Identification of chromosome‐specific simple sequence repeat markers to characterize the Langdon durum D‐genome disomic substitution lines

Abstract Genetic studies of durum wheat ( Triticum turgidum L. ssp. durum [Desf.] Husnot.) provide valuable information for crop improvement. In the 1980s, D‐genome disomic chromosome substitution (DS) lines were developed, which involved the substitution of a pair of D‐genome chromosomes from hexaploid wheat ( T. aestivum L.) for a pair of homoeologous A‐ or B‐genome chromosomes in the durum variety Langdon (LDN). DS lines were developed for each of the durum chromosomes, and they have been used extensively over the past 35 years for genetic studies. However, true DS lines for five chromosomes were not obtained because the substituted chromosomes do not completely compensate for their homoeologous chromosomes. These non‐compensating DS lines are maintained with a monosome or telosome, which segregate in progeny and require cytogenetic analyses to determine the chromosome constitution of individual plants before evaluation. Here, our objective was to identify chromosome‐specific simple sequence repeat (SSR) markers that could be used to characterize the chromosome constitution of all 14 Langdon disomic substitution (LDN‐DS) lines. Toward this goal, we identified two to five SSRs specific to each chromosome that can be used to determine the chromosome constitution of each of the LDN‐DS lines using basic polymerase chain reaction and agarose gel electrophoresis. In the process, we found that the LDN‐4D(4A) substitution line has been lost and now exists only as a disomic chromosome 4D addition line. This work provides a simplified means for characterizing the LDN‐DS lines suitable for most laboratories, which will allow more researchers to use the LDN‐DS stocks for various genetic studies.