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.
Potato production using tissue culture in Vietnam: The status after four years
Farmers in Dalat, Vietnam, (1500 m asl) have established a unique method of using in vitro plants as a source for planting material (1). The rapid adoption of this approach was attributed to several factors. Farmers had been using degenerated seed of cultivars susceptible to Phytophthora infestans, resulting in low yields and decreasing area under cultivation. Three new high yielding cultivars were introduced as clones: CFK 69.1, B71-240.2 and Atzimba and were named as V4, V8 and VI2, respectively after having shown good P. infestans resistance and given high yields. No seed tubers were available for these new cultivars. This communicat ion reports the evolution of the demand for and use of cutting technology in the spread of these new cultivars f rom late 1980 to late 1984.
Increased tuberization in potatoes by ethrel (2-chloro-ethyl-phosphonic acid)
SummaryDoses between 25 and 500 ppm. of ethrel strikingly increased the initiation of potato tubers when they were supplied before natural tuberization. Treatments after that moment were somewhat less effective. Enhanced epinasty and leaf abscission were also observed following ethrel applications.