Seasonal Changes in the Amounts of White Unsuberized Root on Pear Trees on Quince Rootstock

Abstract

SummaryThe amounts of unsuberized white root observed in glass panels, from two young deblossomed pear trees on Quince A rootstock, were measured at weekly intervals over three years under irrigated soil conditions. In the two years for which comparison was possible, the spring increase in unsuberized white root, due to new root production, occurred later on the pear trees than on neighbouring apple trees. Although root production on one pear tree was reduced in one year when that tree was stimulated into more vigorous shoot growth by pruning and in another year during a period of secondary shoot growth, the typical white root curve for this kind of tree showed only a single peak in the summer and not the pronounced double peak typical of young Worcester Pearmain apple trees investigated earlier. It is suggested that this was due to the smaller numbers of growing shoots per 100 buds burst on the pear trees. The cortex of the quince roots turned brown within a few weeks, as has been described for apple tre...