PART VII — WATER RESOURCES, FORESTRV AND AGRICULTURE 



or leaching — poses added problems 

 for hydrologists and engineers. But 

 these areas of science and technology 

 are useless unless they are used in 

 adequate systems of agronomy, in- 

 volving knowledge of soil chemistry, 

 soil physics, plant physiology, plant 

 genetics, and soil-plant-water rela- 

 tionships in every microclimate where 

 crop plants are grown. 



Science basic to optimal use of 

 solar energy and science basic to 

 effective use of fossil fuel or other 

 energy source in crop production, 

 transportation, and storage and proc- 

 essing of food crops is essential. In 

 many countries, fossil fuel must be 

 imported while human labor is in 

 oversupply. Since a man is equivalent 

 only to about one-eighth horsepower, 

 it is difficult, if not impossible, to use 

 enough human labor at the precise 

 time when planting, harvesting, or 

 cultivation is required. 



Crop-Plant Genetics and Breeding 



— Genetic capacity of crop plants 



and livestock species for the produc- 



tion of food useful and acceptable to 

 man is a first requirement. Comes 

 then the question of whether native 

 plants and animals developed in and 

 adapted to the many niches of a local 

 ecosystem are better suited to serve 

 man's needs there than those intro- 

 duced from other places? 



The answer is that, for subsistence 

 agriculture, the native varieties have 

 many advantages. Natural selection 

 over many generations has enabled 

 them to survive the pests and com- 

 peting organisms of their area of 

 origin. But often this adaptation en- 

 ables them to survive with only a 

 meager excess for man's use. 



When man brings a new seed from 

 a far place, it often fails in the new 

 location; but not always. If it hap- 

 pens to be adapted to the new loca- 

 tion it may thrive there in the ab- 

 sences of the diseases and pests it 

 has left behind. Thus, sunflowers 

 thrive in Hungary and the Ukraine 

 while they are little exploited in their 

 native Kansas, where they are weeds 



beset with many enemies. So, too, 

 soybeans thrive in Illinois — far from 

 their native China. Figure VII-9 

 shows two other transplanted species. 



Selection, sometimes rather simple 

 phenotypic selection, has developed 

 crop plant variants used in various 

 parts of the world that are often pre- 

 ferred for organoleptic quality though 

 inferior in productivity. "Baking 

 quality" in bread wheat is not useful 

 in macaroni wheats, for example. 

 Phenotypic selection continues to be 

 an important crop-breeding tool. 



Science basic to plant breeding has 

 contributed (a) controlled methods of 

 hybridization that have added yield 

 to some crop plants, especially maize; 



(b) dwarfism, which has made possi- 

 ble dramatic yield increases through 

 response to heavy fertilizer and water 

 applications without lodging, espe- 

 cially in rice, wheat, and sorghum; 



(c) genetic disease resistance, espe- 

 cially resistance in wheat to rust; and 



(d) selective breeding for photoperiod 



Figure VII-9 — TRANSPLANTED SPECIES 



HEVEA RUBBER (HEVEA BRASILIENSIS) 

 I Area of Origin 



JHH| Area of Transplanted Species 



COFFEE (COFFEA ARABICA) 

 | Area of Origin 

 II Area of Transplanted Species 



"0 



S 



J? 



The map shows the area of origin of coffee (Coffea arabica) and hevea rubber 

 (Hevea brasiliensis) and the areas where, having been transplanted, they are now 

 principally cultivated. In its place of origin, coffee is subject to native red rust 

 (Hemilaea vastatrix), whereas in the New World, no native diseases exist. Hevea 

 rubber is found in the New World only in the wild. In the Old World, where major 

 production takes place today, there are no native pests. 



216 



