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The root growth rate index of velvetleaf (Abutilon theophrasti Medic.) was significantly greater than that of five other weed species. The root growth rate index of sorghum [Sorghum bicolor (L.) Moench 'RS-626'] was found to be significantly higher than that of soybeans [Glycine max (L.) Merr. 'Ford']. Shoot growth rate indexes of three perennial broadleaf species studied were significantly lower than shoot growth rate indexes of six annual species. Root weights of perennial broadleaf species were not significantly different from root weights of velvetleaf and soybeans. Soybeans were found to have a significantly higher shoot to root ratio than seven weed species but not higher than sorghum. All other species had larger leaf weights and leaf areas than the three broadleaf perennials. While there were significant differences in leaf weights among six species, there were no significant differences in leaf area. Seed weight was not significantly correlated with emergence rate index and root weight but was correlated to all other factors studied. Emergence rate index was correlated with root growth rate index but not with shoot growth rate index.
Weed Science © 1973 Weed Science Society of America