Genetic Diversity among Peanut Cultivars

An assessment of the genetic diversity among peanut ( Arachis hypogaea L.) cultivars released in the USA would be useful to scientists working with this crop. This study was conducted to determine contributions from ancestral lines and coefficients of parentage ( r ) for peanut cultivars released in the USA. Pedigrees were constructed and examined to determine relative contributions of ancestral lines. In addition, r values were calculated for 820 pairwise combinations of 41 cultivars and mean genetic contributions of the ancestral lines were determined. Among runner market‐type peanuts, ‘Dixie Giant’ was a germplasm source in all pedigrees, ‘Small White Spanish‐l’ occurred in over 90% of the pedigrees, and the two lines contributed nearly 50% of the germplasm of runner cultivars. The r values among seven of the eight runner eultivars developed since the release of ‘Florunner’ in 1969 averaged 0.32. Inclusion of the eighth cultivar, Tifrun, which is only distantly related to the other seven, lowered the r value to 0.20. The Virginia market‐type cultivars had a more diverse genetic background, with only Dixie Giant and ‘Jenkins Jumbo’ contributing more than 10% of the germplasm. The r values for the Virginia cultivars released since 1969 averaged 0.21. The average r value for crosses between runner and Virginia market types was 0.16, while Spanish cultivars, with the exception of Tifspan, were unrelated to either runner or Virginia cultivars. The coefficients of parentage can be used by researchers conducting breeding, genetic, or physiological studies where knowledge of the genetic diversity of peanut cultivar backgrounds is important.