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Advisor(s)
Abstract(s)
Background. Cashew (Anacardium occidentale L.) is a crop currently grown in several
tropical countries because of the economic importance of cashew nuts. Despite its
enormous economic worth, limited research has been conducted on the molecular
diversity of cashew genetic resources. In this study, a wide comprehensive assessment of
the genetic diversity of cashew trees in East Timor was performed using microsatellites
(SSRs) to evaluate intraspecific diversity and population structuring.
Methods. A total of 207 individual cashew trees, including trees from East Timor
(11), and outgroup populations from Indonesia (one) and Mozambique (two), were
analyzed with 16 cashew-specific SSRs. A comprehensive sampling of cashew trees
within East Timor was performed, covering the distribution of cashew orchards in
the country. Genetic diversity indices were calculated, and population structuring was
determined using three different approaches: genetic distances (UPGMA and NJ),
AMOVA, and individual-based clustering methods through Bayesian (STRUCTURE)
and multivariate (DAPC) analyses.
Results. The population structuring analysis revealed that the genetic diversity of
cashew populations in East Timor was higher in this study than previously reported
for cashew trees. A higher allelic richness was found within cashew populations in
East Timor compared with the outgroup populations (Mozambique and Indonesia),
reinforced by the presence of private alleles. Moreover, our study showed that cashew
populations in East Timor are grouped into two dissimilar genetic groups, which may
suggest multiple cashew introductions over time. These new cashew genetic resources
could be explored for future crop improvement.
Conclusions. Crop diversity underpins the productivity, resilience, and adaptive
capacity of agriculture. Therefore, this study provides useful information regarding
genetic diversity and population structure that can be harnessed to improve cashew
production in East Timor. This data is also important to creating a country-specific
genetic cashew signature to increase cashew market value.
Description
Keywords
Genetic diversity SSRs Population structuring Southeast Asia Diversity hotspots
Pedagogical Context
Citation
e Guterres L, Barnabé J, Barros A, Charrua AB, Duarte MC, Romeiras MM, Monteiro F. 2023. East Timor as an important source of cashew (Anacardium occidentale L.) genetic diversity. PeerJ 11:e14894
Publisher
PeerJ