Effect of Prohexadione Calcium on Vegetative and Reproductive Development in Sweet Cherry Trees

Abstract

Cherry trees display vigorous upright growth, which tends to reduce precocity, flower bud formation and fruit quality. Three trials were performed in the 2010-2011 season on mature 'Lapins' and 'Sweetheart' sweet cherry trees in the Angol area (37°48'50"S, 72°37'36"W). The effects of prohexadione calcium (P-Ca) on shoot growth, leaf area, yield, fruit quality and flower differentiation were assessed. Two rates were evaluated (150 mg L-1 and 250 mg L-1), which were sprayed when shoots were 15 cm long and 15 days later or after harvest. The P-Ca treatment reduced the elongation of terminal shoot in both cultivars, which was due to reducing both length and number of internodes, resulting in a reduction in total leaf area. This led to better light penetration and distribution in tree canopies. Applications of P-Ca to shoots 13 to 15 cm in length controlled shoot growth adequately, while the effect was excessive when the spray was repeated after 15 days. No additional effect was detected when the second application was applied after harvest. P-Ca treatments increased the number and size of reproductive buds and the number of floral primordia per bud. The development of floral structures in the buds was more advanced compared to the control. Regarding fruit quality, soluble solids concentration and fruit size there were no significant effect from P-Ca application, while the fruit firmness increased. One single application of P-Ca at 250 mg L-1 in spring appears to be the most effective treatment to control vegetative growth, to increase the number of flower buds and to improve fruit firmness.

Prohexadione-Ca and Ethephon Suppress Shoot Growth of Sweet Cherries (P. Avium)

“…This study indicates that under Southern Ontario climatic conditions, P-Ca can markedly decrease the vegetative shoot growth of sweet cherry trees on rootstocks that promote medium-high to high vigor. This is consistent with the results of past experiments conducted in Summerland, BC (Guak et al 2005), Poland (Jacyna and Lipa 2010;Jacyna et al 2012), Chile (Cares et al 2014), and the Pacific Northwest region of the USA (Elfving et al 2003(Elfving et al , 2004(Elfving et al , 2005.…”

“…As P-Ca degrades within a matter of weeks following its application (Evans et al 1999), there was likely very little or none of the pre-bloom P-Ca remaining in the shoots that received this treatment by the time they began to grow actively. Similar observations have also been made with P-Ca applications made either after harvest (Cares et al 2014) or in the fall (Manríquez et al 2005). Due to the low persistence of P-Ca, these observations support limiting the application of P-Ca to the period in which shoots are in active growth.…”

“…In accordance with this, previous studies reporting on vegetative growth control in sweet cherry have demonstrated that repeat applications of P-Ca at 246 mg L −1 spaced 2 wk apart can provide season-long inhibition of shoot growth (Guak et al 2005;Cares et al 2014). Contrary to observations made in the current study, Cares et al (2014) demonstrated that a single application of P-Ca at a rate of 246 mg L −1 was sufficient to provide season-long shoot growth reduction similar to that observed with the two applications of P-Ca. However, Guak et al (2005) observed that repeat applications of 123 mg L −1 P-Ca were insufficient in reducing shoot growth when compared with the control.…”

“…As a result, considerable research has been conducted with fruit trees, including sweet cherries, to explore the feasibility of using plant growth regulators (PGRs) to control shoot growth and affect flower initiation and fruit set. The gibberellin (GA) synthesis inhibitors daminozide and paclobutrazol have demonstrated effective control of vigorous sweet cherry shoot growth (Facteau and Rowe 1979;Facteau and Chestnut 1991); however, they are not commercially available for use on fruit trees in Canada and several other countries due to concerns over environmental persistence and residues in fruit (Rademacher 2004;Cares et al 2014).…”

Influence of Prohexadione-Calcium on Vegetative Growth and Reproduction of ‘0900 Ziraat’ Sweet Cherry

“…Present findings revealed that ProCa was effective in controlling vegetative growth of cherry trees. Complying with the current findings, a decrease was reported in vegetative growth with ProCa treatments in apples [Greene 1999;Unrath 1999], pears [Basak and Rademacher 2000;Costa et al 2001Costa et al , 2004Elfving et al 2002Elfving et al , 2003Rademacher et al 2004;Smit et al 2005;Asin et al 2007] and cherries [Manríquez et al 2001;Elfving et al 2003;Guak et al 2005;Jayna et al 2012;Cares et al 2014]. Such a decreasing effect of ProCa on vegetative growth may be attributed to inhibition of gibberellin synthesis promoting cell elongation.…”