Techniques for using sprouts for potato production in the tropics
A series of experiments were conducted in Vietnam to develop a system whereby detached sprouts from physiologically old green sprouted seed tubers could be used to grow potatoes. Three node segments from the mid or basal portion of the detached sprout produced the greatest percentage of shoots and roots. Growth was best in a medium of equal parts of sub-soil, pig manure and brick kiln ash. Sprout cuttings produced plantlets ready for transplanting in 14–20 days with mean daily temperatures of 22 to 24°C. When transplanted in mid-November, yields from sprout cuttings in field experiments were 10 to 18 t/ha which were 33% lower than from healthy seed tubers but more than the national average yield using degenerated seed tubers. Tubers produced by plants grown from sprout stored well and gave good yields when replanted the following year.
Effects of growth regulators on the growth and yield of detached and transplanted potato (Solanum tuberosum L.) sprouts
SummaryRoots of 15-day-old sprouts detached from tubers of potato (Solanum tuberosum L.) cv., Local Red, were dipped for 1 min in a 0.25% solution of Ethrel (ethephon), Rootone-F (RF), or Transplantone (TP) or in water and then planted in the field. Plants treated with RF and TP were significantly (P<0.05) taller, had heavier haulm, produced more leaves, and yielded more tubers than those of the control treatment with water, ethephon had no effect. RF was significantly (P<0.05) superior to TP for all measured components except leaf number.
An Essay on the Nature and Significance of the Normative Nature of Economics
It is conventional in economics to distinguish between the normative and the positive. The normative has to do with goodness and badness, and with what ought and ought not to be done;1 and the positive has to do with objective description and/or explanation, with what is and with what is necessary given some normative end. The normative has to do with desirability; the positive has to do with truth (in the sense of either descriptive accuracy or serviceability of a means to a given end).2