Grasshopper [Melanoplus spp. and Cannula Pellucida (Scudder)] feeding is an important factor that can prevent establishment and reduce yields of alfalfa [Medicago sativa subsp. X varia (Martyn) Arcang.] interseeded into semiarid rangelands of the northern Great Plains. Objectives of this study were to determine narrow-sense heritability estimates of grasshopper preference for an alfalfa population and to develop low-preference alfalfa germplasm adapted to rangeland use. The base population was derived from 5 cultivars and an experimental strain, all of M. sativa L. subsp. sativa X M. sativa subsp. falcata (L.) Arcang. parentage, that had been developed for rangeland use in the northern Great Plains. Except for cycle 4 which was conducted in a greenhouse, each cycle of recurrent phenotypic selection involved transferring replicated half-sib families of 6- to 8-week-old plants in flats to a field site with a heavy infestation of grasshoppers. Half-sib families were scored for defoliation when the entire population was at least 50% defoliated. Narrow-sense heritability estimates of defoliation under greenhouse conditions for 31 half-sib families and their respective parents ranged from 45 to 58%, depending on how defoliation from the multi-specks grasshopper populations was measured. Alfalfa populations produced from cycles 1, 3, and 5 of recurrent phenotypic selection were evaluated simultaneously under greenhouse conditions with a common grasshopper population and rated for defoliation on a scale from 1-5 where 1 = 0-20% and 5 = 81-100% defoliation. Mean defoliation decreased significantly (P<0.05) from 3.83 to 3.25 from cycle 1 to cycle 3, but the small decrease from 3.25 to 3.15 from cycle 3 to cycle 5 was not significant. The lack of progress from cycle 3 to cycle 5 was attributed to a major change in species composition of the grasshopper populations used in the selection process. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.