Tritipyrum (2n=6x=42; AABBEbEb) is a new synthetic allohexaploid created through crossing durum wheat (2n=4x=28; AABB) and Thinopyrum bessarabicum (2n=2x=14; EbEb) and subsequently doubling the hybrid plant chromosomes. Secondary Tritipyrum is referred to the progenies of wheat and Tritipyrum crosses, obtained during segregating generations. The study of chromosomal constitution and fertility is very important in the assessment of hybrids derived fi:om wheat and wild relative crosses. Navid cuItivar of bread wheat (AABBDD; 2n=6x=42) was crossed with Tritipyrum (AABBEbEb; 2n=6x=42) the FI progenies being produced. F2 seeds were obtained by selfmg Fl plants and their chromosome number determined. The F2 plants possessing 42 chromosomes were selected for the study of their meiotic behavior. In spite of high chromosomal stability and fertility of the parents (wheat and Tritipyrum), these characteristics in F2 plants were observed as low probably due to the different chromosomal compositions and a lack of chromosome homology of D and Eb genomes and consequently the formation of univalents in pollen mother cells of F2 plants. The results of meiotic analysis of F2 plants confirmed the accessibility of different chromosomal composition and the production of either the addition or substitution lines in the progenies of segregating generations.

The genomic in situ hybridization (GISH) has been used to identify euploidy and aneuploidy in segregation generations of various plants. In this study, the GISH with minor modifications including, slide preparation of putative secondary Tritipyrum (F2) root meristemic cells, labeled genomic DNA of Thinopyrum bessarabicum by fluorescein 12-dUTP nucleotide as probe, genomic DNA of Thinopyrum bessarabicum for in situ hybridization on root meristemic cells of F2 (2n=6x=42, AABBDEb) and unlabeled Chinese Spring cultivar in pre hybridization, was carried out for the first time in Iran. The results not only indicated the various Eb chromosomes in putative 6x secondary Tritipyrum plants, but also showed different numbers of A, B and D chromosomes. The range of aneuoploidy in F2 genotypes was from %30 to %66.7, which could be due to various numbers of Eb and D chromosomes in each genotype. The selfing or back crossing of F2 plants with bread wheat varieties could lead to chromosomal stability and aneoploidy reduction in secondary Tritipyrum genotypes.

To evaluate drought tolerance in bread wheat, tritipyrum and triticale genotypes, 27 different genotypes were grown as a randomized complete block design under two irrigation regimes (control and drought) in two locations (Isfahan and Shiraz) during two growing seasons (2016 and 2017). Based on grain yield, several indices including stress tolerance index (STI), tolerance index (TOL), susceptibility index (SSI), mean productivity index (MP), geometric mean productivity index (GMP), drought sensitivity index (SDI), drought index (RDI), stress susceptibility percentage index (SSPI), Harmonic mean index (HARM) and Yield stability index (YSI) were calculated. According to the results of genotypes ranking in Isfahan region, triticale lines had the highest values of MP, GMP and STI indices over two years of study. In Shiraz region, triticale lines (4115 and 4116) had the highest values for drought tolerance indices. According to SSI and TOL indices, (triticale) and wheat genotypes (Bam, Omid and Alvand) were evaluated as drought tolerant genotypes in Isfahan region and Alvand and KaCr4 genotypes in Shiraz region in two years of evaluation. According to the correlation analyses, MP, GMP, HARM and STI indices had a positive and high correlation with grain yield in both stress and non-stress environments in both Isfahan and Shiraz regions. Superior-tolerant genotypes can be used in breeding programs to increase drought tolerance in future.

Wheat, although moderately tolerant to salt, can not be cultivated in many areas. However, in the triticeae tribe, some of the wild wheat relatives are highly tolerant, e.g. Thinopyrum bessarabicum, which grows on the sea shore. Eight primary hexaploid tritipyrum lines, amphiploids between Triticum durum and Thinopyrum bessarabicum have been produced which can set seed in at least 250 mM NaCl. These tritipyrums (2n=6x=42, AABBEbEb) due to reasons such as brittle rachis, continuous production of tillers, late maturity, tall stature and meiotic instability will not fulfill the requirements of a successful commercial salt tolerant crop. To overcome such problems the substituted tritipyrum, in which selected Eb chromosomes are replaced by D genome chromosomes of 6x wheat, was produced from 6x tritipyrum x 6x wheat hybrids (F1: 2n=6x=42, AABBDEb) followed by selfing and backcrossing with 6x tritipyrum. The fertile plants among the above progenies were screened by the genomic fluorescent in situ hybridization technique to identify their Eb and D chromosome constitution. This study showed that producing tritiprum with variable numbers of Eb and D genome chromosomes is feasible and that FISH is a useful technique for determining the number of Eb chromosomes present.

