RESPONSES OF SOME SUGARCANE VARIETIES TO STANDARD AND COMBINATION RIPENER TREATMENTS
The effects on sucrose yield of varying the time interval between Ethrel and Fusilade Super applications in a com­ bination treatment were tested on variety NC0376. Results suggested that Ethrel applied 12 weeks, and Fusilade Super applied eight weeks before harvesting were the most bene­ ficial. Other varieties which responded to a combination treatment were N19, N12 and N22. Varieties N14, N19, N17, N12, N22 and NC0376 grown under irrigation all re­ sponded to one of the ripener treatments, and their responses to Ethrel and Fusilade Super are discussed. There were no significant gains in sucrose yield of CP66/1043 in response to the ripeners although sucrose content was increased.
Crop physiology: A perspective for southern Africa
Crop physiology is a broad subject and a comprehensive treatise of all its aspects is impossible, even in a whole volume dedicated to the subject. With a few exceptions, plant physiology, rather than crop physiology, is commonly the focus when physiological aspects of plant growth and development are reviewed in biological sciences. Plant and crop physiology are distinguishable by the manner in which one is almost purely basic and the other tends towards application of the science in crop management. Therefore, the objective of this review was to highlight crop production-oriented physiological research that has shaped our current knowledge and research activities in the past few decades, especially the latter part of the past century. Source-sink relationships, stress physiology, mineral nutrition and seed physiology were identified as the key aspects of crop physiology that influence crop production. Each of these aspects is addressed to identify its significance in crop performance and to highlight both the breakthroughs and gaps in our contemporary knowledge of crop physiology. There was no attempt to provide fundamental interpretations. The reader is referred to relevant appraisals of crop and plant physiology, to gain further insight into original data. Since the review is also meant to contribute to further education in crop production, views on the challenge of training future crop scientists are expressed in the final section.
Practical, legal, and ethical issues in expanded access to investigational drugs.
The authors review the FDA policies and procedures that permit some patients with serious conditions to receive investigational drugs before formal product approval and examine the legal and ethical issues associated with expanded access.