M.L. Parker, M.B. Clark, C. Campbell
Abscisic acid (ABA) is one of the primary plant hormones reportedly involved in many plant responses to stress. Studies were undertaken to determine the effectiveness of exogenous ABA applications on bloom delay, fruit thinning, yield and fruit quality parameters at harvest in peach (Prunus persica L. Batsch). Foliar applications during the growing season (270 or 300 mg L-1) did not significantly affect shoot extension, fruit set or total yield and there were no consistent effects on flesh firmness, soluble solids content or red color development. Dormant applications to the top portion of the tree (300-1000 mg L-1) and dormant soil drench applications (150-500 mg L-1) were also evaluated. Three dormant applications of 300 mg L-1 ABA to the top portion of the plant may have accelerated bloom with no impact on fruit set in one year. Dormant soil applications did not appreciably affect bloom time consistently or fruit quality at harvest. A greenhouse study was also conducted with one year old grafted peach trees to see if a single ABA drench could impact young tree establishment under a drought condition. Dormant trees were potted, watered weekly and 59 days after planting, the pots were allowed to dry for approximately 10 days and then drenched with a 223 mg L-1 solution of ABA. After the ABA treatment one-half of the trees were watered 15 days later, and the other half 25 days after treatment when the untreated control trees were wilting. The trees were grown for the remainder of the season under optimal growing conditions. After leaf abscission the trees were destructively harvested and the trees treated with ABA had a significantly larger trunk diameter, 2-yr old fresh weight and overall tree fresh weight. The dry weight for the trees treated with ABA was significantly greater for the 1 and 2 year old wood, root system, and overall tree weight.
Parker, M.L., Clark, M.B. and Campbell, C. (2012). ABSCISIC ACID APPLICATIONS IN PEACH. Acta Hortic. 962, 403-409
DOI: 10.17660/ActaHortic.2012.962.55
Prunus persica, ABA, soil drench, tree growth, root growth

Acta Horticulturae