Salinity Tolerance of 33 Greens‐TypePoa annuaExperimental Lines

Abstract

Current literature suggests Poa annua L. (annual bluegrass) is intolerant to salinity stress. Response of greens‐type Poa annua to chronic salinity stress (12 wk at 8.0 dS m−1) was evaluated over two greenhouse experiments. Vegetative samples of 33 greens‐type P. annua experimental lines were maintained at a 6.4‐mm mowing height and irrigated daily with modified Hoagland's solutions possessing salinity levels of 0.7 dS m−1 (nonsaline control) or 8.0 dS m−1 (NaCl treatment, approaching 0.25 strength sea water, approx. 13.5 dS m−1). Clipping yield dry weight (CYD) and leaf water content (LWC) were measured weekly. Digital images were collected at the end of weeks 1, 4, 8, and 12 to determine percentage cover (PC) and dark green color index (DGCI). Across all lines, all sample dates, and both experiments, salinity stress significantly reduced PC (30.8%), DGCI (9.3%), CYD (33.9%), and LWC (3.3%) compared with nonsaline controls (α = 0.05), suggesting chronic salinity stress is detrimental to greens‐type P. annua quality. However, significant differences in relative PC and relative CYD were observed among lines, indicating that substantial variation in salinity tolerance exists in greens‐type P. annua. Numerous greens‐types P. annua experimental lines, such as PSU 99‐9‐21, PSU 01‐1‐46, and PSU 05‐1‐14, possess moderate‐to‐good salinity tolerance and are potentially suitable for use on golf courses with moderate salt problems.

Salinity Effects on Seed Germination and Vegetative Growth of Greens‐Type Poa annua Relative to Other Cool‐Season Turfgrass Species

“…Lines PSU 99‐11‐6 and PSU 99‐9‐21 exhibited nearly equal salinity tolerance to that of perennial ryegrass Charger II and creeping bentgrass Mariner during seed germination. During vegetative growth, the salt tolerance ranking of the nine P. annua lines was found to be consistent with our previous 12‐wk chronic salt stress study (Dai et al, 2008). PSU 99‐2‐5 and PSU 99‐9‐21, though not as salt tolerant as Charger II, were nearly as salt tolerant as Mariner; and most greens‐type P. annua experimental lines were more tolerant than Kentucky bluegrass Moonlight during vegetative growth.…”

“…Some experimental lines displayed nearly equal salinity tolerance to that of perennial ryegrass Charger II and creeping bentgrass Mariner. Based on the results of the present studies in combination with our previous 12‐wk salt stress study (Dai et al, 2008), we conclude that the greens‐type P. annua experimental lines that we examined possess moderate to good salinity tolerance and particular experimental lines have potential to be used on golf courses with moderate salt problems affecting turf establishment and maintenance.…”

“…Research indicates that greens‐type P. annua possesses a wide range of variation in salinity tolerance. Among the nine experimental lines used in the present studies, a previous long‐term vegetative growth study indicated that PSU 99‐9‐21, PSU 01‐1‐46, and PSU 99‐2‐5 were the most salt‐tolerant, PSU 98‐3‐30 and PSU 96‐1‐9 the least, according to data on relative percent cover (Dai et al, 2008). In the present studies, the experimental lines of greens‐type P. annua were intermediate in the range of predicted salinity levels causing 25 and 50% reduction in FGP and GR, relative to the other turfgrass species examined.…”

“…Nine greens‐type P. annua experimental lines (PSU 96‐1‐9, PSU 98‐3‐30, PSU 98‐4‐21, PSU 99‐2‐5, PSU 99‐3‐19, PSU 99‐9‐21, PSU 99‐11‐6, PSU 01‐1‐46, and PSU 05‐1‐14) were chosen to represent the high to low range of salinity tolerance observed in a previous long‐term salinity stress study (Dai et al, 2008). Inclusion of other cool‐season turfgrass cultivars was based on published salt studies: three creeping bentgrass cultivars (Mariner, Seaside II, and ‘Penncross’) (Marcum, 2001), two Kentucky bluegrass cultivars (Moonlight and Northstar) (Qian et al, 2004; Rose‐Fricker and Wipff, 2001), and one perennial ryegrass cultivar (Charger II) (Rose‐Fricker and Wipff, 2001) (Table 1).…”

“…Literature suggests that among cool‐season turfgrass species, P. annua is very sensitive to salinity stress during vegetative growth, while perennial ryegrass is tolerant, creeping bentgrass moderately tolerant, and Kentucky bluegrass ( P. pratensis L.) moderately sensitive (Carrow and Duncan, 1998; Turgeon, 2008). However, recent greenhouse studies indicate that substantial variation in salinity tolerance exists among greens‐type P. annua experimental lines and that some lines were nearly unaffected by chronic salinity stress (12 wk at 8 dS m −1 ) (Dai et al, 2008). However, the salinity tolerance of greens‐type P. annua has not been compared to that of other cool‐season turfgrass species.…”