Isolation Requirements for Foundation Alfalfa Seed Fields¹

Abstract

Two alfalfa (Medicago sativa L.) cultivars in commercial production were used to study isolation distance for foundation seed production using insect resistance traits as genetic markers. Twenty‐one seed samples were obtained for comparison with foundation and certified seed lots. Spotted alfalfa aphid [Therioaphis maculata (Buckton)] resistance values indicated adequate isolation at 0.4 km (1,320 feet) and no shift in resistance from breeder seed to the foundation seed generation. Resistance to pea aphid [Acyrthosiphon pisum (Harris)] could not be used to measure cross‐fertilization between cultivars because the range of resistance overlapped between cultivars.

Genetic Markers and Plant Genetic Resource Management

“…But a dominant allele, conferring scab resistance, served to measure pollen flow in a monoecious, inbred line of Cucumis sativus L. (Wehner and Jenkins 1985); and resistance to spotted alfalfa aphid [(Therioaphis maculata (Buckton)] documented minimum isolation distances and border effects in two commercial cultivars of Medicago sativa L. (Brown et al 1980(Brown et al , 1981.…”

Genetic Markers and Plant Genetic Resource Management

“…Monitoring germplasm's trueness-to-type with markers affecting insect and disease resistance (and with some morphological traits) may be limited by difficulties in accurately and reproducibly measuring gene expression. But a dominant allele, conferring scab resistance, served to measure pollen flow in a monoecious, inbred line of Cucumis sativus L. (Wehner and Jenkins 1985); and resistance to spotted alfalfa aphid [(Therioaphis maculata (Buckton)] documented minimum isolation distances and border effects in two commercial cultivars of Medicago sativa L. (Brown et al 1980(Brown et al , 1981. c. Isozymes, Seed Proteins, and DNA Markers.…”