Influence of Virginia Market Type Genotype on Peanut Response to Weed Interference

Abstract

Differences in the ability of cultivars to compete with weeds are not well-defined for peanut. Research was conducted in 2007 and 2008 to compare the growth and competitiveness of the virginia market type cultivars NC 10C, NC-V 11, NC 12C, Phillips, VA 98R, and breeding lines N99027L, N01013T, and N02020J under weedy and weed-free conditions. Weed-free peanut was established by applying preemergence and postemergence herbicides throughout the growing season supplemented by weekly hand removal of weeds. Clethodim was applied to weedy peanut to eliminate annual grass interference but not interference from broadleaf weeds and sedges. Weed-free peanut biomass, weedy peanut biomass, and weed biomass were not affected by genotype 10 weeks after peanut emergence. Although substantial yield loss was noted in presence of weeds, the percent yield loss did not vary by genotype when comparing weedy and weed-free yield. These data suggest that cultivar selection within virginia market type peanut will have limited utility in a comprehensive weed management strategy.

Peanut Cultivars Differing in Growth Habit and Canopy Architecture Respond Similarly to Weed Interference

“…The results indicated that despite their differences in growth habit and canopy architecture, the four evaluated cultivars responded similarly to weed interference (Table 1). Place et al (2012) compared biomass production of eight Virginia market type peanut genotypes growing under weed-free and weedy conditions, but all genotypes responded similarly to weed interference. They concluded that, at least for Virginia market type peanut, efforts to select cultivars with higher weed suppression and competition tolerance might have little value as part of an integrated weed management approach due to the limited genetic variability for these traits.…”

“…Therefore, efforts to increase competitive tolerance to weeds should emphasize experimental approaches that allow characterization of peanut sensitivity to weed interference. However, it might be necessary to evaluate peanut types other than those studied in the present research and by Place et al (2012) to increase the likelihood of finding genetic material with higher potential for weed suppression and interference tolerance…”

“…trifoliates), total leaf area, and plant dry weight were determined. Before harvest, weedy plots were mowed above the peanut canopy and hand weeded if needed to avoid pod loss during harvest (Place et al, 2012). The two middle rows of each plot were dug with a conventional digger-shaker-inverter and were allowed to air-dry in the field for 5 to 7 d. Peanut was then picked with a two-row peanut combine and yield was determined at 10% moisture.…”

“…Peanut-weed interference has been studied to characterize potential yield loss, to determine optimum planting arrangements, and the critical period of competition when weed control actions are most needed (Agostinho et al, 2006;Hauser et al, 1975;Hauser and Buchanan, 1981;Place et al, 2010). Place et al (2012) compared the response to weed interference of eight Virginia market type genotypes without finding clear differences among genotypes. However, all genotypes suffered significant yield losses resulting from weed interference.…”

“…However, all genotypes suffered significant yield losses resulting from weed interference. With the exception of the Place et al (2012) study, which focused on peanut biomass and yield responses, there is no information about which morphological characteristics and changes in canopy architecture favor peanut weed suppressive ability and the variability among peanut cultivars to tolerate weed interference. The objectives of the present study were: 1) to determine whether peanut cultivars with different canopy architecture and growth habit differ in their weed suppressive ability and weed interference tolerance, and 2) to characterize morphological and physiological responses to differing levels of weed interference.…”