r. roohparvar

Stem rust, or black rust, caused by the fungus Puccinia graminis f. sp. tritici, poses a severe threat to global food security, potentially devastating wheat crops on farms. The damage of this disease in the epidemic condition is 100% of the wheat crops. Frequent epidemics of stem rust have been reported in different regions of the world in the past years. The most effective method to control this disease is identifying and incorporating effective resistance genes from resistant cultivars into desirable wheat genotypes, for establishing durable genetic resistance.

To identify new sources of resistance, an experiment was conducted to investigate the resistance reactions of 30 wheat genotypes and a susceptible check (Morocco) against six Pgt races with distinct pathogenicity patterns (TKTTF, TTTF, TTRTF, PKRTF, PKSTF, and TKSTC). The experiment employed a randomized complete block design with three replications. Each race of Pgt was used separately to evaluate the genotypes.

Phenotyping and analysis of variance (ANOVA) revealed significant phenotypic diversity among wheat genotypes for the measured resistance components (infection type and latent period). Cluster analysis classified the wheat genotypes into three main groups: resistant, susceptible, and moderately resistant to moderately susceptible. Among the wheat genotypes studied, 11 genotypes (35%) exhibited susceptibility to all races, while four genotypes (G1, G2, G3, and G17) (13%) demonstrated resistance to all races. The remaining 16 genotypes (52%) showed moderately resistant to moderately susceptible (specific reaction) responses. The biplot analysis (GGE biplot) identified genotype G17 as the most resistant genotype with a uniform response to all races.

Genotypes with varying degrees of resistance to Pgt races identified in this study can serve as new and sustainable sources of resistance for breeding wheat cultivars with a broad genetic basis of resistance. The use of more races and differential isogenic lines can make it possible to provide more specific conditions to identify the effective resistance genes in each genotype more accurately. Evaluating the resistance of the examined genotypes at the adult plant stage can also lead to the identification of resistance genes at the adult plant stage which are more important than the seedling stage resistance genes. The existence of resistance genes at adult plant stage is not far from expected even if the genotype is sensitive in the seedling stage. It is hoped that the correct, and planned use of effective resistance genes at the seedling stage and adult plant stage together will lead to the creation of new stable resistant varieties.

A new durum wheat cultivar, Taban (DW-92-5) was initially introduced as a breeding line through 42ed International Durum Screening Nursery (42ed IDSN) received from the International Maize and Wheat Improvement Center (CIMMYT) and was evaluated in two research stations of Dezful and Darab in warm agro-climate zone of Iran. In this step, DW-92-5 (Taban) was selected for the further studies based on its high grain yield (7492 kgha-1). This line with 6976 kgha-1 average grain yield was close to Behrang as a control cultivar with 7198 kgha-1 in the regional preliminary yield trial in 2011-2012 cropping season. Line DW-92-5 had an average grain yield of 7782 kgha-1 in the advanced yield trials and was selected for the further evaluations. The regional elite yield trials was conducted in four stations of Ahvaz, Darab, Dezful and Khorramabad in 2013-14 and 2014-15. This line with 6669 kgha-1 had 12% higher yield than Behrang check cultivar with grain yield of 5935 kgha-1 and was selected as superior line based on its grain yield and yield stability. Taban also has high quality of semolina, high protein content (13.2%). The results of on-farm trials showed that this cultivar exhibited a 12% and 13% higher grain than Shabrang and Behrang, respectively, as local checks in Sistan and Baloochestan province as well as a 2% and 18% higher grain yield compared to Behrang and Yavarous as local checks in Kerman province. In total, based on its high grain yield, yield stability, quality of semolina and its good level of resistance to yellow and leaf rusts, line DW-92-5 was released as a new durum wheat cultivar with the name of “Taban” for warm agro-climate zone of Iran.

