This paper reports the fruit set potential and effects of 12% urea on fruit drop in peach and nectarine selections in meadow orchard (5,000 plants per hectare). The experimental plot was located at the Estação Experimental of Monte Alegre do Sul (22°41'S. and 46°43'W.) of the Instituto Agronômico (IAC), State of São Paulo, Brazil, which has a record of 40 hours per year with temperature bellow 7°C. The best fruit set was obtained by Talismã', IAC 6782-83, IAC N 2680-91, 'Aurora-2' and IAC 282-24, showing 60.9, 54.2, 44.6, 41.4 and 40.0% respectively. The urea 12%, sprayed at full bloom stage, significantly decreased fruit set to 12-17%. The average fruit number remaining per branch was, respectively: 1.1, 1.6, 1.8, 1.9, 2.0, 2.6 and 3.2 for IAC 280-28, IAC 6782-83, 'Aurora-2', IAC 282-24, IAC N 1880-76, IAC N 2680-91 and 'Talismã'. The selections which held up to two fruits per branch showed better products.
peach; Prunis persica (L.) Batsch; nectarine; Prunus persica (L.) Batsch; var. nucipersica; fruit set; fruit drop; chemical thinning; urea; meadow orchard