A Whole Plant Microculture Selection System for Kentucky Bluegrass
- M. A. Pieper and
- M. A. L. Smith
Breeding advances in turfgrasses are constrained because environmental variation makes it difficult to identify and select useful traits in conventional field plots. A continuous whole plant microculture system for Kentucky bluegrass (Poa pratensis L.) was therefore developed as a practical selection and testing tool, consistent source of explants, and rapid means of propagation for new clonal selections. Stable, fully differentiated grass plant microcultures were readily produced on hormone-free medium and maintained indefinitely by nodal subculture with greater efficiency than those produced by seed or greenhouse node explants. Advantages of these whole plant microcultures over test plants grown in vivo (highly regulated environment, compact and portable vessels, root systems that can be observed over time without intruding the growth environment) were illustrated in two different experimental applications. Osmotic potential adjustments in response to environmental stress were effectively demonstrated under strictly regulated conditions using bluegrass leaves from microculture, and time course evaluations of root rot pathogen symptoms allowed quantitative assessment of disease progression in vitro. Microcultures were transplanted successfully into greenhouse conditions, allowing parallel in vitro and in vivo tests and multiplication of selection lines. The methodology is especially valuable because it results in continuous maintenance of stable, uniform, differentiated plants, and their direct use in research analysis. This experimental system has potential as a vehicle for directed research on turf and pasture grasses.
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