I - --ii

156
Morpho!ogical and Crop Density Factors
The results given in fable 6 suggest that, under favorable or intermediate
environmental conditions (Jindiress and Tel Haya, respectively), the erect form
of chickpea (ILC 72), when winter sown at 30 p!ants/m 2 , is less productive than
the spreading form (ILC 482) in both drymatter and seed yield. This is particularly
true in the latter case, where, though development of a tall stem structure
may reduce canopy size somewhat (Table 2), it has a significantly greater effect
in reducing the conversion efficiency of dry matter to seed yield. This isexpressed
by harvest index values for the erect cultivar close to 0.41 as compared with
values close to 0.55 for the winter-sown spreading cultivar. This reduced efficiency
of drymatter conversion to seed yield is exemplified in the yield results for the
densely planted treatment (60 plants/m 2 ). The results given in Table 7 show that
this treatment achieved comparable or greater drymatter production than ILC
482 but its seed yield was consistently lower. Also, harvest index was apparently
reduced by increased density in ILC 72 tlereby exaggerating the cu!tivar differential.
This suggests that increasing plant density in erect cultivars may not
necessarily be an efficient manner by which yield levels can be increased, but it is
clear that. higher density plantings would probably outyield erect cultivars planted
at current standard density (30 plants/m 2 ) when moisture conditions prove to
be favorable (Table 7).
Conclusmii
Winter planting of chickpea crops in the wetter regions of northern Syria is likely
to be extremely productive. Even at the drier sites., such as Brida, where chickpeas
are not currently grown, at current market prices, this crop would be
competitive with the traditionally grown barley. Nevertheless, our data do suggest
that this crop is sensitive to moisture stress and this could kad to greater
instability of yield and farmer income than is associated with barley. It is likely
that further research efforts can identify crop cultivars and management practices
which reduce the risk factors involved. The results of this study suggest that
breeders should select very early maturing cultivars for the drier regions and that
agronomists should pay further attention to the interaction between moisture
supply, canopy development and productivity.