Germination and Initial Growth of Kentucky Bluegrass in Soluble Salts
1983
Horst, G. L. | Taylor, R. M.
Kentucky bluegrass (Poa pratensis L.) has recently been considered for use as turf in high altitude regions of the arid Southwest where saline soils and saline irrigation water are a common problem. A laboratory experiment was conducted using saline hydroponic solutions with seeds of the bluegrass cultivars germinating and growing on floating mats. Solutions made from tap water consisted of 7500, 12 500, and 15 000 ppm NaCl and CaCl₂ by weight, on an equal basis. Total germination, days to initial germination, leaf blade length, and blade fresh weight were measured. The objectives of this study were to determine the relative interspecific salt tolerances during germination and seedling growth of 44 bluegrass cultivars. Cultivars had highly significant germination and germination rate responses to salt stress. Seedling growth responses as measured by blade length and blade fresh weight were also significant. We found that a hydroponic growth medium containing 7500 ppm NaCl and CaCl₂ salt would be suitable for identifying cultivars that have potential commercial value for saline growing conditions. At this salinity level, cultivars which average less than a 50% reduction in growth parameters relative to top yielding cultivars should be considered. A hydroponic medium with a salt concentration of 12 500 ppm would provide a suitable stress level for screening bluegrass genotypes for improved salt tolerance. Broad-sense heritability estimates indicate that blade length, germination percentage, and germination rate would be valuable selection criteria for use in screening Kentucky bluegrass cultivars for salt tolerance. Apomictic reproduction may limit genetic improvement from recurrent selection.
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