Project Number: 6659-22000-017-00
Project Type: Appropriated

Start Date: Jun 07, 2005
End Date: Jun 06, 2010

Objective:
Investigate the role of plant growth habit and allelopathic potential on weed suppression by cole crops, sweetpotato, and watermelon, and identify vegetable crop genotypes that are competitive against weeds. Investigate the use of living and killed cover crop mulches in combination with other control measures for weed management in cole crops and sweetpotato. Select aggressive growth habit cowpea genotypes that are most suited for use as weed suppressive cover crop varieties.

Approach:
Develop and use bioassay experiments to identify allelopathic and non-allelopathic cole crop and watermelon genotypes. Evaluate allelopathic and non-allelopathic lines in field and greenhouse experiments to assess the importance of allelopathic potential on weed suppression by the crops. Utilize bioassay guided extraction and chromatography procedures to isolate allelopathic substances for identification by collaborating chemists. Develop rapid techniques to identify allelopathic genotypes using bioassays or simple chemical analyses. Survey watermelon and sweetpotato germplasm collections and identify accessions with aggressive, weed suppressing growth habit. Assess the impact of growth habit on weed interference in greenhouse and field studies. Use the knowledge attained from studies on the effect of allelopathy and growth habit on weed suppression to develop guidelines for use by plant breeders to develop genotypes that are less susceptible to weed interference. Evaluate highly allelopathic sweetpotato lines for yellow nutsedge suppression in field and greenhouse studies. Evaluate ladino clover mulch for weed suppression in sweetpotato and cowpea-sorghum cover crop mulch for weed suppression in collard and cabbage. Compare the weed suppressing ability of several cowpea genotypes in field and greenhouse experiments in order to select those most suited for use as cover crops.