1Journal article no. 5152 of the Oklahoma Agricultural Experiment Station, Oklahoma State University, Stillwater, OK 74078. This publication was supported in part by the Oklahoma Peanut Commission.
Interference of silverleaf nightshade (Solanum elaeagnifolium Cav.) with Pronto spanish peanuts (Arachis hypogaea L.) was evaluated from 1981 through 1983 in a natural occurring weed population. Treatments consisted of weed-free maintenance or weed interference for 0, 4, 8, 12 weeks and for the full season. Silverleaf nightshade stems were counted as a measure of weed regrowth in treatments maintained weed free for 0, 4, and 8 weeks. Contamination of the harvested in-shell peanuts by silverleaf nightshade berries was determined by counting the number of berries passing through the peanut combine. In-shell peanut yields were reduced by an average of 17% when silverleaf nightshade was allowed to interfere with the crop for 4 weeks. Further yield reductions of 53, 66, and 66% were observed in treatments where interference occurred for 8 and 12 weeks and for the full-season, respectively. Regression analysis conducted on yield data of individual years predicts that each week of weed-free maintenance after crop emergence results in an average of 33 to 38 kg/ha yield increase above the unweeded control. Conversely, analyses of yield data averaged over all years indicated that for each week of weed interference there would be approximately a 103 kg/ha decrease in in-shell yield compared to the weed-free control. When yield data were converted to percent of yield of weed-free controls, there was no interaction among years. Regression analysis of the converted data predicts that for each week of weed-free maintenance after crop emergence there would be a 3.7% yield increase compared to the unweeded control and that for each week of weed interference there would be a corresponding yield loss of 4.5%. Silverleaf nightshade stem counts per plot were reduced an average of 18 and 36 percent for treatments maintained weed free for 4 and 8 weeks, respectively. In 1982 analysis of fruit contamination indicated a significant difference between full-season interference and weed-free maintenance for 4 or more weeks. Differences in fruit contamination between 4, 8, and 12 weeks of weed-free maintenance were not significant. In the second year no differences in fruit contamination were observed between the weedy check and the other treatments; however, fruit production after 4 weeks of weed-free maintenance was significantly higher than after 8 and 12 weeks of weed-free maintenance. Peanut quality, disregarding contamination by silverleaf nightshade berries, was not affected by weed interference.
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Keywords: competition, Peanut yield, weed fruit production, weed dry weight
How to Cite:
Hackett, N. & Murray, D. & Weeks, D., (1987) “Interference of Silverleaf Nightshade (Solanum elaeagnifolium) on Spanish Peanuts (Arachis hypogaea)¹”, Peanut Science 14(1), p.39-41. doi: https://doi.org/10.3146/i0095-3679-14-1-10