A Multi-site Pear-interstem Trial in the Netherlands and Belgium

Abstract

An interstem trial was planted in the spring of 1989 with two pear cultivars Conference and Doyenné du Comice on the tender Quince MC rootstock with six interstem cultivars, viz. Beurré d’Anjou, Beurré Hardy (standard), Doyenné du Comice, Nouveau Poiteau, Old Home and Flemish Beauty to determine the influence of the interstems on winter hardiness and growth control. Two-year-old trees budded directly on Quince MC served as controls. The trees were planted at two sites in The Netherlands and one in Belgium in single rows at distances ranging from 3.00m x 1.30m to 3.50m x 1.50m and trained as slender spindles. The trial was evaluated until 1998.

No damaging freezes occurred during the experimental period, therefore no conclusions could be drawn with regard to the winter hardiness of the interstem cultivars involved. Vigor control was obtained with Beurré d’Anjou and Flemish Beauty, probably as a result of incompatibility of these two interstem cultivars with the Quince MC rootstock. The interstems compatible with the Quince MC rootstock did not provide vigor control, or promoted it, as was the case with Old Home. The Old Home interstem reduced cropping. Nouveau Poiteau had a small negative effect on the fruit size of Conference. Beurré Hardy and Doyenné du Comice are useful interstems for Conference, but do not reduce vigour. For Doyenné du Comice, with the exception of the poorly compatible interstems, none of the other interstems studied reduced vigor.