Establishment of introgression libraries in hybrid rye (Secale cereale L.) from an Iranian primitive accession as a new tool for rye breeding and genomics.

Genetic diversity of elite breeding material can be increased by introgression of exotic germplasm to ensure long-term selection response. The objective of our study was to develop and characterize the first two rye introgression libraries generated by marker-assisted backcrossing and demonstrate their potential application for improving the baking quality of rye. Starting from a cross between inbred line L2053-N (recurrent parent) and a heterozygous Iranian primitive population Altevogt 14160 (donor) two backcross (BC) and three selfing generations were performed to establish introgression libraries A and B. Amplified fragment length polymorphisms (AFLP markers) and simple sequences repeats (SSRs) were employed to select and characterize candidate introgression lines (pre-ILs) from BC(1) to BC2S3. The two introgression libraries comprise each 40 BC2S3 pre-ILs. For analyzing the phenotypic effects of the exotic donor chromosome segment (DCS) we evaluated the per se performance for pentosan and starch content in replicated field trials at each of four locations in 2005 and 2006. Introgression library A and B cover 74 and 59% of the total donor genome, respectively. The pre-ILs contained mostly two to four homozygous DCS, with a mean length of 12.9 cM (A) and 10.0 cM (B). We detected eight (A) and nine (B) pre-ILs with a significant (P<0.05) higher pentosan content and two pre-ILs (B) with a significant (P<0.05) higher starch content than the elite recurrent parent. Thus, our results indicate that exotic genetic resources in rye carry favorable alleles for baking quality traits, which can be exploited for improving the elite breeding material by marker-assisted selection (MAS). These introgression libraries can substantially foster rye breeding programs and provide a promising opportunity to proceed towards functional genomics.