The findings could help growers select the most productive olive varieties. Next, they plan to look for genes associated with polyphenol production.
The researchers extracted DNA from the 50 specimens using a genome-wide association study analysis, which they said was similar to “reading” and assembling DNA as if it were a detailed instruction manual.
Researchers in Spain have identified nine genes that they said showed a “high statistically significant correlation” with fruit weight.
Historically, fruit weight was the most significant trait sought by farmers when identifying which wild olive cultivars to domesticate, along with oil content and ability to grow in anthropogenic environments.
“Larger fruit size is extremely important in cultivated olive trees to facilitate harvesting,” researchers from the University of Jaén and the Institute of Agricultural and Fisheries Research and Training (Ifapa) wrote in the study published in Plants.
“Therefore, fruit size in traditional olive cultivars is much bigger than in wild ones,” they added. “However, as the long juvenile period is a main hindrance in classic breeding approaches, obtaining genetic markers to be used in breeding programs for this trait is a highly desirable tool.”
According to the researchers, this was the first study identifying individual genes linked with olive weight. The Discover Foundation, an Andalusian government research support group that funded the study, hailed the findings as a significant advancement in understanding the genetics of olive fruit development.
The researchers used data from the genomes of 40 cultivated olive varieties and ten wild olive tree species, which they had previously sequenced, selecting representative samples of each variety with olives of different weights.
They said the 40 cultivated olive varieties represent more than 90 percent of the genetic variability of domesticated olive tree varieties. They added that the ten wild varieties sequenced represented a broad geographical sample of non-domesticated olive trees. More