03142naa a2200313 a 450000100080000000500110000800800410001902200470006002400360010710000140014324501160015726000090027350004060028252017020068865000190239065300210240965300220243065300270245265300370247970000170251670000330253370000290256670000210259570000230261670000130263970000220265270000250267477301290269910637122023-06-09       2023    bl uuuu     u00u1 u    #d  a0721-7595 (print); 1435-8107 (electronic).7 a10.1007/s00344-022-10827-72DOI1 aCARRA, B.  aReturn bloom and yield of 'Rocha' pear trees are improved by Ethephon and Paclobutrazol.h[electronic resource]  c2023  aArticle history: Received 13 May 2022; Accepted 21 September 2022; Published online 6 October 2022; Published Print June 2023. -- Correspondence author:  Carra, B.; Instituto Nacional de Investigación Agropecuaria, INIA Las Brujas, Rincon del Colorado, Uruguay; email:bcarra@inia.org.uy  -- Funding: Conselho Nacional de Desenvolvimento Científico e Tecnológico, 140499/2015-6, 443135/2014-2, CNPq.  aABSTRACT.- Flower induction and differentiation are complex phenomenon not fully understood in pear trees. Paclobutrazol (Pbz), Ethephon (Eth), and naphthaleneacetic acid (NAA) exogenous applications could be potential tools to increase return bloom and yield, and to manage the alternate bearing in some pear cultivars. The objective of this research was to evaluate the effect of Eth, Pbz, and NAA on return bloom and yield of 'Rocha' pear trees in different climatic conditions of Southern Brazil. The experiments were performed during 2015/2016-2017/2018 growing seasons, in Sao Joaquim, Santa Catarina State, and during 2015/2016-2016/2017 growing seasons in Antonio Prado, Rio Grande do Sul State. The pear 'Rocha' were grafted on quince rootstock 'BA29' (experiment 1 and 3) and Pyrus calleryana (experiment 2). Treatments consisted of Eth, Pbz, NAA, and Eth + NAA sprayed at different concentrations and timings. Shoot length, pruning weight, fruit set, number of thinned fruit and total fruit per tree, yield, average fruit weight, flesh firmness, and soluble solids content were assessed. Shoot length decreased, whereas return bloom and yield components increased when using Eth, Pbz, and Eth + NAA in all experiments. However, the positive effect is only in the rate of 10 mg L-1 NAA in experiment 1. Fruit size was reduced in Eth concentrations above 300 mg L-1, as a direct effect of crop load. Our results show that Eth and Pbz increase return bloom and yield of 'Rocha' pear trees being a potential tool to improve flowering in warm winter Regions as Southern Brazil. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.  aPYRUS COMMUNIS  aFlower induction  aGrowth regulators  aNaphthaleneacetic acid  aSISTEMA VEGETAL INTENSIVO - INIA1 aHERTER, F.G.1 aMORETTI FERREIRA PINTO, F.A.1 aFONTANELLA BRIGHENTI, A.1 aPEREIRA PASA, C.1 aMELLO-FARIAS, P.C.1 aDINI, M.1 aSOZO DE ABREU, E.1 aDA SILVEIRA PASA, M.  tJournal of Plant Growth Regulation, 2023, Volume 42, Issue 6, pp. 3650-3661. doi: https://doi.org/10.1007/s00344-022-10827-7