Soil affected by salt (NaCl) is a major problem worldwide and in areas with potential agriculture; lands in many countries are not enough to support crop production. The development of salt tolerant cultivars would be enhanced by better understanding of the genetic control of tolerance to salt stress. A new cereal, tritipyrum, a range of amphiploids between Triticum spp. and Thinopyrum spp. offers such a new chance. Those with the 6x construction (2n=6x=42, AABBEbEb) derived from Triticum durum (2n=4x=28, AABB) and Thinopyrum bessarabicum (2n=2x=14, EbEb) are of the potential to become a new high salt tolerant cereal crop. Tritipyrum is prone to problems similar to those exhibited by early triticales, e.g. chromosome instability and low fertility, which in that crop were eventually overcome by breeding. Other problems could be overcome through substitution of Eb genome chromosomes by D genome ones and the feasibility of this have been assessed in the progenies of (6x tritipyrum) x (6x wheat) hybrids with the aid of fluorescent in situ hybridization (FISH). The cytological, morphological and agronomic studies of existing tritipyrum lines, including the effect of vernalization, were carried out, too. A novel multiple- pistil/seed characteristic of one original tritipyrum line has also been investigated and its genetic basis established. The results have shown that, first creation of substituted lines is feasible, and thus it could be a route for the elimination of undesirable traits. Second, improvement should be possible via selection for chromosomally stable lines, with increased fertility and yield. Third, it may also be possible to exploit the perennial habit and multi-tillering traits in a dual-purpose forage/grain crop. Fourth, the multiple-pistil/seed trait may be controlled by two recessive genes. Fifth, there is a high probability of having established the seven possible monosomic additions of Th. bessarabicum to T.durum for the first time.

Synthetic plants as well as wild crop species are valuable genetic resourses. To determine the genetic variation in triticale, tritipyrum as well as wheat lines, genomic DNA of this amphiploid including Thinopyrum bessarabicum and durum wheat were amplified using 32 random and 22 semi random primers. Primers that could produce clear, polymorphic and repetitive bands are used for determination of similarity matrix and dendogram based on Jaccard similarity coefficients and UPGMA algorithm. The similarity coefficients were in the range of 0.01-0.55, 0.02-0.63 and 0.04-0.53 for random, semi-random and a combination of random and semi-random primers, respectively, indicating a broad genetic divergence among these three amphiploids, durum wheat andTh. bessarabicum. For the combination of random and semi-random primers, average genetic similarity between triticale premising lines, tritipyrum primary lines, andTh. bessarabicum were found to be 0.179, between tritipyrum primary lines and wheat breeding cultivars 0.194 and between triticale premising lines and wheat breeding cultivars 0.161. Steward tetraploid wheat exhibits the highest genetic distance from 4103 triticale line. The triticale lines 4103 and 4116 exhibited the lowest genetic distance between each other. La (4B) 4D/b tritipyrum line has the highest genetic similarity with chains spring wheat cultivar. St/b and Cr/b tritipyrum lines had the highest genetic similarity with the paternal line (Thinopyrum bessarabicum). This study confirms the efficiency of semi-random than random primers, as well as the combination of random and semi-random primers than their sporadics in an estimation of genetic diversity.

In order to determine genetic relative between triticale, tritipyrum and wheat genomes, genomic DNA of Thinopyrum bessarabicum (EbEb), triticale premising lines (AABBRR), tritipyrum primary lines (AABBEbEb), Chinese spring and breeding cultivars of wheat (AABBDD) were amplified using 25 semi random and 30 random primers. Bands that present in the Th. Bessarabicum, triticale premising lines and tritipyrum lines, but absent in the breeding and Chinese spring cultivars of wheat, assumed as shared bands between triticale (RR) and tritipyrum (EbEb) genomes. Jaccard coefficient of similarity used for determination of genetic relative of triticale (RR) and tritipyrum (EbEb) with wheat genomes. ET34 and ET37 of semi random and OPM06 of random primers could be amplified shared bands between triticale (RR) and tritipyrum (EbEb) genomes. From 238 bands that amplified by random and semirandom primers, 5 bands (2.2%) were shared between triticale (RR) and tritipyrum (EbEb) and 16.8% were shared between tritipyrum (EbEb) and wheat genomes. 4.02% of RAPD markers, were specified to tritipyrum (EbEb) genome. Average genetic similarity between triticale premising lines, tritipyrum primary lines, and Th. bessarabicum were 0.179, between tritipyrum primary lines and wheat breeding cultivars were 0.194 and between triticale premising lines and wheat breeding cultivars were 0.161. This study confirmed high homology of tritipyrum (EbEb) with wheat, relatively homology of triticale (RR) and tritipyrum (EbEb) genomes and usefulness of random and semi random primers in detecting chromatin/DNA fragment of intergeneric hybrids with durum wheat.