Kamal, is a new winter bread wheat cultivar developed by the national rainfed bread wheat breeding program for the cold and temperate dryland areas of Iran. New cultivar created by crossing between Sbn//Trm/k253 and 88Zhong218//Ctk/Vee/3/Kvz/Gv//Prl in Maragheh Research Station. Kamal was selected from segregating population from F2-F7 in Maragheh (2002-2008) based on agronomic characteristics. Based on results, Kamal grain yield means in preliminary and advanced regional yield trail was 2234 and 1719 kgha-1, respectively. Results of elite trail in cold and moderate research stations (2012-2015) showed that the grain yield mean of Kamal was 2120 and means of Azar2 and Ohadi cultivars were 2066 and 2083 kgha-1, respectively. Kamal cultivar in East Azerbaijan province was compared with conventional control cultivars in the farmer fields for 3 years and the results showed that the average grain yield of Kamal and checks were 2604 and 2230 kgha-1 respectively. Kamal is a winter type variety with time to heading of 143 days, 67 cm plant height, 40, gr. 1000 kernel weight, 11.4% protein content, 20 ml Zeleni numer, 41 degree of hardness, 27% wet gluten and 15 unit of gluten index. Results revealed that Kamal cultivar is tolerant to cold and drought stresses, with suitable earliness, and good bread quality but susceptible to yellow rust and leaf rust, this xultivar way and released in 2019 under the name of Kamal for cold and moderate cold dry areas of Iran.

The new durum wheat cultivar, Sana (line DM-93-8) was initially introduced as a breeding line through 43rd International Durum Screening Nursery (IDSN) received from the International Maize and Wheat Improvement Center (CYMMIT) and was evaluated in Seed and Plant Improvement Institute (SPII) in Karaj. Sana was selected for further evaluations based on its high grain yield (7750 kgha-1) at the subsequent years. This line had average grain yield of 9675 kgha-1 in the regional preliminary yield trial in 2012-2013 cropping season. Line DM-93-8 had average grain yield of 6827 kgha-1 in the advanced yield trial, with no considerable difference with Dena check cultivar having grain yield of 6973 kgha-1 in 2013-2014, therefore this line was selected for the further evaluations. The regional elite yield trials were conducted in four stations of Isfahan, Karaj, Kermanshah and Neishabour in 2014-15 and 2015-16.  This line with 9025 kgha-1 had 16% higher grain yield than Dena check cultivar, with grain yield of 7779 kgha-1, and therefore was selected as superior line based on its grain yield and yield stability. Sana also has high quality of semolina, high protein content (12.2%) and high percentage of wet gluten (27%). The results of on-farm trials showed that this cultivar exhibited a 6% higher grain yield than newly released variety, Hana, as a local check in Kermanshah. Therefore, based on its high grain yield, yield stability, quality of semolina and its good level of resistance to yellow and leaf rusts, line DM-93-8 was released as a new durum wheat cultivar with the name of Sana for moderate agro-climate zone of Iran.

In order to produce wheat lines with high tolerance to drought and cold stresses, Sadra variety was generated by a cross between Sardari (male) and promising line Azadi/Azar (female) in Maragheh research station. Results of studies in the cold and moderate cold research stations showed that the grain yield means of Sadra, Azar2 and Sardari cultivars were 2394, 2332 and 2214 kgha-1, respectively, so that grain yield of Sadra was 8% and 3% higher than Sardari and Azar2 check cultivars, respectively. Sadra has a good adaptability to different climatic conditions, so that the new cultivar possess a great potential to be more productive during years with higher precipitation. According to the results, the mean grain yield of Sadra, Azar 2 and Sardari cultivars under optimal rainfall conditions were 3330, 3045 and 2522 kgha-1, respectively. Sadra cultivar has good general adaptability and grain yield stability, winter growth habit, high tolerance to cold and drought stresses, date to heading of 137 days, plant height of 80 cm and 1000 kernel weight of 35 gr. One of the most important characteristics of Sadra is its bread-making quality, so that Sadra with Zeleni number of 33, protein content of 11.3%, hardness of 47, wet gluten content of 30, gluten index of 50 and SDS sedimentation volume of 55 has a great bread-making quality. Based on its high yield potential and other appropriate agronomic characteristics, Sadra cultivar was released for cultivation in the cold and moderate cold dryland conditions of Iran.

