Abstract:
The present report is a part of a General Program of study effects of applications of growth retardants on industrial orchards of pears and apples, developed during 1.971, 1.972 and 1.973 by the author, and supported by a grant from Juan March Foundation.
The whole work has been published by National Institute for Agronomical Research (Madrid).
On reference to pear orchads we have work with "Blanca de Aranjuez" cultivar mainly; and also with "Hardy" pear.
"Blanca de Aranjuez" pear cultivar, is a tipical Spanish variety growth all over the country, in more than 6.500 Has. of regular orchards and yielding more than 50.000 Tms. per-year; is the third variety in Spain, afther "Limonera" and "Coscia", for production; and the most important one in relation with the fresh market and cold storage.
Notwithstanding "Blanca de Aranjuez" has many important agronomical problems: is very sensible to frost damage and to "Venturia pyrina"; presents difficulties in pollination and fecundation of flowers, and is so much vigorous and with late beginning to bear.
The possible control of its vegetative growth and flower bud differentiation, spraying with growth retardants, was the first purpose of this work.
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