The vegetative growth in the four treatments in which mulch was removed and renewed every 3, 6, and 9 months, plus the control where it was not renewed at all, was 136.47 feet, 133.75, 158.00, and 174.92 feet, respectively. This experiment demonstrates that removal of mulch is detrimental rather than beneficial. Mulch should be replaced rather than removed as it decomposes.
Vanilla Hybrids. H. J. Cruzado and A. J. Loustalot
Seed of crosses between Vanilla fragrans (Salisb.) Ames X V. phaeantha Reichb. f. were germinated at Cornell University by Dr. Lewis Knudson in January 1947 and sent to this station for propagation. They were grown in 3-inch pots in the greenhouse until October 1948, when they were of sufficient size for transplanting to the field. Of a total of 40 hybrids, 37 were transplanted to a lath-shade house, and most of these are making good growth. Because of the resistance of the V. phaeantha parent to vanilla root rot and drought it is hoped that these characteristics, along with good fruit quality, will be carried over into the hybrids.
Physiological Experiments. A. J. Loustalot and H. R. Cibes
Vanilla vines were grown in two gravel culture experiments: One with three levels of nitrogen (3, 10, and 81 p. p. m.) and three levels of potassium (0, 7, and 40 p. p. m.), and the other with 3, 27, and 81 p. p. m. of nitrogen and 0, 5, and 27 p. p. m. of phosphorus in factorial combinations. The low level of nitrogen in both experiments had a profound depressing effect on growth. The low potassium level had depressing effect on growth, but to a lesser extent than nitrogen. An increase in the level of either N or K resulted in an increase in the growth of the vines. The best growth was obtained with the highest N-K level.
The N and K contents of the vines were directly correlated with levels at which these elements were supplied. The percentage of Ca and Mg in the leaves was inversely correlated with the potassium content. The low phosphorus level depressed growth primarily when nitrogen was low. The nitrogen and phosphorus contents of the vines was directly correlated with the levels at which these elements were applied. At all nitrogen levels the percentage of nitrogen in the leaves decreased as the phosphorus percentage (or supply) increased.
Vanilla Curing. C. F. Cernuda and R. Fernández Pol An experiment was conducted to determine the effect of various oxygen levels during conditioning on the quality of cured vanilla. Oxygen equivalents of 20, 15, 10, 5, and 0 percent were established in bottles containing the vanilla beans for conditioning. Extracts from the various treatments were tested in milk.
It was found that extracts made from the vanilla conditioned at the 20 percent O₂ level in all three ages of conditioning gave the best flavor, followed by those conditioned at 15 percent O₂ level. No difference could be detected between the extracts made from beans conditioned with 10 and 5 percent O₂. The samples conditioned at zero O₂ made the poorest extracts. The vanillin in the samples stored at 0, 5, and 10 percent oxygen increased with the conditioning time. The percent vanillin for the samples stored with 15 and 20 percent oxygen was the highest when the conditioning time was 3½ months.