"Khalil" wheat variety with the pedigree of Bow"s"/Vee"s"//1-60-3/3/Cocoraque 75/4/Chamran has derived from national wheat breeding program. The cross of this variety was made in Karaj in 2003-04 cropping season and then from F2 generation in 2005-06 cropping season, its segregating lines were studied through a shuttle breeding program between Iranshahr and Kelardasht research stations. The new variety was evaluated in Elite Regional Wheat Yield Trial (ERWYT) in the southern warm and dry zones' research stations during 2012-14 cropping seasons. The results confirmed that this new variety has yield stability in the studied research stations in southern warm and dry agro-climatic zone. Considering high grain yield, high level of resistance to different physiological races of stripe rust in different locations (hot spots), good grain quality as well as good agronomic performance and resistance to shattering, this line was selected and officially released as Khalil in 2017. Khalil, is adapted to irrigated wheat growing areas in the southern dry and warm agro-climatic zone in Iran, where in most of these regions a high disease pressure especially occurred by yellow rust is a limited factor for wheat production.

Release of new wheat cultivars with good characteristics such as high yield performance and resistance to diseases for specific regions under rainfed condition is an essential task for sustainability of wheat production. Saein was generated by crossing between: Azar2 and 87Zhong291 (with facultative growth type, high yield performance, good thousand kernel weight and resistance to diseases) in 1999-2000 in Maragheh Research Station. Grain yield means of Saein and Azar2 (as check cultivar) during 2006-2013 cropping seasons in Maragheh Research Station were 2601 and 2493 kgha-1 under rainfed condition and 3529 and 3223 kgha-1 with a supplementary irrigation at the sowing time, respectively. Results showed that Saein had also a specific adaptability in Ardabil regions and grain yield means of Saein (new cultivar), Ohadi and Azar2 (as check cultivars) in Ardabil were 1604, 1267 and 1355 kgha-1, respectively. Results of an on-farm study, in the farmer field in Ardabil province, showed that grain yield means of Saein and Azar2 during 2013-2014 cropping season were 2307 and 2275 kgha-1, respectively. The new cultivar is resistant to yellow rust, resistant to moderately resistant to leaf rust and also resistant to common bunt and dwarf bunt as well as resistant to cold damage, lodging and seed shuttering. New cultivar has winter growth type, white grain color, 76 cm plant height and 33 gr 1000 kernel weight. Based on its good characteristics, this line was released as a new wheat cultivar with the commercial name of Saein in 2015 and was recommended for cultivation in rainfed regions in Ardabil province, in the cold dryland areas in the north west of Iran and also in areas with the potential of supplementary irrigation.

Stem or black rust caused by Puccinia graminis f. sp. tritici (Pgt) is one of the most destructive wheat diseases in the world, including Iran. Investigation of virulence factors on wheat resistance genes, identification of resistance sources to stem rust among host genotypes and determination of effective resistance genes in resistant wheat genotypes are the requirements of using genetic resistance (production of resistant cultivars) as the most efficient and healthy way to control this disease. To assess the seedling resistance of 30 wheat genotypes, which produced CIMMYT Center (International Maize and Wheat Improvement Center), and introduced as resistance sources to stem rust was investigated with six different Pgt races base on randomized complete block design with three replications. Race analysis of Pgt isolates was done to identify of their virulence on resistance genes (Sr) of stem rust at the greenhouses of the cereal section of the Seed and Plant Improvement Institute. The results indicated that the races were TKTTF, TTTTF, PKSTC, TTRTF, TKSTF and PTRTF. Genotypes carrying the genes Sr22, Sr24, Sr26, Sr31, Sr32, Sr33 and Sr40 were resistance against all the Pgt races, and are introduced as the differential cultivars with effective Sr resistance genes. Genetic resistance components including infection type and latent period for each genotype were recorded under greenhouse conditions. The results of the genetic resistance components showed the existence of phenotypic variation in the response of genotypes to stem rust races. Resistant genotypes identified in this study (genotypes 4, 5, 6, 7, 8, 9, 11, 13, 14, 16, 17, 18, 20, 21, 22, 25, 26, 27, 28 and 29) can be used as seedling resistance resources in national wheat breeding programs for genetic resistance to stem rust in different climates of the country.

