Growth and Mineral Composition of Squash (Cucurbita pepo L.) as Affected by N, P, K, and Tobacco Ring Spot Virus
1967
Thomas, J. R. | McLean, D. M.
A sand culture study was conducted to measure the effects of N, P, K, and tobacco ring spot virus (TRSV) on growth and mineral composition of 'Yellow Straight Neck' squash. Concentrations of N at 56 and 224 ppm, P at 10 and 40 ppm, and K at 60 and 240 ppm were used in the presence and absence of virus. Largest dry matter yield was obtained with a nutrient solution containing the big, best concentrations of N, P, and K. Nitrogen and K significantly increased female flower formation. Increasing the nutrient N concentration raised the N content and reduced the percentage of P and K in the total plant tissue..Phosphorus increased the total and alcohol-soluble N content, whereas K decreased the total N content of the squash. The K content increased significantly as the nutrient K concentration increased. Virus reduced yields only at the high concentrations of N and P. Presence of the TRSV decreased yield response to N and P, but had no effect on yield response to K. The most striking effect of virus on squash was the decrease in the number of female flowers. Virus-induced reduction in female flower formation was greatest at the highest concentrations of N and P. TRSV significantly increased the N and P content of the squash, but had no effect on K. Virus-inoculated squash, grown in a nutrient solution containing 224 ppm N, 10 ppm P, and 240 ppm K, did not exhibit the systemic virus symptoms. Fruit produced on virus-inoculated plants grown in this nutrient solution were also free of disease symptoms.
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