Abstract
The peanut (Arachis hypogaea) is an important oil crop. Breeding for high oil content is becoming increasingly important. Wild Arachis species have been reported to harbor genes for many valuable traits that may enable the improvement of cultivated Arachis hypogaea, such as resistance to pests and disease. However, only limited information is available on variation in oil content. In the present study, a collection of 72 wild Arachis accessions representing 19 species and 3 cultivated peanut accessions were genotyped using 136 genome-wide SSR markers and phenotyped for oil content over three growing seasons. The wild Arachis accessions showed abundant diversity across the 19 species. A. duranensis exhibited the highest diversity, with a Shannon-Weaver diversity index of 0.35. A total of 129 unique alleles were detected in the species studied. A. rigonii exhibited the largest number of unique alleles (75), indicating that this species is highly differentiated. AMOVA and genetic distance analyses confirmed the genetic differentiation between the wild Arachis species. The majority of SSR alleles were detected exclusively in the wild species and not in A. hypogaea, indicating that directional selection or the hitchhiking effect has played an important role in the domestication of the cultivated peanut. The 75 accessions were grouped into three clusters based on population structure and phylogenic analysis, consistent with their taxonomic sections, species and genome types. A. villosa and A. batizocoi were grouped with A. hypogaea, suggesting the close relationship between these two diploid wild species and the cultivated peanut. Considerable phenotypic variation in oil content was observed among different sections and species. Nine alleles were identified as associated with oil content based on association analysis, of these, three alleles were associated with higher oil content but were absent in the cultivated peanut. The results demonstrated that there is great potential to increase the oil content in A. hypogaea by using the wild Arachis germplasm.
Highlights
The genus Arachis originated in South America and contains at least 80 species that have been classified into nine taxonomic sections based on morphological variation, geographical distribution and cross-compatibility [1,2]
The Genetic Diversity of 75 Arachis Accessions The 75 Arachis accessions used in this study belong to 20 species from 5 sections
The evaluation of the genetic diversity in Arachis germplasm is crucial for the efficient exploitation of the valuable alleles present in wild species during cultivated peanut improvement, which has been demonstrated in several previous studies [23,24,25]
Summary
The genus Arachis originated in South America and contains at least 80 species that have been classified into nine taxonomic sections based on morphological variation, geographical distribution and cross-compatibility [1,2]. Some Arachis species are used as forage for animal production in Asia and Africa. The most economically important species in the genus is the cultivated peanut Arachis hypogaea. Peanuts are widely grown in more than 100 countries and are used to produce food and edible oil for human consumption. Because the amount of peanut oil used in developing countries is increasing, more than 60% of peanuts produced worldwide are crushed for edible oil Enhancing the oil content of peanut cultivars is becoming an increasingly important breeding objective in most developing countries
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