About 250,000 hectares of warm dryland regions have moderate to low rainfall, high temperatures and poor soil fertility with low production potential. Wheat cultivars which are currently used by farmers in these harsh environments, have low production in many years or they cannot be harvested due to their short plant's height or shriveled grains. Aseman cultivar with pedigree of KABY/3/TEVEE2/URES//FUN/KAUZ was generated by using the compatible parents at Gachsaran Agricultural Research Station in 2005-2006 cropping season. After a six-year period evaluation of the genetic material in the segregating populations, Aseman along with other selected pure lines were selected for further investigation through preliminary, advanced, and elite regional yield trails for four consecutive cropping seasons. In these experiments, average grain yield of new cultivar in Gachsaran and Behbahan stations, as well as in low-yield farms located in Golestan (Agh Ghala), Bushehr (Deilam) and Khuzestan (Haftakel) provinces was 2894 kgha-1, showing 3% superiority to Karim as the check cultivar. The average grain yield of Aseman in uniform regional trials was 2737 kgha-1 and it had a significant difference (p < /em> < 0.01) with Chamran (21% superiority) in the Gachsaran and Agh Ghala )for two years), as well as Behbahan, Haftkhel and Deilam (for one year) stations. Under severe drought and heat stresses in Deilam, Behbahan and Haftakel stations, the mean grain yield of the new cultivar increased by 37% and 10% compared to the Chamran and Karim cultivars, respectively. Early maturity, taller height and appropriate seed weight, especially under severe heat and drought stresses conditions and also superior baking quality are prominent characteristics of Aseman cultivar. These characteristics justify the importance of introducing this new cultivar for cultivation in the low-yield warm dryland regions of Iran.

The new durum wheat cultivar Aran (DW-91-6) was initially introduced as a breeding line through 41th International Durum Yield Nursery (IDYN) received from the International Maize and Wheat Improvement Center (CYMMIT) and was evaluated in two research stations of Khorramabad and Darab in warm agro-climate zone of Iran. In this step, Aran was selected for the further studies based on its high grain yield (6398 kgha-1). This line had average grain yield of 7183 kgha-1 in the regional preliminary yield trial in 2010-2011 cropping season. Line DW-91-6 had average grain yield of 7172 kgha-1 in the advanced yield trial compared to Behrang check cultivar with grain yield of 7068 kgha-1 in 2011-2012 cropping season and was selected for the further evaluations. In the regional elite yield trial conducted in four stations of Ahvaz, Darab, Dezful and Khorramabad in 2012-13 and 2013-14, this line with 7660 kgha-1 had 9% higher yield than Behrang check cultivar with grain yield of 7021 kgha-1 and was selected as superior line based on its grain yield and yield stability. Aran also has high quality of semolina, high protein content (13.6%) and high percentage of wet gluten (30%). The results of on-farm trials showed that this cultivar exhibited a 24% to 26% higher grain than Yavarus as a local check inKerman as well as a 17% higher grain yield compared to Behrang as a local check in Khoozestan. In total, based on its high grain yield, yield stability, quality of semolina and its good level of resistance to yellow and leaf rust diseases, line DW-91-6 was released as a new durum wheat cultivar with the name “Aran” for warm agro-climate zone of Iran.