Self-incompatibility genotypes in almond re-evaluated by PCR, stylar ribonucleases, sequencing analysis and controlled pollinations.
As part of the almond breeding programme at IRTA, we investigated the S genotypes of several cultivars using a combination of RNase zymograms, testcrosses, pollen-tube growth analysis and molecular identification by PCR analysis. For some of the cultivars examined, discrepancies appeared between their S alleles as reported in the literature and those found in this investigation, leading to a re-evaluation of their S genotypes. Analysis of the stylar ribonucleases (RNases), which are known to correlate with S alleles, of cvs. Achaak, Ardechoise, Desmayo Largueta, Ferrastar, Gabaix, Garbi, Glorieta, Languedoc, Primorskiy and Texas revealed inconsistencies with respect to the S5 and S10 alleles. However, PCR with the conserved primer pair AS1II/AmyC5R failed to detect any of these inconsistencies. When the S alleles from Desmayo Largueta, Gabaix, Primorskiy and Texas were sequenced, Texas and Primorskiy were found to carry the reported S5 allele, while Desmayo Largueta and Gabaix carried a new allele, which has been tentatively denoted as S25 This new S allele, previously reported to be S10, was also identified in Achaak, Ardechoise and Ferrastar. The proposed new S genotypes are Achaak (S2S25), Ardechoise (S1S25), Desmayo Largueta (S1S25), Ferrastar (S2S25) and Gabaix (S10S25). The S alleles of Garbi, Glorieta, Languedoc, Texas and Primorskiy remain as reported in the literature. Testcrosses in the field and laboratory confirmed the new S genotypes. One cultivar (Gabaix) could be assigned to the existing cross-incompatibility group O of unique genotypes, and two new groups were established (XVI and XVII) consisting of two cultivars each. The clarification of these S alleles will be useful in almond breeding programmes and for planning new commercial orchards in the future.
López
Mercè
M
Departament d'Arboricultura Mediterrània, IRTA-Centre de Mas Bové, Ap. 415, 43280, Reus-Tarragona, Spain.
Mnejja
Mourad
M
Rovira
Mercè
M
Collins
Graham
G
Vargas
Francisco J
FJ
Arús
Pere
P
Batlle
Ignasi
I
D000483:Alleles; D001483:Base Sequence; D001947:Breeding / Q000379:methods; D016000:Cluster Analysis; D017931:DNA Primers; D005838:Genotype; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D027861:Prunus / Q000235:genetics* / Q000254:growth & development; D012098:Reproduction / Q000235:genetics; D012260:Ribonucleases / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D017931:DNA Primers; D012260:Ribonucleases