Agriculture Reference
In-Depth Information
it is a late bearer, with fruit maturing from August through October, greatly
extending the season (Hamilton
et al.
,
1992). 'Exel' was also selected from a
population of 'Irwin' seedlings for its high quality, attractive fruit and regular-
bearing habits, with fruit weight ranging from 400 to 500 g and with 18%
total soluble solids. Another desirable feature of the fruit is the thin, fl at seed,
which results in more than 90% edible fl esh (Ito
et al.
,
1992).
Isozyme analysis has been used to verify or refute parentage of mango
cultivars (Degani
et al.
,
1990). Isozymic banding has shown that 'Haden'
appears to be a seedling of 'Mulgoba', and 'Zill' a seedling of 'Haden'.
'Mulgoba' has the
ab
phenotype and 'Keitt' the
cc
phenotype, while 'Haden'
shows an
aa
phenotype, 'Carabao'
bb
and 'Edward'
ac
.
Newer molecular-
biology techniques are being used to unscramble the parentage of mangoes
and to determine the extent of genetic diversity (Krishna and Singh, 2007).
Rootstocks
Most mango plants are grafted on to polyembryonic rootstocks in order
to obtain plants that have a uniform root system, since they come from
an asexual process and so are clones. There are several rootstocks in each
country. In Latin America, some of the 'criollo' types of the Indochina-
Philippine group are used; however, not all are good rootstock. In Mexico,
the cultivar 'Manila' ('Carabao'), which is exported and consumed locally,
is used. Israel has developed '13-1' for saline and alkaline conditions. South
Africa uses 'Sabre' for sandy soils and '4/9' for heavy soils. In the Canary
Islands 'Gomera-1' and in mainland Spain 'Gomera-3' are used (Galán Saúco,
2009). Australia uses the polyembryonic 'Kensington Pride', which is also a
commercial fruit cultivar. Very little has been reported about the infl uence of
rootstock on the cultivar growth.
The Indian cultivars 'Olour', 'Vellai Colamban' and 'Saber' are used as
rootstocks to reduce tree vigour. Researchers have sought rootstocks with
special attributes, such as dwarfi ng habit and tolerance to high pH and saline
conditions. Two Indian hybrid cultivars, 'Mallika' ('Neelum' × 'Dashehari')
and 'Amrapali' ('Dashehari' × 'Neelum'), have been reported to exhibit distinctly
dwarfi sh characteristics in terms of trunk circumference, tree height and canopy
diameter in Brazil (Pinto and Sharma, 1984). Tolerance to saline soils has been
identifi ed, and cultivar '13-1' is being used commercially as a rootstock in Israel,
where calcareous soil and saline irrigation water pose serious problems (Gazit
and Kadman, 1980).
