GENOMIC IN SITU HYBRIDIZATION (GISH) OF NATURAL TRIPLOID LOQUAT SEEDLINGS

Genome in situ hybridization (GISH) was applied to identify the origin of natural triploid loquat seedlings derived from 12 cultivars using the genomic DNA of the seed parent as the probe. The presence of greenish yellow signals on the chromosomes indicated two different results: (1) in most cases signals were distributed equally on all 51 chromosomes of triploids; (2) in a few cases signals only on 34 chromosomes with the remaining 17 chromosomes displaying weak and uncharacteristic signals. These results suggest that the natural triploid loquat seedlings originated from unreduced gametes in the seed parent with the haploid gamete coming from either the same genotype of the seed parent (homogenous triploids resulting from self pollination) or a gamete from a different cultivar (heterogenous triploids resulting from cross pollination).