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

Chestnut, an Ancient Crop with Future 129
the term ‘Marrone’, indicating as Breviglieri defined (1955) nuts of big size, monoembryonic,
bright clear colour, easy peeling and good flavour. However, other
cultivars not denominated ‘Marrone’ also produce good nuts (Table 11).
5. ROOTSTOCKS
Traditionally, growers have used seedlings (in Europe of C. sativa) coming from
seeds germinated under the grafted trees to establish the new orchards. These
rootstocks present a very good compatibility and are very rustic. Recently, Soylu
and Serdar (2000) have initiated in Turkey a selection program of mother trees as
producers of seedlings for chestnut rootstocks with good emergence rate, growth
and drought tolerance. However, they are expected to be susceptible to ink
disease.
At the beginning of the 20th century, researchers from France, Spain, Italy and
Portugal introduced seeds of C. crenata from Japan and C. mollissima from China
into Europe. These species are resistant to the ink disease, but their nuts were not
appreciated by growers because of the poor peeling. Also they were not particularly
vigorous to produce timber. Later, they were tried as rootstocks, but
incompatibility appeared. Interspecific hybrids were made and some clones were
selected as rootstocks, combining resistance to ink disease, easy propagation, good
compatibility and rusticity. Nevertheless, most of the hybrid rootstocks did not
combine all these characteristics.
Compatibility in chestnut was studied in the past by Urquijo (1957) and later
by Jaynes (1979), who advised on the need for further studies on specific rootstock-scion
combinations. More recently, Breisch (1995) pointed out different
compatibility relationships between French rootstocks and cultivars (Table 12).
Pereira-Lorenzo and Fernandez-Lopez (1997a) found a strong incompatibility
between Marigoule and Spanish cultivars. That incompatibility was shown at the
beginning of the third growth of the cultivars grafted by budding. The scion died
while the rootstock was alive (Figure 9). Local incompatibility by weak union at
the graft point can be observed due to the lack of fibrous connections.
Only France and Spain commercialise their resistant hybrid rootstocks propagated
by stooling, cuttings or in vitro culture. Five French (Breisch, 1995) and four Spanish
hybrid clones (Pereira-Lorenzo and Fernandez-Lopez, 1997a and Pereira-Lorenzo
et al., 2000) are recommended. Between Spanish rootstocks, CHR-151 (HS) has
been broadly used and it propagates very well by in vitro culture (Miranda-Fontaíña
and Fernandez-Lopez, 1992).
Resistance to the ink disease is from low to very high resistance for French
rootstocks (Breisch, 1995), while the Spanish hybrids varied between very resistance
to medium level (Fernandez-Lopez et al., 2002).
Breisch (1995) indicated the high sensitivity of French rootstocks to early
spring frosts (Table 12). Spanish hybrid rootstocks in traditional orchards localised
between 400 and 600 m, which were evaluated during the last 14 years (Pereira-
Lorenzo et al., 2000), showed resistance to frost. They are very sensitive during