( 7 > 
in Government employ in order to ensure the con- 
tinuity of work which must spread over more than 
•a dozen years. In order to obtain a high yielding, 
healthy strain of Hevea it is necessary to isolate 
a single strain, possessing the required characters, 
which will breed true to type. Through cross 
fertilisation in several generations, the present 
plantation rubber tree is of very complex nature 
and to isolate such a strain requires a large amount 
of systematic work, especially since at least three 
characteristics are involved, namely yield, quality, 
and disease resistance. Work of this nature has 
been initiated in Java, though little is known as to 
its progress to date. 
Vegetative Methods of propagating vegeta tively 
Propagation, good yielding parent trees may be 
divided into two groups; those provid- 
ing for their own root system, and those in which 
•one tree is grafted on to another. It is probable 
that the root system is as important to latex pro- 
duction as are the parts above ground. Methods 
of developing root systems include marcotting and 
cuttings. The former has been carried out success- 
fully in Java but it is laborious and difficult, and 
requires horticultural experience. 
'Cuttings carry with them the characteristic root 
system of the parent tree as far as is known, and 
if the roots develop well this method of propagation 
is to be preferred to all others. Unfortunately, this 
method of propagating selected parents has not, so 
far, been sufficiently successful t<T warrant its adop- 
tion on estates, but experiments are still in operation. 
Methods whereby a high yielding, disease-resistant 
tree is grafted upon another root system are 
numerous. One of the simplest is budding, which 
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