Fruit yield and survival of five commercial strawberry cultivars under field cultivation and salinity stress

Authors: Ferreira, Jorge; Liu, Xuan; Suarez, Donald

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2018
Publication Date: 9/5/2018
Citation: Ferreira, J.F., Liu, X., Suarez, D.L. 2019. Fruit yield and survival of five commercial strawberry cultivars under field cultivation and salinity stress. Scientia Horticulturae. 243:401-410. https://doi.org/10.1016/j.scienta.2018.07.016.
DOI: https://doi.org/10.1016/j.scienta.2018.07.016

Interpretive Summary: Strawberry is one of the most salt-sensitive horticultural crops. The crop is very important to the economies of both United States and California, the highest producer country and state, respectively. However, the decreasing quality of irrigation water is a growing concern among strawberry growers in semiarid producing areas of the world, including southern California. We evaluated five commercial cultivars under irrigation waters of increasing salinity, expressed by their electrical conductivities (ECiw) of 0.7, 1.0, 1.5, and 2.5 dS m-1 in a field plot experiment, under drip irrigation. Although increased ECiw increased Cl- in all tissues, Na+ only increased in roots and stems. Leaves of all cultivars maintained good levels of both macro and micronutrients with no evidence of competition between sodium and the essential minerals potassium, or calcium or between chloride and the essential mineral nitrogen. All cultivars had decreased fruit production, even when ECiw increased from 0.7 to 1.0 dS m-1, and with further yield decreases up to ECiw=2.5 dS m-1. Although Albion and San Andreas had the least fruit yield at control salinity, Albion was the cultivar with the least reduction in fruit yield, biomass, and survival at ECiw=2.5 dS m-1, and thus the most salt tolerant. In terms of absolute yield under saline conditions, Monterey was the highest fruit producer. All cultivars maintained their total soluble sugars (Brix%) across salinity levels but Albion, Monterey, and Benicia had the highest Brix% regardless of salinity. The results indicate that these newer commercial cultivars are more salt-tolerant that previously tested cultivars, and have enough variability in salt tolerance to enable selection based on that criterion for irrigation water salinity with ECiw >1.0 dS m-1. These commercial cultivars enable farmers to produce strawberries at irrigation water salinity up to 1.5 dS m-1, albeit with a commercial loss in fruit yield. Benicia, Monterey, and Albion had higher fruit yields at ECw= 2.5 dS m-1 as compared to the other varieties. This research is of interest to strawberry breeders, extension specialists, and growers.

Technical Abstract: Strawberry is one of the most salt-sensitive horticultural crops, and important to the economies of both United States and California, the highest producer country and state, respectively. Thus, the increasing salinity (electrical conductivity) of irrigation water (ECiw) in semiarid areas of the world is a growing concern to strawberry growers. We evaluated five commercial cultivars under the ECiw of 0.7 (control), 1.0, 1.5, and 2.5'dS'm-1, under field conditions for 240 days. Increased ECiw increased Cl- in all tissues, while Na+ only increased in roots and petioles. Thus, toxic effects of salinity in leaves were attributed to Cl-, not Na+. All cultivars maintained sufficient levels of both macro and micronutrients in shoots without competition between Na+ and K+, or Ca2+ or between Cl- and NO3-. All cultivars had decreased fruit production, even when ECiw increased to 1.0'dS'm-1. Although ‘Albion’ and ‘San Andreas’ had the least fruit yield at control salinity, ‘Albion’ was the cultivar with the least mean relative reduction in fruit yield, marketable fruit size, shoot'+'root biomass, and survival at ECiw'='2.5'dS m-1, and thus the most salt tolerant. Regarding absolute yield, ‘Monterey’ was the highest fruit producer under salinity. All cultivars maintained fruit total soluble sugars (Brix%) across salinity levels with ‘Albion’, ‘Monterey’, and ‘Benicia’ having the highest values (11–13% Brix) regardless of salinity. ‘Albion’ and ‘San Andreas’ were the best at maintaining commercial fruit size under salinity. ‘Albion’, ‘Benicia’, and ‘Monterey’ had higher fruit yields at ECiw'='2.5'dS m-1 than ‘Ventana’ and ‘San Andreas’ and can enable farmers to produce strawberries with irrigation water ECiw up to 1.5'dS'm-1, although with some fruit yield loss. Results indicate that these newer commercial cultivars are more salt-tolerant than cultivars previously tested, and with enough variability in salt tolerance to improve selection for irrigation water salinity with ECiw >1.0'dS'm-1.