Salinity tolerance of 12 turfgrasses in four groups, creeping bentgrass (Agrostis stolonifera L.), fescues (Festuca spp.), kentucky bluegrass (Poa pratesis L.), and alkaligrass [Puccinellia distans (Jacq.) Parl.], was evaluated using three germination methods. Seeds were germinated on 1% agar medium, on germination paper, or in a hydroponic system under salinity levels of 0, 5, 10, 15, or 20 g·L−1 NaCl. Germination rate and seedling growth of each grass were determined. Salinity reduced the final germination rate (FGR), daily germination rate (DGR), and seedling leaf area (LA) in all tests. On agar medium, no significant difference in salinity tolerance was observed among the four turf groups; however, ‘Turf Blue’ kentucky bluegrass with a corn starch-based coating (coated ‘Turf Blue’) showed a significant higher salinity tolerance than the uncoated one. Using germination paper, creeping bentgrass required the highest salinity level to cause 50% reduction in FGR followed by alkaligrass, fescues, and kentucky bluegrass. Kentucky bluegrass required the lowest salinity level (9.5 g·L−1) to reduce DGR by 50%. With the hydroponic system, alkaligrass required a salinity level of 26.3 g·L−1 to reduce FGR by 50%, the highest among the four groups. Alkaligrass showed again the highest salinity tolerance with an average of 12.7 g·L−1 needed to reduce LA by 50%. Among the grasses, coated ‘Turf Blue’ kentucky bluegrass, ‘Declaration’ creeping bentgrass, and ‘Fults’ alkaligrass showed the highest salinity tolerance when evaluated on agar medium, on germination paper, or in the hydroponic system, respectively. The present study determined the salinity tolerance of 12 turfgrasses at seed germination and early seedling growth stages and showed that the germination method was a factor affecting the evaluation result and it should be considered in a seed germination test of turfgrass for salinity tolerance.

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Salinity tolerance of five buffalograss [Buchloe dactyloides (Nutt.) Englem.] cultivars (Texoka, Cody, Bison, Sharp's Improved II, and Bowie) and three blue grama [Bouteloua gracilis (Willd. ex Kunth) Lag. ex Griffiths] ecotypes (‘Lovington’, ‘Hachita’, and ‘Bad River’) was determined during in vitro seed germination and vegetative growth in a hydroponic system. Seeds were germinated on 0.6% agar medium supplemented with NaCl at 0, 5, 10, 15, and 20 g·L−1. Salinity reduced the final germination rate (FGR) and daily germination rate (DGR). Similarly, shoot dry weight (SDW), longest root length (LRL), and percentage of green tissue (PGT) of mature grasses declined with increasing salinity levels (NaCl = 0, 2.5, 5, 7.5, and 10 g·L−1). However, root dry weight (RDW) was not significantly affected by salinity. Blue grama exhibited a lower reduction in FGR and DGR than buffalograss at salinity levels lower than 10 g·L−1. Germination of all buffalograss cultivars and ‘Hachita’ blue grama was inhibited at salinity levels of 15 and 20 g·L−1 NaCl. However, buffalograss was more salt-tolerant than blue grama at the vegetative growth stage. Variations of salinity tolerance were observed within buffalograss cultivars and blue grama ecotypes, especially during the seed germination stage. Overall, buffalograss appeared to be salt-sensitive during germination but moderately salt-tolerant at the mature stage. However, blue grama was more salt-tolerant at the germination stage than the mature stage. Noticeable differences in salinity tolerance were observed between different germplasms. Therefore, salt tolerance of buffalograss and blue grama may be improved through turfgrass breeding efforts.

Salinity and waterlogging are two major abiotic stressors commonly associated with irrigated soils. In this experiment, tall fescue cv. Stonewall, Kentucky bluegrass cv. Bewitched, blue grama ecotype Bad River, and buffalograss cv. Texoka were germinated under well‐drained (control), waterlogging (i.e., flooding), saline (5 g NaCl/liter), or a combination of waterlogging and saline conditions (saline‐waterlogging) in two greenhouses (Study I and II). Plants were evaluated on germination percentage, shoot and root fresh weight, and the longest root length. Waterlogging with tap water did not inhibit seed germination or seedling growth. Germination, shoot and root fresh weight, and the longest root length were significantly decreased under saline conditions, alone or combined with waterlogging. The highest reduction occurred under saline condition alone which ranged from 36% of the control in the longest root length in Study I to 1% of the control in root fresh weight in Study II. Soil salinity levels were similar between the control and waterlogging treatments, which was significantly lower than the salinity treatment and the combined effects. Tall fescue was the most tolerant to both salinity and waterlogging stresses. Kentucky bluegrass, blue grama, and buffalograss showed a similar level of tolerance to salinity, waterlogging, and the combined stress.

Glycinebetaine (GB) seed priming enhances stress tolerance in various plants during the germination and seedling growth stage; however, information regarding turfgrass is limited. In this study, GB at 5 to 50 mm was used to prime seeds of six turfgrass species to evaluate the potential of GB priming in enhancing tolerance to drought, salinity, and sub-optimal temperature during germination. Stress tolerance was determined as relative final germination percentage (FGP) and daily germination percentage (DGP), expressed as percentage of germination under stress conditions compared with the control treatment (i.e., unprimed seeds germinated under non-stress condition) for each species. Daily germination percentage was more sensitive to stress than FGP. Perennial ryegrass (Lolium perenne L.) showed high tolerance to drought, salinity, and chilling temperatures (5 and 10 °C below optimal germination temperature) followed by tall fescue (Festuca arundinacea Schreb.) and creeping bentgrass (Agrostis palustris L.), whereas kentucky bluegrass (Poa pratensis L.), bermudagrass [Cynodon dactylon var. dactylon (L.) Pers.], and zoysiagrass (Zoysia japonica Steud.) were stress-sensitive. Kentucky bluegrass and bermudagrass showed higher germination at 10 mm GB under temperature stress and drought and temperature stresses, respectively; however, other grasses showed limited responses to seed priming. Our results showed that the efficacy of GB priming is plant-, GB concentration-, and stressor-dependent.