Oil, sugar, and starch characteristics in peanut breeding lines selected for low and high oil content and their combining ability

Peanut seeds contain approximately 50% oil on a dry weight basis, making them a high fat food. Reduction of the oil content would make peanuts a more desirable food to fat conscious consumers. Removal of existing oil by processing is not feasible for in-shell peanuts, the dominant product of the North Carolina-Virginia area. To reduce oil content in in-shell peanuts, a genetic solution must be found. However, while reduced oil content is a desirable objective, changes in oil must not be accompanied by significant decreases in any of the desirable aspects of peanut flavor. Because the impact of selection for low or high oil on flavor is not known, it would be useful to know in what form dry matter is being stored in the seed, particularly if it is not being stored as oil. Screening of 584 accessions identified two lines (PI 269723 and PI 315608) with high and two (Robusto 2 and Robusto 3) with low oil contents, each pair differing in sugar content. The four parents were crossed in diallel fashion to investigate patterns of inheritance. General combining abilities (GCA) for oil content closely followed values of the parental lines. One low oil parent (Robusto 2) had a correspondingly elevated GCA for sugar content, but neither low oil parent had the effect of elevating starch in progeny. Reciprocal cross differences were found for starch and sugar contents, suggesting influences of cytoplasmic genes on those traits. These lines serve as resource material for researchers interested in the genetic and physiological aspects of the oil-sugar-starch relationship in peanuts.