Articles
DEVELOPMENT OF GENETIC MARKERS TO IDENTIFY TWO ASPARAGUS CULTIVARS
Article number
415_19
Pages
129 – 136
Language
Abstract
Asparagus cultivars are difficult to identify because many differ only in performance characters that are influenced by climate and soil type.
We have been particularly concerned with methods for identification of ‘UC 157’ and ‘Ida Lea’, clonal-hybrid cultivars developed and patented by the University of California.
In order to distinguish F1 seed of these two cultivars from F2 or open-pollinated seed of these or other cultivars, we wish to identify molecular markers that are homozygous for different alleles in the parental clones of each cultivar.
Initial studies with isozymes and RFLPs (restriction fragment length polymorphisms) detected with random genomic probes did not reveal any suitable markers, and indicated that the parental genotypes were highly homozygous and genetically very similar.
We then screened for RAPD (random amplified polymorphic DNA) variation among the parental clones using 60 random decamer primers.
Repeatable polymorphisms were amplified with 9 primers in one or both families.
Parental and F1 phenotypes were consistent with dominant inheritance for all of these polymorphisms.
Eleven amplified segments, including those showing polymorphism, were excised from the gels and used as probes on Southern blots of parental and F1 hybrid DNA. Ten amplified segments hybridized to one or a few genomic DNA fragments, and four of these probes detected polymorphisms.
For two of these polymorphisms, the parents of ‘UC 157’ had different restriction fragments that were both present in the F1. One of these RAPD products was cloned and when used as a probe, it hybridized to a codominant RFLP on Southern blots of UC 157 F2 progeny.
To convert this marker to a SCAR (sequence characterized amplified region), the clone was sequenced and specific PCR primers were synthesized.
The product amplified by these primers was monomorphic in the UC 157 family, and digestions with 10 restriction endonucleases did not reveal any polymorphism.
No suitable markers for ‘Ida Lea’ were identified.
The RAPD and RFLP markers are suitable for distinguishing F1 from F2 seed of UC 157 and for evaluating seed purity.
We have been particularly concerned with methods for identification of ‘UC 157’ and ‘Ida Lea’, clonal-hybrid cultivars developed and patented by the University of California.
In order to distinguish F1 seed of these two cultivars from F2 or open-pollinated seed of these or other cultivars, we wish to identify molecular markers that are homozygous for different alleles in the parental clones of each cultivar.
Initial studies with isozymes and RFLPs (restriction fragment length polymorphisms) detected with random genomic probes did not reveal any suitable markers, and indicated that the parental genotypes were highly homozygous and genetically very similar.
We then screened for RAPD (random amplified polymorphic DNA) variation among the parental clones using 60 random decamer primers.
Repeatable polymorphisms were amplified with 9 primers in one or both families.
Parental and F1 phenotypes were consistent with dominant inheritance for all of these polymorphisms.
Eleven amplified segments, including those showing polymorphism, were excised from the gels and used as probes on Southern blots of parental and F1 hybrid DNA. Ten amplified segments hybridized to one or a few genomic DNA fragments, and four of these probes detected polymorphisms.
For two of these polymorphisms, the parents of ‘UC 157’ had different restriction fragments that were both present in the F1. One of these RAPD products was cloned and when used as a probe, it hybridized to a codominant RFLP on Southern blots of UC 157 F2 progeny.
To convert this marker to a SCAR (sequence characterized amplified region), the clone was sequenced and specific PCR primers were synthesized.
The product amplified by these primers was monomorphic in the UC 157 family, and digestions with 10 restriction endonucleases did not reveal any polymorphism.
No suitable markers for ‘Ida Lea’ were identified.
The RAPD and RFLP markers are suitable for distinguishing F1 from F2 seed of UC 157 and for evaluating seed purity.
Publication
Authors
M.L. Roose, N.K. Stone
Keywords
Online Articles (67)