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agalnsr varlous biotic and ahiotic constraints met with low success rates where
biotechnology may prove to be an effective altert~ative.
Evolution is a process of natural creation of var~ations in the genetic ~~iake-up of
organisms so that ~t firs into the variable conditions of the changing environnlent. This
process takes ~iiillio~is of years :ind 11 goes 011. As the requ~rcmct~ts doubled and tripled.
there is a ~necess~ty to induce val.iatiolls dellberatcly to lileet the 11ecd. This fart enierylnp
licld oi' pl;i~ir sclc~~cc ~;IIIIS 1t5 s~pi~ilic;~ncc ;illd tidv;~~lt:igc o\cr tllc Ilnllt:~tio~~r oi' !tic
genetlc recomb~nat~on by meatis of con\cntional breeditig. Thougll this tccliriiquc is bung
applied to many urganisnis, ~ncluding ni~crobes atid animals, the scope of [his thcs~s 1s
restricted to deal with plants only. Moreover, nlosl of tlie publislicd and on goilig \wrh IS
on platits whcn compared to the animals. Microbe transfonnatio~l is rather a procedure Tor
basic research and only a part of preparative tcchnique for the higher organibm
tratlsforniation.
/Genetic transformatio~i, 111 principle is ~ntegrntion of alien genes into the foreign
organisn~. Stable ~ntcgratioll arid lriheritalicc of ubcl'ul gcocs ib the main object~ve of gene
transfer enperlmentsy"&e
concept of genetic transt'ornlat~oli started with Avery et al.
(1944). In angiosperms, gene transfer, however, IS a regular process where paternal
chromosomes iioin the explod~iig sperm arc tr:insfcrred to the egg cell of tlie fen~,~le
gametopllyte (Frankel and Galun, 1977). So, the problem 1s to transfer tlie gencs
deliberately. Advent of plant tissue culture espec~ally the protoplast sola at ion (Cocking,
1960) and cybrid formation gave an encouragi~lg impetus to the concept of gene transfer.
Protoplast isolat~on resulted in cell-wall-stripped cells and rcgeneratioo from the wholl: