Manipulating flowering time of Protea ‘Pink Ice’ in Chile to prevent losses by bud freeze injury

F. Schiappacasse, P. Rebolledo, L. Valdivia, A.I. Gerber
In Chile, stems of Protea ‘Pink Ice’ are harvested year round. The growing areas fulfill most climatic requirements, however some frost events occur from May to August, with the lowest temperatures being around -1.5°C in Huapi, Maule Region. Those frosts produce a permanent damage to the flower buds. The flowering time of some Protea cultivars can be manipulated by pruning to improve yield and quality. Untested on Protea ‘Pink Ice’ in Chile, this technique was thought to be a promising solution to prevent presence of small buds at the time of frost risk, thus reducing losses. It was proposed that pruning in November would produce a harvest time starting 13 months later, and concentrated between February and May, that would meet a high flower demand from the local market in the protea growing areas. In this study, treatments were: Control (only harvest cuts, the grower’s normal procedure); Pruning in November 2017 (heading cuts); Pruning in December 2017 (heading cuts). The harvest season from pruned plants started at the beginning of March 2019, with peak in May. No statistical differences in flower yield were found among treatments for any harvest month. No buds were present on pruned plants during the frosts that occurred in the beginning of the 2018 frost season. However, bud development continued longer than expected, and during the 2019 frost risk period, 6-7 frozen buds plant‑1 were recorded. There were no clear differences between pruning in November or December, except for stem length, with plants pruned in December having shorter stems. Consequently, growers have little interest in adopting these pruning procedures, since they were left without flower harvest for 13-14 months and the subsequent yield and quality was not different from the control treatment. This study contributes to a better understanding of the flowering response of Protea ‘Pink Ice’ in the coastal area of Chile.
Schiappacasse, F., Rebolledo, P., Valdivia, L. and Gerber, A.I. (2022). Manipulating flowering time of Protea ‘Pink Ice’ in Chile to prevent losses by bud freeze injury. Acta Hortic. 1347, 77-84
DOI: 10.17660/ActaHortic.2022.1347.12
pruning, heading, flower bud, Chilean Protea production

Acta Horticulturae