Page:Report of the Puerto Rico Experiment Station (IA CAT31294391015).pdf/11

 alkaloid and quinine content. With some exceptions, the results of the 1948 analyses were similar to those of the two previous years. There was no consistent correlation between vigor, as measured by height of tree, with total alkaloids and quinine content.

The percentage of quinine in the roots and lower trunk bark ranged from 6.45 percent to 2.29 percent, and in the upper trunk bark from 2.43 percent to 0.58 percent. There was a tendency for the amount of quinine in the roots and upper trunk bark to be correlated with that in the lower trunk bark. The quinine content of all tissues was generally lower in 1948 than in 1947. The percentage of total alkaloids in the roots was correlated with that in the lower trunk bark and this was also true, but to a lesser extent, with the total alkaloids in the upper trunk bark. The percentage of total alkaloids was also lower in all tissues in 1948 than in 1947.

H. E. Warmke, H. J. Cruzado, R. M. Smith, and E. A. Telford

An experiment was conducted to test the feasibility of producing vegetable crops on established, hand-cut terraces, using tropical kudzu to stabilize the banks. Tomatoes were grown without added organic matter, with filter press cake ("cachaza") worked into hills immediately before planting, and with the kudzu trash from the terraces worked into the hills immediately before planting. Plants with kudzu trash worked into the hills before planting were more vigorous and produced more marketable fruit than either the controls or the cachaza-treated plants. The addition of improved the plant color and caused a slight increase in average yield in all treatments. Cachaza, a byproduct of sugar manufacture, is widely used as a soil amendment on the island, and its detrimental effect in this experiment was unexpected. A possible explanation was an outbreak of bacterial wilt to which the cachaza-treated plants seemed especially susceptible.

H. E. Warmke and H. J. Cruzado

Forty-three Mayagiiez selections from hybrids between native and imported tomato varieties, grown during the months of June to September, produced an average of over 2.5 times as much marketable fruit as did the standard varieties, Marglobe and Michigan State Forcing. The 10 best hybrids produced an average of 1.58 pounds per plant, or over 4 times the average of the imported varieties and the best hybrid produced 2.10 pounds, or nearly 5 times as much as Marglobe, the best imported variety in these trials.

Stocks showing some resistance to bacterial wilt were selected and grown in a replicated experiment in a field known to be heavily infested with this organism. Yields from all lines in this field were very low (because of severe infection), but the Mayagüez selections outyielded all of the imported or native varieties. Further tests will be necessary to determine if this resistance is sufficient to make it of commercial value.