Exploring Genetic Diversity and Nutritional Potential in Cultivated and Wild Peanut Germplasm for Molecular and Biofortification Breeding.

Peanut seeds are nutritious, containing about 50% oil, 25% protein, 15% carbohydrates, 2% fiber, plus useful phytochemicals (such as flavonoids, tocopherol, folate, and resveratrol) and minerals, which play important roles in human health. Natural genetic diversity and nutritional potential exist in cultivated and wild peanut germplasm. Exploring genetic diversity and nutritional potential by large-scale screening of peanut germplasm accessions with DNA markers and chemical analysis can help to identify unique accessions. These accessions can be used as genetic resources for molecular and biofortification breeding. Over 7,550 cultivated and wild peanut germplasm accessions have been evaluated for oil content, fatty acid composition (eight major fatty acids), and 100-seed weight. Significant variability was identified in oil content (from 37.6 to 58.8% and from 41.7 to 61.3%), oleic acid content (from 31.0 to 81.0% and from 15.2 to 51.3%), and 100-seed weight (from 21.8 to160.2 g and from 4.2 to 46.0 g) for cultivated and wild peanut, respectively. Accessions with high oil content, high seed weight, and high oleate are being used in peanut breeding programs. Among five high oleate mutants identified, three belonged to the subspecies fastigiata and two belonged to the subspecies hypogaea. DNA markers were also developed for these two classes of mutants using real-time PCR and allele-specific PCR, respectively. The U.S. peanut mini-core is a good subset of samples to use for evaluation of the cultivated peanut collection. Protein content, minerals, resveratrol, and flavonoids have been evaluated in this mini-core. Significant variability was identified for these evaluated chemical traits.