Runner Production of Strawberry Plants in Soilless Suspended System: Nitrogen Rate, GA3 and Genotype Effects

Abstract

Two separate experiments were conducted at the greenhouse facilities of the Department of Horticulture, Faculty of Agriculture, Suez Canal University during the period of 2014-2016 with the objective of optimizing strawberry runner and ramet production on soilless, suspended growing system. The first experiment aimed to test the effect of nitrogen fertilizer rates (500 vs. 1000 ppm), GA 3 sprays and their combinations. Results indicated that fertigation with high N rate in combination with GA 3 (50 ppm) spraying on mother plants resulted in higher runner number (37.7%), ramet number (45%) and runner length (19%) than the control. Fertigation with high N alone significantly increased mother plants crown diameter, crown FW and DW, number of leaves and leaf area over all other treatments. Application of N at 1000 ppm + GA 3 spraying increased N, P, Mg, Ca, Fe and Zn in mother plant leaves. The second experiment was conducted to evaluate different strawberry genotypes ('Festival', 'Tudla', 'Sweet Charlie', 'Gaviota' and 'Camarosa') for their runnering behavior in suspended growing system and the results indicated that cv. "Festival" produced higher runner and ramet number per mother plant, followed by cv. 'Tudla' compared to the other cultivars, while ramets FW was higher in cv. 'Gaviota' and 'Sweet Charlie' than 'Festival', 'Tudla' and 'Camarosa'. Mother plants of cv. 'Festival' recorded the highest crown diameter, crown FW and DW, followed by 'Gaviota', while cv. 'Sweet Charlie' recorded higher root length and root FW. The highest photosynthetic pigment contents were recorded in cv. 'Tudla', followed by 'Festival'. Nutrient analysis of leaves indicated that the highest N, Fe, Mn, Zn cud Cu were in leaves of cv. 'Festival', while 'Camarosa' recorded the highest P, and 'Sweet Charlie' had the highest K and Ca. RAPD-PCR analysis of DNA of the used strawberry cultivars indicated their different genetic makeup, with about 20% polymorphism using three selected primers which may explain their differences in runner production.