Evaluating of Peanut Breeding Lines with Resistance to the Peanut Root-Knot Nematode 1

The peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] causes significant economic losses throughout the peanut (Arachis hypogaea L.) production areas of the southern USA. No resistant peanut cultivars are available; however, a breeding line (UF81206) has been observed to be less sensitive to M. arenaria than commercial cultivars. The objectives of this study were to evaluate the sensitivity to M. arenaria of UF81206 and related breeding lines and to determine if these responses are due to tolerance, or resistance. The yield of 10 peanut genotypes was evaluated for 2 yr in a field with high M. arenaria population densities and in a field with little or no M. arenaria. Two greenhouse tests were conducted to measure nematode reproduction. The breeding lines UF81206-Q4, UF81206, and UF93111 yielded similarly to Florunner when grown in fields with no nematodes and significantly higher than Florunner when grown in fields with high nematode population densities. These genotypes also supported less nematode reproduction in greenhouse trials, indicating that these genotypes have a moderate level of resistance. PI203396 is in the pedigree of these breeding lines and also exhibited a moderate level of resistance in a greenhouse trial.