EVALUATION OF PEANUT BREEDING LINES WITH RESISTANCE TO THE PEANUT ROOT-KNOT NEMATODE

The peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood ra ce 1] causes significant economic losses throughout the peanut (Arachi s hypogaea L.) production areas of the southern USA. No resistant pean ut cultivars are available; however, a breeding-line (UF81206) has bee n observed to be less sensitive to M. arenaria than commercial cultiva rs. The objectives of this study were to evaluate the sensitivity to M . arenaria of UF81206 and related breeding lines and to determine if t hese-responses are due to tolerance, or resistance. The yield of 10 pe anut genotypes was evaluated for 2 yr in a field with high M. arenaria population densities and in a held 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 hig her than Florunner when grown in fields with high nematode population densities. These genotypes also supported less nematode reproduction i n greenhouse trials, indicating that these genotypes have a moderate l evel of resistance. PI203396 is in the pedigree of these breeding line s and also exhibited a moderate level of resistance in a greenhouse tr ial.