Ch.8 — The Application of Genetics to Plants • 151 
iH’gun: in the' long-run it could ha\ e serious con- 
se(|uences tor the (|uality of uni\ ersity research. 
Despite these consti'aints, [)i'ogi'ess in o\er- 
coining the difficulties is continuing. .\t the 
prestigious 1980 (lordon Conference, w here sci- 
entists meet tt) e.xchange ideas and recent find- 
ings, plant moleculai' hiolog\' was added to the 
list of meetings for the first time. In addition, 
four other recent meetings ha\e concentrated 
on plant molecular hiolog\ . '' Up to .10 [)ercent 
of the par'ticipants at these meetings came from 
nonplant-oriented disciplines .searching for fu- 
ture re.search topics. I his influ.x of in\ estigators 
from other fields can he expected to enrich the 
\ariet\’ of appi'oaches u.sed to soKe the prob- 
lems of the plant hrt'eder. 
'^Genome Ort^nnization and Espression in Plants. .\ \ I'O sym- 
posium held in Kdinhurf’h. Srollund. July 1979: Gcnrtic Enf^ineering 
of Symbiotic \itmgen Fixation and Conservation of Fi.xed .\itrof^en. 
June 29-July 2. 19S0. raluH' City, ('alit': ' .Molerular Biologists l.<K)k 
at (ireen Plants. ' Siyth Annual Symposium. Sept. 29-Oel. 2. t9H(). 
Heidelberg. W est liermany: anil Fourth International Svmposium 
on .S'itro^en Fixation. Dec. l-.i. 19«0. Canberra, \ustralia. 
Impacts on generating nei 
Progress in the manipulation of gene expres- 
sion in eukaryotic (nucleus-containing) cells, 
which include the cells of higher plants, has 
been enormous. Most of the new methodologies 
have been derhed from fruit flies and mam- 
malian tissue culture lines: but many should be 
directly applicable to studies with plant genes. 
There has been great progress in isolating spe- 
cific RXA from plants, in cloning plant DNA, and 
in understanding more about the organization 
of plant genomes. Techniques are available for 
manipulating organs, tissues, cells, or pro- 
toplasts in culture; for selecting markers; for 
regenerating plants; and for testing the genetic 
basis of novel traits. So far however, these 
techniques are routine only in a few species. 
Perfecting procedures for regenerating single 
cells into whole plants is a prerequisite for the 
success of many of the novel genetic technol- 
ogies. In addition, work is progressing on 
\ iruses, the Ti plasmid of Agrobacterium, and 
engineered cloning vehicles for introducing 
DNA into plants in a directed fashion. There 
Finally, as a general rule, tradeoffs arise in 
the use of the new technologies that may inter- 
fere with their ajjplication. It is impossible to get 
something for nothing from nature— e.g., in ni- 
trogen fixation the symbiotic relationship bet- 
ween plant and micro-organism requires ener- 
gy' from tbe plant: screening for plants that can 
produce and transfer the end products of pho- 
tosynthesis to the nodules in the root more effi- 
ciently may reduce inorganic nitrogen require- 
ments hut may also reduce the overall yield. 
This was the case for the high lysine varieties of 
corn. (See Tech. Note 10, p. 163.) Farmers in the 
Lhiited States tended to avoid them because im- 
proving the protein quality reduced the yield, 
an unacceptable tradeoff at the market price. 
Thus, unless the genetic innovation fits the re- 
quii'ements of the total agricultural industry, 
potentials for crop improvement may not be 
realized. 
varieties 
have been few demonstrations in which the in- 
heritance of a new trait was maintained over 
several sexual generations in the whole plant. 
Because new varieties have to be tested 
under different environmental conditions once 
the problems of plant regeneration are over- 
come, it is difficult to assess the specific impacts 
of the new technologies.— E.g., it is impossible to 
determine at this time whether technical and 
biological barriers will ever be overcome for 
regenerating wheat from protoplasts. Never- 
theless, the impact of genetics on the structure 
of American agriculture can be discussed with 
some degree of confidence. 
Genetic engineering can affect not only what 
crops can be grown, but where and how those 
crops are cultivated. Although it is a variable ii 
production, it usually acts in conjunction with 
other biological and mechanical innovations, 
whose deployment is governed by social, eco- 
nomic, and political factors. 
