Production Practices and Quality Assessment of Food Crops. Vol. 1

148 S. Pereira-Lorenzo and A. M. Ramos-Cabrer
Figure 24. Bark graft in spring.
May, leaves from the lower part of the shoots are removed and girdled with wire
with hormones applied. Afterwards, the part is covered with a mound of soil to
produce etiolation. When the leaves fall in the autumn, new rooted shoots are
severed. Main problems of this propagation system are the low number of propagules
obtained from the mother plant, labour intensity and unfit plants produced
because of the vigorous aereal part in relation to the limited root system (only the
5 to 10% of the total dry matter; Miranda-Fontaíña and Fernandez-Lopez, 1992).
Clonal variation is an important factor in the number of shoots by mother plant;
range from 11.1 to 23.3 and in the number of shoots with a well-developed rooting
system, and between 30.5% and 49.6% (Miranda-Fontaíña and Fernandez-Lopez,
1992).