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Effect of Population Levels on Growth Factors in Kenaf Varieties

White, G. A., Adamson, W. C., Higgins, J. J.
Agronomy journal 1971 v.63 no.2 pp. 233-235
botany, Plant Science and Plant Products
The response of seven varieties of kenaf (Hibiscus cannabinus L.), a potential new paper-pulp crop, to population levels of 99,000, 198,000, and 296,000 plants/ha was studied at Glenn Dale, Md., and Savannah, Ga. Populations affected plant height, stem diameter, and yield more than varieties. As the population level increased, plant height and basal stem diameter significantly decreased and percent dry matter at harvest increased. The cultivar ‘Cubano’ usually was significantly higher in percent dry matter at harvest than other varieties. The initial population of 99,000 plants/ha remained essentially unchanged at harvest, but reductions of about 9 and 20% occurred for initial populations of 198,000 and 296,000 plants/ha, respectively. The varieties ‘SH/15R’, Cubano, and ‘C-2032’ sustained the most severe stand reduction. Stem yields generally increased as population increased. Yield means for populations at Savannah did not differ. At Glenn Dale, data showed a significant yield advantage in 1968 of 296,000 plants over lower population levels. In 1969, the mean yield of 12.5 mt/ha for populations of 198,000 and 296,000 plants significantly exceeded the 11.1 mt/ha yield for 99,000 plants. In general, varietal differences and variety-population interactions for height, stem diameter, and yield showed minor significance. ‘Ev71’ and SH/15R were usually the highest yielding varieties. The highest disease incidence occurred on Cubano, ‘BG52-75’ and SH/15R.