Ch. 8— The Application of Genetics to Plants • 163 
and integi alfd— »' n . cnnlliil^ ili>\ elopinf; 
mauimim piiHluitn itv aiul en\ iit)mm*ntal roiut*rns 
are hv the ivinuval ol elleeti\»“ pe^tieiiles trom 
the market \pplieation> ot existing i»r ne^\ ttH hnol- 
ogies max 1 h> sereened h\ tin- piihlie loi- aeee|>tahle 
enx imnmental impact ('ontlict also «*\ists lH*txxeen 
higher pn)ductix itx and higher nutritixe lontent in 
loud. sinc»* selection Idr one often hurts the other 
8 \ critical photosvnthetic t*n/.x iue (rihulose liiphosphate 
carlM>\ l.isel is tormeil from information supplied h\ 
different genes knated iiulepeiulentlx in the chloro- 
()last la plastidt and tht' nucknis of the cell It is com- 
|M)seil of Ixxo separate protein chains that must link 
together within die chloroplasi Hie larger of these 
chains is cixled for h\ a gene in the chlomplasi— anti it 
is this gene ih.il has heen rect*nlK isolaleti and cloned 
The smaller suhunit however derives from the plant 
nucleus Itself This ctH)(H*ralion Ix'lwtHMi the nucleus 
anti the chloroplast to pititluce the functitinal expres- 
sion of a gene is an interesting phenomenon Because it 
exists, the genetics of the cell coultl he manipulatetl .so 
that cv loplasiiiicallv inlrtHlucetl genes can mfluenct' 
nuclear gene functions Perhaps mtist iiii[M)rtantlv at 
this stage, plaslitl genes are prime cantlitlales to clarify 
the basic molecular genetic merhanisms in higher 
plants 
9 rhe ativantages tti using mass pitipagation technit|ues 
for straw herrv (ilants ait* that thtise prtitluced frtim 
tissue culture are v irus-free, and a (ilantlet produced in 
tissue culture ran prixkice more shoots or runners fur 
transplanting 
rhe diiwidv antages are that during the first vear the 
fruit tends to lie smaller and. therefore, less comrner- 
ciallv acceptable: the plants from tissue culture mav 
have tmuhle adapting to soil conditions, vv hich can af- 
fect their vigor, especially during the first growing sea- 
son: and the price per plantlet ready for planting from 
tissue culture systems may lie more expensive than 
commercial prices for rooted shoots or runners bought 
in bulk. 
10. U heat protein is deficient in sev eral amino acids, in- 
cluding Ivsine. Considerable attention has been de- 
voted in the past 5 to 10 years to improv ing the nutri- 
tional properties of wheat. Thousands of lines have 
been screened for high protein, w ith good success, and 
high Iv sine genes w ith poor success. Some high protein 
varieties have been developed, but adoption by the 
farmer has been mediocre at best, partly because of 
reduced yield lev els. There are some e.xceptions;— e g., 
the \ ariety Plainsman \ ' has maintained both high 
protein and yield lev els, w hich indicates tha there is no 
consistent relationship between low protein and high 
yields in some v arieties. 
11. Some 42 percent of the total land area in the tropics, 
consisting of 1.9 billion hectares, contains significant 
forest cover. It is difficult to measure precisely the 
amount of permanent forest cov er that is being lost; 
however, it has been estimated that 40 percent of 
"closed" forest (hax ing a continuous closed canopy) has 
already been lost, with 1 to 2 percent cleared annually. 
If the highest (iredictcd rate of loss continues, half of 
the remaining closetl forest area vv ill be lost by the year 
2001).’^ rhe significance of this loss is exfiressed by 
\ormaii .Myers in his report. Conversion of Tropical 
Moist Forests, |ire|iared for the Committee on Besearch 
Priorities in I rupical Biolog^v' of the National Academy 
ol Si ience's .National Besearch Council: "Kxtrapolation 
of figures from w ell-known groups of organisms sug- 
gest that there are usually tw ice as many species in the 
tropics as teiii|)erale regions. If two-thirds of the 
Impical species oci ur in IMF (tropical moist forests), a 
reasonable extrapolation from known relationships, 
then the species of the I ,\1F should amount to some 40 
to 50 percent of the |)lanel's stock of species— or some- 
w here hetw t*en 2 million and 5 million species altogeth- 
i*r In other words, nearly half of all species on Ivarth 
are ap|)arentlv containeil in a biome that comprises 
only 0 percent of the globe's land surface. Probably no 
more than 300.000 of these species— no more than 15 
percent and possibly much less— have ever been given 
a l.atin name, and most are totally unknown. 
12 In 1975, ihe (iommiltee estimaled thal S4 million would 
be necessary for capital costs of each repository, with 
recurring annual expenses of $1,4 million for salaries 
and operalions. I'SD.A has allocaled SI. 16 million for its 
share of the construction costs for the first facility to 
be constructed at the Oregon State University in Cor- 
V allis. 
13 High yielding varielies (HV\"s) can be defined as poten- 
tially high-yielding, usually semidwarf (shorter than 
conventional), types that have been developed in na- 
tional research jirograms worldwide. Wheat varieties 
were developed by the International Maize and Wheat 
Improvement Center and rice varieties by Interna- 
tional Bice Besearch Institute. Many improved varieties 
of major crops of conventional height are not currently 
considered H\ \ types, but they have often been incor- 
porated into H\'\ breeding. HY\'s, because of biological 
and management factors, rarely reach their full 
harv est potential. 
14. .Although the National Germplasm System sucessfully 
handles some 500,000 units to meet annual germplasm 
requests, many accessions— like the 35,000 to 40,000 
wheat accessions stored at the Plant Genetics and 
Germplasm Institute at Beltsville, Md — have yet to be 
examined. Furthermore, the varieties released for sale 
by the seed companies are not presently evaluated for 
their comparative genetic differences. 
15. For comparison, the National Germplasm System func- 
tions on less than $10 million annually, whereas the En- 
dangered Species Program had a fiscal year 1980 budg- 
et of over $23 million. The funds allocated to the En- 
^^Report to the President by a U.S. Interagency Task Force on 
Tropical Forests, The World's Tropical Forests: A Policy, Strategy, 
and Program for the United States, State Department publication 
No. 9117. Washington, D.C., May, 1980. 
.Myers, Conversion of Tropical Moist Forests, report for the 
Committee on Research Priorities in Tropical Biology of the Na- 
tional Research Council, National Academy of Sciences, Washing- 
ton, D.C., 1980. 
