Genetic\ agronomic and quality comparisons of two 0AL[0RS[ wheatÐrye chromosomal translocations

The 0AL[0RS wheatÐrye chromosomal translocation originally found in {Amigo| wheat possesses resistance genes for stem rust\ powdery mildew and greenbug biotypes B and C\ but also has a negative e}ect on wheat processing quality[ Recently\ a second 0AL[0RS translocation carrying Gb5\ a gene conferring resistance to greenbug biotypes B\ C\ E\ G and I\ was identi_ed in the wheat germplasm line {GRS0190|[ Protein analytical methods\ and the DNA polymerase chain reaction were used to identify markers capable of di}erentiating the 0RS chro! mosome arms derived from {Amigo| and {GRS0190|[ The secalin pro! teins encoded by genes on 0RS chromosome arms di}ered in {Amigo| and {GRS0190|[ A 69 kDa secalin was found in the {Amigo| 0AL[0RS\ but did not occur in the {GRS0190| 0AL[0RS[ Polymorphisms detected by PCR primers derived from a family of moderately repetitive rye DNA sequences also di}erentiated the two translocations[ When {GRS0190| was mated with a non!0RS wheat\ no recombinants between 0RS markers were observed[ In crosses between 0RS and non!0RS parents\ both DNA markers and secalins would be useful as selectable markers for 0RS!derived greenbug resistance[ Recombination between 0RS markers did occur when 0RS from {Amigo| and 0RS from {GRS0190| were combined\ but in such intermatings\ the molecular markers described herein could still be used to develop a population enriched in lines carrying Gb5[ No di}erences in grain yield or grain and ~our quality characteristics were observed when lines carrying 0RS from {Amigo| were compared with lines with 0RS from {GRS0190|[ Hence\ di}erences in secalin composition did not result in di}erential quality e}ects[ When compared with sister lines with 0AL[0AS derived from the wheat cultivar {Redland|\ lines with {GRS0190| had equal grain yield\ but produced ~ours with signi_cantly shorter mix times\ weaker doughs\ and lower sodium dodecyl sulphate sedimentation vol! umes[ Key words] Secale cereale * Triticum aestivum * agronomic and quality e}ects * chromosomal translocation * greenbug resistance * markers * rye * wheat Translocations of rye\ Secale cereale L[\ chromatin into the wheat\ Triticum aestivum L[\ genome have been used in wheat breeding programmes to introduce genes of agronomic import! ance[ The 0BL[0RS translocation derived from the Russian cultivar {Kavkaz|\ possesses resistance genes for major wheat diseases such as stem\ stripe and leaf rusts\ and powdery mildew "Mettin et al[ 0862\ Zeller 0862#\ while the 0AL[0RS trans! location\ derived from {Amigo|\ carries genes for stem rust\ powdery mildew\ and greenbug resistance "Zeller and Hsam 0873#[ The {Amigo|!derived 0AL[0RS translocation has been more successful in the Great Plains of North America than in U[ S[ Copyright Clearance Center Code Statement] 9068Ð8430:88:0791Ð9014 , 03[99:9 other parts of the world[ 0AL[0RS cultivars\ including {TAM096|\ {TAM199|\ {TAM191| and {Century| have been registered from several US wheat breeding programmes\ and occupy signi_cant production acres\ especially in the semi!arid western edges of hard winter wheat cultivation[ Recently\ {GRS0190|\ a wheat germplasm line with resistance to greenbug biotypes B\ C\ E and G\ was developed by Porter et al[ "0880#[ The greenbug resistance allele in {GRS0190| was designated Gb5[ Porter et al[ "0883#\ using C!banding\ found {GRS0190| to carry a 0AL[0RS wheatÐrye translocation and described it as being cytologically indistinguishable from the {Amigo| 0AL[0RS[ {GRS0190| di}ers signi_cantly from {Amigo|!derived 0AL[0RS lines in terms of greenbug biotype! speci_c resistance\ even though both were derived from {Insave| rye[ {Amigo|!derived 0AL[0RS lines carry Gb1 and are resistant to greenbug biotypes B and C\ but susceptible to biotypes E and G "Porter et al[ 0880#[ Since rye is cross! pollinated and genetic heterogeneity within cultivars and accessions is extensive\ such di}erences among 0AL[0RS lines are likely[ Markers capable of di}erentiating these trans! locations would be quite useful since the identi_cation of green! bug race resistance can be di.cult[ In at least some genetic backgrounds\ 0BL[0RS trans! locations appear to increase grain yield and environmental sta! bility for yield "Lukaszewski 0889\ Villareal et al[ 0880\ Moreno! Sevilla et al[ 0884#[ Espitia!Rangel et al[ "0887a# found no di}erence in grain yield in 0AL[0RS "{Amigo|!derived# and 0AL[0AS sister lines selected from the heterogeneous cultivar {Nekota|\ although the 0AL[0RS lines had signi_cantly heavier seeds in stressful environments[ 0AL[0RS "{Amigo|!derived# lines had higher ~our protein content but lower mixograph times and tolerances\ than their 0AL[0AS sibs[ The objectives of this study were to distinguish the {GRS0190| 0AL[0RS trans! location from the {Amigo| 0AL[0RS translocation using either DNA oligonucleotide primers and the polymerase chain reac! tion "PCR# and:or analysis of prolamines "seed storage proteins soluble in 69) ethanol#\ to determine whether such markers would be useful in the selection of new breeding lines with desired greenbug resistance alleles\ and to determine whether any grain yield or quality e}ects could be attributed to the presence of the {GRS0190|!derived 0AL[0RS translocation[ Materials and Methods The following parental lines were used] {Redland|\ a non!0RS greenbug susceptible hard red winter wheat cultivar\ {TAM191|\ a hard red winter 015 GRAYBOSCH\ LEE\ PETERSON\ PORTER and CHUNG wheat carrying the {Amigo| 0AL[0RS translocation\ and {GRS0190|[ Each of the 0RS wheats was crossed to {Redland|\ and {GRS0190| and {TAM191| were intermated[ Crosses were made in the greenhouse in the spring of 0881^ F0 seed was fall!sown in Yuma\ AZ\ USA\ in 0881[ In 0882\ F1 populations were grown in the greenhouse at Lincoln\ NE\ USA[ F2 seed was harvested from each F1 plant separately[ A 09!mg sample was removed from the brush end of 09 randomly selected F2 seeds from each F1 plant[ Samples were pooled for analysis[ Prolamines were extracted with 69) ethanol\ separated on 00) sodium dodecyl sulphate "SDS#Ðpolyacrylamide gels and silver!stained "Graybosch and Morris 0889#[ Rye prolamines "secalins# were identi_ed by comparison with known 0RS wheats and through immunoblot analysis using a secalin!speci_c monoclonal antibody "Graybosch et al[