Breeding of Fruit and Plantation Crops 2 + 1

Acclimatization

• When a plant material is introduced into a new area, it has to adapt itself to the new environment. Thus, the process of adaptation of an individual to a changed climate, or the adjustment of a species or a population to a changed environment over a number of generations is called “acclimatization” or acclimation.
• A naturally cross-pollinated crop will adapt itself to the new environment more quickly than a self-pollinated crop. In gene recombinations, some of the genes be well adapted to the new environment, will be present very often in the cross pollinated crops due to frequent cross pollination.
• Similarly, the chances of a genetically variable population of a self-pollinated crop to become adapted to its new environment are greater than those of a pure-line.
• Newly introduced materials of unselected bulk may be promising in the initial phases of introduction but should prove very well in later years. This is because nature selects from the heterogeneous population superior genotypes that are better suited to the new environment from among the heterogenous population and multiplies them in the course of a few years.
• A pure-line, on the other hand, has practically no genetic variability and hence it does not offer much scope for making selection adaptable to the newer place in which it has been introduced. A pure-line thus very rarely succeeds as an introduction.
• Some of the most important commercial crops cultivated extensively in India today are introductions from other countries.
• Para rubber (Hevea sp), was first introduced from Brazil in 1873. One or two attempts of introduction of this crop did not prove to be successful, but now, India particularly Kerala has extensive plantations of rubber.
• Tapioca (Manihot esculenta) has been introduced into India by the Portuguese and the Dutch. It is now grown extensively in Kerala where, it is a staple food.
• Cinchona was first introduced into the Nilgiris from Peru in 1860. Later it was introduced into Darjeeling.
• Coffee (Coffea arabica) was first introduced into India in 1700 by a Muslim who returned from a pilgrimage to Mecca. Today, coffee is grown extensively in South India and is an important commercial crop both for internal consumption and for export.