A novel laboratory screening bioassay for crop seedling allelopathy

Area of Science:

• Agricultural Science
• Plant Science
• Biochemistry

Background:

• Allelopathic crops, which suppress weeds via root exudates, are gaining importance.
• Breeding for these traits requires identifying germplasm with high allelopathic activity.
• Current laboratory screening protocols for allelopathy are limited.

Purpose of the Study:

• To develop a fast, reliable laboratory bioassay for screening grain crops for allelopathic traits.
• To incorporate dose-response elements into the experimental design.
• To optimize the protocol using known allelochemicals and crop species.

Main Methods:

• Hydroponic culture bioassay using Sinapis alba L. as the receiver species.
• Experiments with 2-(3H)-benzoxazolinone (BOA) to define protocol parameters.
• Testing Secale cereale L. and Triticum aestivum L. as donor species to optimize the assay.

Main Results:

• Root length was the most reliable indicator of BOA's inhibitory effect on growth.
• BOA impacted plant growth, enzyme activities, and chlorophyll fluorescence.
• Nutrient availability significantly influenced BOA sensitivity, necessitating nutrient omission in the assay.

Conclusions:

• The developed hydroponic bioassay is a fast and reliable method for identifying allelopathic germplasm in grain crops.
• The assay effectively incorporates dose-response considerations and minimizes confounding factors like light and pH.
• This improved screening method facilitates the genetic improvement of crops for natural weed control.