced from crossing of an Iranian salt tolerant wheat line (1-66-22) with Inia cultivar (from CIMMYT) at Karaj Research Station in 1991-92 cropping season. The F1 plants were grown at Karaj in 1992-93 cropping season، furthermore F2-F6 populations were evaluated under salinity stress conditions (EcSoil&Water = 8-12 ds/m) in Isfahan (Rodasht Agricultural Research Station) during 1993-1999 cropping seasons. An extracted breeding line was evaluated in the preliminary yield trial of Yazd and Neishabour Stations and was picked based on its high yield as well as its good performance under salinity stress conditions in 1999-2000. This line was further tested in the preliminary regional yield trial of salt affected regions of temperate zone at two stations (Yazd and Isfahan) and with recorded yield of 6. 483 tha-1 against 4. 893 and 4. 400 tha-1 of Kavir and and Roshan check cultivars، respectively was selected again in 2000-01. This line was tested in advanced and replicated trials over four stations (Yazd، Zabol، Kerman and Isfahan) in 2001-02 and with recorded grain yield of 5. 55 tha-1 compared to 4. 145 and 4. 185 of Kavir and Roshan check cultivars، respectively under salinity stress conditions، as a superior line forwarded to adaptation trials. The adaptation and stability of this line were evaluated in a two years experiment tested over three stations (Yazd، Birjand and Isfahan) during 2002-2004 periods under salinity stress conditions (EcSoil = 8-14ds/m، EcWater= 8-12 ds/m)، and with grain yield of 5. 470 tha-1 against 4. 650، 4. 499 and 4. 962 tha-1 of Kavir، Roshan and Bam check cultivars، respectively and due to its high stability (with Ys=23 against Ys= 8،7 and 17 of Kavir، Roshan and Bam check cultivars، respectively)، high adaptability and good bread quality was considered as the most stable line for on-farm and extension trials which was followed in 2004-08 over different salt affected regions of temperate zone showing an average grain yield of 4. 232 tha-1 for MS-81-14 against 3. 673 and 3. 769 tha-1 of Bam and Kavir check cultivars، respectively. The results of farmer conditions trials confirmed the wide adaptability and grain yield stability of the new line. Considering high grain yield، high adaptability and stability for saline areas and good grain quality (protein contents of 11. 9% and hardiness index of 50 as well as good agronomic performance including resistance to lodging and shattering، this line named Arg and officially released in 2009 for cultivation in saline areas (with water/soil saline) farms of temperate zone، in Iran.