Linkage mapping of powdery mildew and greenbug resistance genes on recombinant 1RS from 'Amigo' and 'Kavkaz' wheat–rye translocations of chromosome 1RS.1AL

Abstract

Cultivated rye (Secale cereale L., 2n = 2x = 14, RR) is an important source of genes for insect and disease resistance in wheat (Triticum aestivum L., 2n = 6x = 42). Rye chromosome arm 1RS of S. cereale 'Kavkaz' originally found as a 1BL.1RS translocation, carries genes for disease resistance (e.g., Lr26, Sr31, Yr9, and Pm8), while 1RS of the S. cereale 'Amigo' translocation (1RSA) carries a single resistance gene for greenbug (Schizaphis graminum Rondani) biotypes B and C and also carries additional disease-resistance genes. The purpose of this research was to identify individual plants that were recombinant in the homologous region of.1AL.1RSV and 1AL.1RSA using both molecular and phenotypic markers. Secale cereale 'Nekota' (1AL.1RSA) and S. cereale 'Pavon 76' (1AL.1RSV) were mated and the F1 was backcrossed to 'Nekota' (1AL.1AS) to generate eighty BC1F2:3 families (i.e., ('Nekota' 1AL.1RSA x 'Pavon 76' 1AL.1RSV) x 'Nekota' 1AL.1AS). These families were genotyped using the secalin-gliadin grain storage protein banding pattern generated with polyacrylamide gel electrophoresis to discriminate 1AL.1AS/1AL.1RS heterozygotes from the 1AL.1RSA+V and 1AL.1AS homozygotes. Segregation of the secalin locus and PCR markers based on the R173 family of rye specific repeated DNA sequences demonstrated the presence of recombinant 1AL.1RSA+V families. Powdery mildew (Blumeria graminis) and greenbug resistance genes on the recombinant 1RSA+V arm were mapped in relation to the Sec-1 locus, 2 additional protein bands, 3 SSRs, and 13 RFLP markers. The resultant linkage map of 1RS spanned 82.4 cM with marker order and spacing showing reasonable agreement with previous maps of 1RS. Fifteen markers lie within a region of 29.7 cM next to the centromere, yet corresponded to just 36% of the overall map length. The map position of the RFLP marker probe mwg68 was 10.9 cM distal to the Sec-1 locus and 7.8 cM proximal to the powdery mildew resistance locus. The greenbug resistance gene was located 2.7 cM proximal to the Sec-1 locus.

Molecular Cytogenetic Characterization of Novel Wheat-rye T1RS.1BL Translocation Lines with High Resistance to Diseases and Great Agronomic Traits

“…Since the 1990s, due to its single origin, the 1RS chromosome arm derived from Petkus rye has not provided protection against the prevalence of virulent pathogens (Shi et al, 2001; Ren et al, 2009). So far, only a few other sources of 1RS were transferred into wheat (Ko et al, 2002; Mater et al, 2004; Ren et al, 2009, 2012; Molnár-Láng et al, 2010; Yang et al, 2014; Li et al, 2016a,b; Qi et al, 2016), and not every new translocation line could be used in wheat breeding programs (Ren et al, 2012). For more efficient use of the T1RS.1BL translocation in wheat breeding, Ren et al (2012) suggested introduce a large amount of new genetic variation from many different rye sources into wheat.…”

Molecular cytogenetic characterization of a new wheat-rye 1BL•1RS translocation line expressing superior stripe rust resistance and enhanced grain yield

“…Such genetic vulnerability was largely caused by wide deployment of 1BL•1RS translocations in which the 1RS chromosome arm was mainly from one variety, i.e., ''Petkus'' rye (Villareal et al 1998;Lelley et al 2004). So far, only a few sources of 1RS were the progenitors of 1BL•1RS translocation in wheat worldwide (Lukaszewski 1990;Kim et al 2004;Mater et al 2004;Ren et al 2009). Therefore, it is critical to search for and introduce new elite alien genes to increase the genetic diversity of common wheat by development of more 1BL•1RS translocations (Ren et al 2009).…”

Diversity resistance to Puccinia striiformis f. sp Tritici in rye chromosome arm 1RS expressed in wheat

“…Paldanghomil in Korea. A 1AL.1RS translocation cultivar, Amigo, which is derived from the 1RS arm of rye cultivar Insave, has been a source in some North American wheat cultivars due to its resistance against powdery mildew, greenbug, stem rust, and wheat curl mite (Zeller and Fuchs, 1983;Zeller and Hsam, 1983; Con-Diversity resistance to stripe rust in 1RS 10 ner et Rabinovich, 1998;Mater et al, 2004). Another 1AL.1RS translocation was selected in the 1990s (Porter et al, 1991(Porter et al, , 1994.…”