The Study of chromosome constitution in secondary Tritipyrum genotypes (F2) by genomic in situ hybridization technique (GISH)

To remove unfavorable traits of new cereal Tritipyrum (2n=6x=42, AABBE^bE^b), various crosses between primary Tritipyrum lines (female) with Iranian bread wheat varieties (2n=6x=42, AABBDD) was performed and a F2 selfing population consisted of 1810 possible secondary Tritipyrum seeds (2n=6x=42, AABBD(0-14) E^b(0-14)) were produced. The chromosome constitution and homology index of 11 plants of this F2 progeny was assessed by genomic in situ hybridization (GISH). The results indicated that 1) without using Chinese spring DNA as a blocker differentiation between A, B, D and E^b chromosomes was impossible, 2) Secondly differentiation between A, B, D and E^b informs of single or pairs (rod or ring) chromosomes was improved by adding the preblocking hybridization step, using Chinese spring genomic DNA as probe, to normal GISH protocol. Third the E^b chromosome counts in F2 plants showed the feasibility of selection of the so called secondary Tritipyrum genotypes (F2) with different number of D and E^b chromosomes for favorable agronomic traits by genomic in situ hybridization as a powerful cytogenetic assisted marker selection (CAMS).