predicted by similar use of modeling techniques 

 and the impact upon plant development predicted. 

 With anticipated events, manageable inputs may 

 be altered to improve production efficiency. 



The mathematical modeling techniques are 

 providing a new systems management capability 

 for more efficient production of crops. Optimum 

 applications of fertilizer, water, and pesticides are 

 being determined with more efficient utilization of 

 energy and nutrients and maximized productivity. 



Hesketh. J. D., D. N. Baker, and W. G. Duncan. 1972. The 

 simulation of growth and yield in cotton: II environmental 

 control of morphogenesis. Crop Sci. 12:4.16-9. 



Hesketh. J. D.. J. M. McKinion, J. W. Jones, and D. N. Bak- 

 er. 1974. Problems in modeling photosynthesis and respiration. 

 Rnvironmental and biological control of photosynthesis. Bel- 

 gium. Aug., 1974. 



Jones. J. W. and B. P. Verma. 1971. A digital simulation of 

 the dynamic soil moisture status. Transactions ASAE 14 (4) 

 h60-fi64. 



Jones, J. W.. J. D. Hesketh, E. J. Kamprath, H. D. Bowen. 

 1974. Development of a nitrogen balance for cotton growth 

 models: A first approximation. Crop Sci. l4:.'^41-6. 



McKinion, J. M., D N Baker. J. D. Hesketh. and J. W. 

 Jones. I97.'i. SIMCOTT II: A simulation of cotton growth and 

 yield. Computer simulation of a cotton production system, 

 users manual. ARS-S-52. 



Wanjura, D. F., D. R. Buxton, and H. N. Stapleton. I97.V A 

 model for describing cotton growth during emergence. Transac- 

 tions ASAE, l6(2):227-2.tl. 



Storage Life of Food Crops 



Extending the storage life of food crops with 

 retention of quality and nutritive characteristics 

 requires understanding of both postharvest phy- 

 siology and mechanisms by which biological dete- 

 rioration occur. Refrigeration has been the classi- 

 cal procedure for extending storage life: but other 

 techniques such as manipulating and controlling 

 the storage atmosphere, and hot-water and fungi- 

 cide treatments are also proving effective. A new 

 departure, still in the basic research stage, is the 

 use of bioregulators. 



Abdul-Baki, A. A., and J. E. Baker. 197.1. Are changes in cel- 

 lular organelles or membranes related to vigor loss in seeds? 

 Seed Sci. and Tech., 1:89-125. 



Harvey, J. M., and Harris, C. M. 1975. Market quality in rela- 

 tion to postharvest handling and shipping practices. ASHRAE 

 J., 15:35 (abstract). 



Lieberman, M. 1975. Biosynthesis and regulatory control of 

 ethylene in fruit ripening. Physiologia Vegetale, 13:489-499. 



Poling, S. M.. W. J. Howard, and H. Yokoyama. 1975. 

 Structural activity relationship of chemical inducers of caro- 

 tenoid biosynthesis. Phytochemistry 14:1933-1938. 



Smith, Jr., W. L. 1973. Quality maintenance of fruits and veg- 

 etables. U.S. Dept. of Commerce, Maritime Admin. Conf. 

 Rpt. on refrigerated containers. 54-60. 



Fungal Genetics of Forest Tree Pathogens 



The objective of forest disease research is to 

 modify host or pathogen as necessary to make 

 them incompatible. Work with tree rusts has in- 

 volved some of the major efforts to control dis- 

 eases by modifying the genetic constituency of 

 host or pathogen. Research on white pine blister 

 rust, an introduced disease, has yielded informa- 

 tion from which scientists have been able to struc- 

 ture a program for controlling infections. Critical 

 to the success of this program was a fundamental 

 knowledge of fungus variation and variability of 

 host resistance to infection. Research efforts have 

 also yielded information that will permit limiting 

 the effects of fusiform rust, the most serious dis- 

 ease of southern pines. Recent research on patho- 

 genic variability, when coupled with knowledge of 

 host resistance, dictates the kind of program most 

 appropriate for controllong this disease. 



Bingham, R. T., R. J. HofT, and G. I. McDonald. 1971. 

 Disease resistance in trees. Ann. Rev. Phytopath. 9:433-452. 



Snow, G. A.. R. J. Dinus, and A. G. Kais. 1975. Variation in 

 pathogenicity of diverse sources of Cronartium fusiformae on 

 selected slash pine families. Phytopath. 65:170-175. 



Snow, G. A., R. J. Dinus, and C. H. Walkinshaw. 1976. In- 

 crease in virulence of Cronartium fusiformae on resistant slash 

 pine. Phytopath. 66:511-513. 



Wood Growth and Differentiation 



To understand the basic properties of wood 

 formation there must be an in-depth understand- 

 ing of the physiological processes that control the 

 growth and differentiation of wood elements in 

 forest trees. Research on hormonal regulation of 

 wood has contributed to the clarification of early- 

 wood-latewood transition, reaction wood forma- 

 tion, branching angle, stem form, and taper. In 

 the course of these investigations it was clearly 

 demonstrated that the anatomical development 

 was a limiting factor in both photosynthesis and 

 the translocation of assimilates; thus, photosyn- 

 thetic rates alone did not control growth rate or 

 wood formation. 



Larson, P. R. 1969. Wood formation and the concept of wood 

 quality Yale Univ. School of Forestry Bulletin No. 74:54p. 



Larson, P. R. 1976. Development and organization of the sec- 

 ondary vessel system in Populus grandidentata. Amer. J. Bot. 

 63:369-381. 



Nutrient Cycling in Forest Ecosystems 



Insects and fungi serve as vital links that contri- 

 bute to diversity and long-term ecological devel- 

 opment of forest communities. These agents are 

 energy-efficient consumers contributing to the 

 breakdown of organic matter, demise of aged and 

 inefficient plants, hastening of forest succession, 



AGRICULTURE 1 3 



