Propagation through cuttings is one of the most common methods of perpetuating vegetable species.
It is restricted to varieties that are fully acclimatized to local conditions. Growers select plants that dis-
play the properties chosen for multiplication, such as nutritious leaf, higher yield, quick growth, and re-
sistance to diseases, insect pests, and drought. Resistance to drought is an important property to be asso-
ciated with other desirable characteristics in tropical and semiarid regions. Drought occurs frequently in
semiarid tropical regions, hence crop loss due to scarcity of water also occurs frequently. In addition to
the development of more suitable farming technology, evaluation of drought-resistant varieties is desir-
able.
The arid ecosystem environment offers an adaptive challange to the survival of plants: the only
species that can survive possess adaptive mechanisms that enable them to adjust under strong climatic
fluctuations [3]. According to Sen [3], ecophysiological studies are thus important for judging the ability
of a particular species to adjust under prevailing climatic (Figure 1) and edaphic conditions.
Available soil moisture is used by the roots of annual and perennial plants from the end of the rainy
season until early summer, by which time such moisture has been depleted. Later, a partial or total status
quo is maintained in soil moisture, mainly in the open, with the result that water loss is eliminated by shed-
ding or reduction of leaves by plants [3]. Whatever rainwater is retained by the soil is used by the roots
of annual and perennial species from June–July to November–December [4]. Physiological studies are
helpful in determining the individual and collective influence of different factors on vegetative propaga-
tion.
A. Significance of Vegetative Propagation
Rooting in stem cuttings can be important means of vegetative propagation for afforestation purposes. In
arid zones, quick establishment of plants with ample root systems is a necessity.
In arid regions, water in the form of precipitation is available only in the rainy season, and the plants
must be established in suitable conditions of soil moisture. Therefore, rooted stem cuttings are more use-
ful than seed sowing because rooted cuttings are far better able to survive in the stressful environment of
the desert than delicate seedlings.
128 SEN AND RAJPUTFigure 1 Climatic parameters at Jodhpur during 1992 RH relative humidity; PER potential evapotran-
spiration.