USE OF MARKERS FOR VARIETY IDENTIFICATION: CASE OF THE AMAZON HYBRID
The phenotype is the interaction of the genotype with the environment, so the variations associated with this last factor can generate uncertainty in the phenotypic identification of the varieties. The study of organisms using molecular biology tools such as molecular markers, allows identification of the genetic information without relying on the environment.
With the use of microsatellites, it was shown that OxG Amazon hybrid plants have a genetic load that is intermediate between their parents: oleiferas from Brazil and compact palms. This study definitely demonstrates the genetic authenticity of these hybrids.
A young palm (26 months in the field) of the OxG Amazon hybrid showing great precocity in Tumaco, Colombia.
In Figure 1, the distance from the origin of the axes indicates the proximity or distance of the genetic groups studied. Groups that fall in opposite directions are negatively correlated, as in the case of compact palms and oleifera palms from Brazil.
Using microsatellites, the DNA of the individual palms within each type was also analyzed to confirm the hybrid nature of the samples. The analysis of the main coordinates (Fig. 2) based on the genetic distance, reflected a clear separation of the compact palms, the Amazon hybrids and the oleiferas from Brazil located in the left, central and right sectors of Figure 2, respectively. The analysis determined that the genetic identity of the Amazon hybrids was 0.60 and 0.40 with the oleiferas from Brazil and the compact palms, respectively. This result approximates the proportion of the oleifera genome transmitted to the Amazon hybrid from its female Manaus oleifera and male compact progenitors.
When the RC1F2 compact germplasm (second generation of the first backcross to guineensis of the original compact palm) was used in the "analysis of grouped segregants", a closer approximation of the Amazon hybrids with oleiferas was observed because there is a higher proportion (56.25%) of the of E. oleifera genome. On the other hand, the analysis of individual palms showed an intermediate approach of the hybrids with the oleifera and compact types, since the latter belong to the RC2 (second backcross), where the oleifera genes are diluted to 53.125%.
The molecular study of the three types of palms in question allowed us to conclude that the samples collected from commercial Amazon hybrid plantations in Guapi, Colombia, truly correspond to a cross of Elaeis oleifera x Compact, and that these palms are genetically separated from both progenitors.
Fig. 1. Molecular markers shared between hybrid palms (Amazon) with compact palms and oleiferas from Brazil. Each numeral "1" represents a different molecular marker.
Fig. 2. Confirmation of the hybrid nature of the Amazon palm samples collected in Guapi (Colombia) through ‘principal coordinates analysis”