ARS | Publication request: COMPARISON OF THREE PARAMETERS FOR ESTIMATION OF ALLELOPATHIC POTENTIAL IN SWEETPOTATO [IPOMOEA BATATAS (L.) LAM.] GERMPLASM

Submitted to: Allelopathy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 11, 1999
Publication Date: N/A

Interpretive Summary: Sweetpotatoes have the ability to suppress growth of weeds around them. This is accomplished by the production and release of certain chemicals which are synthesized in the skin of the roots and tuber. This trait is highly desirable, since it reduces the use of herbicides significantly. The content of these chemicals varies greatly between the various sweetpotato cultivars and breeding populations. Eleven genetically diverse sweetpotato clones were tested for their weed suppressing potential. Three different types of assays were used for evaluation and all three assays identified the same three strongest clones. The most efficient and cheapest method involved semi-automated chemical analysis for the responsible compounds. This analysis allows rapid selection of plant material for breeding purposes and results in greatly accelerated and quantitative breeding for this property.

Technical Abstract: Eleven sweetpotato [Ipomoea batatas (L.) Lam.] germplasm sources, primarily cultivars, were tested for allelopathic potential. Three parameters were used for estimation: suppression of yellow nutsedge (Cyperus esculentus L.) growth and development, inhibition of prosomillet (Panicum milliaceum L.) seed germination by methanolic extracts of storage root periderm tissue and quantitative determination of resin glycoside content of storage root periderm tissue. The three methods identified the same three clones with the strongest potential i.e. 'Excel', 'Regal' and 'Sumor'. The seed germination bioassays are useful if equipment is not available. They gave good results and are easiest to perform. However, much time is required since the experiments have to be performed several times. Quantitative determination of resin glycoside content, using HPLC methods, is recommended. This method is inexpensive, fast and adaptable to automation and therefore is best suited for routine evaluation of large numbers of sweetpotato seedlings generated routinely in breeding programs.