ORIGIN OF ALMOND MULTIPLE EMBRYOS AND POTENTIAL UTILIZATION AS NEAR ISOGENIC LINES

Multiple embryos enclosed within the same seedcoat occur spontaneously in some almond cultivars.
Seedlings from polyembryonic seeds are usually viable, but sometimes one of the seedlings shows weak development.
These dwarf seedlings have been characterized as haploids or aneuploids.
In this study, 12 seedling pairs from polyembryonic seeds of ‘Nonpareil’ were analysed using 10 Simple Sequence Repeat (SSR) loci that are well dispersed over the whole genome.
Small differences between the SSR banding patterns of a dwarf seedling compared to the normal-phenotype seedling from the same seed, may indicate the loss or distortion of part of a chromosome (near isogenic lines) or a whole chromosome (monosomic aneuploidy). In our study, seedlings originating from the same seed but having dwarf and normal phenotypes, respectively, showed similar banding patterns in most cases, indicating that they constitute isogenic or near isogenic lines.
In one case, considerable banding pattern differences were found between the two seedlings in a pair, suggesting very different genotypes rather than isogenic lines or near isogenic lines.
Future studies with an increased number of seedlings and SSRs, together with a study of agronomical traits in the field, could be very useful to understand better the genetic nature of this phenomenon and the genetic control of agronomic traits in almond.

XI Eucarpia Symposium on Fruit Breeding and Genetics

R. Sánchez-Pérez, F. Dicenta, P. Martínez-Gómez, T.M. Gradziel

molecular markers, embryogenesis, Prunus dulcis, SSR

https://doi.org/10.17660/ActaHortic.2004.663.148