Repeated foliar sprays of abscisic acid to strawberry plants influence plant growth and yield
Deyton, D. E., C. E. Sams, and J. C. Cummins.  2017.  HortScience, Waikoloa, Hawaii, September 19-22, 2017.

Abstract:
‘Sweet Ann’ day-neutral strawberry plug plants were planted on 2 October 2015 in 3.79 L pots containing 3:1 mixture of perlite and peat moss. The plants were grown in a greenhouse with fertigation of calcium nitrate and Chem-gro 8-12-32 supplying 80 mg/L of nitrogen after the third week of establishment. First flowering occurred on 19 January 2016. The plants were sprayed with 0, 25, 50, 100, 150, 200, or 250 mg/L of abscisic acid (ABA) on 7 and 26 January; 9 and 25 February; and 8 and 23 March. The media was shielded from ABA contact to reduce root uptake. Treatments were arranged in a randomized block design with eight replications and four plants per replication. Plants were harvested approximately twice a week from 15 February until 24 May. Fruit were graded into commercial (>10 g) and non-commercial (<10 g and deformed fruit) and weighed and counted at each harvest. Number and weight of commercial, non-commercial, and total fruit were less (P < 0.05, respectively) on plants sprayed with 50 to 250 mg/L of ABA than on control plants. Fruit were slightly smaller (P < 0.05) on plants treated with 100 to 250 mg/L of ABA. However, total soluble solid content of fruit sampled in February-March (P = 0.230) and in April-May (P = 0.117) were not affected by ABA treatments. The above media surface of the plants were partitioned into crowns, leaves, and fruit. The numbers of crowns/plant were not affected by ABA treatment (P = 0.349). The fresh weights of crowns, leaves, and fruit of plants sprayed with 100 to 250 mg/L of ABA were less than for control plants (P < 0.05). Plants sprayed with 25 to 250 mg/L ABA had lower crown and leaf dry weights than control plants. Dry weights of fruit were not taken. The crown plus leaf dry weights of plants treated with 150, 200, or 250 mg/L of ABA were 66, 59, and 57 percent, respectively, of dry weights of control plants.