A Preliminary Study on Systems Engineering-Based Method for the Evaluation of Allelopathic Potential in Crops and Its Application

The objective of this study was to develop a method to assess and analyze the total allelopathic potential of crop germplasm and to test this method on four winter wheat accessions commonly planted in the Loess Plateau. A systems engineering model was developed and used to evaluate the total allelopathic potential of crop cultivars. In addition, a method for quantifying the total allelopathic potential in crop accessions was presented. Total allelopathic potential of four winter wheat accessions from the Loess Plateau was estimated and compared using a systems theory approach. The model assessed allelopathic potential in different parts of the plants from the time wheat turned green in spring until maturity. Results from these models indicated that the four wheat accessions had very weak allelopathic potential. Allelopathic potential declined in the order Xiaoyan 22 〉 Ningdong 1 〉 Fengchan 3 〉 Bima 1. This system engineering evaluation method allows for the assessment of allelopathic potential among crop varieties. It will help plant breeders to select and develop allelopathic crop accessions that combine weed suppression properties with agronomic traits related to yield and quality.

Studies on the Allelopathic Potential of Corn （Zea mays L.） Aqueous Extracts and Root Exudates

This investigation was carried out at Faculty of Agriculture and Forestry-University of Duhok/Kurdistan-Iraq. Three experiments were included in this investigation： （1） First experiment was a bioassay related to the germination performance, shoot and root development of corn （Zea mays L.） and peanut （Arachishypogaea） at two concentrations of root （3% and 1.5%） and shoot （12% and 6%） aqueous extracts of corn medium; （2） The second experiment dedicated to the intercropping of corn and peanut at four treatments; （3） While the third experiment involved the effect of peanut root exudation on growth of corn. Experiment results revealed that corn shoot and root water extracts highly inhibited seed germination of both corn and peanut, the inhibitory of shoot extract was more than root aqueous extract. While its effect on the seedling growth was vice versa as compared with control treatment, there was an increase in root and shoot length of both corn and peanut when grown in corn aqueous extracts. Intercropping experiment results has stimulated most traits of peanut under studying. Also for corn, there was apparent and significant increase in all characteristics as compared with control. It was further confirmed from the results of peanut root exudates that had all studied characters of corn were stimulated than the control treatment.

A New Bioassay Method for Evaluation Allelopathic Potential of Rice Germplasm

Allelopathy was defined in 1996 by IAS （international allelopathy society） as any process involving secondary metabolites produced by plant, algae, bacteria and fungi that influences the growth and development of agricultural and biological systems. Rice allelopathy against weeds was reported since 1989, which offers an integrated weed management with substantially reduced herbicide usage. Application of allelopathic rice cultivars is thought a resources conservation and environmental friendly way of weed bio-control, and could promote the sustainable development of agriculture. Screening or evaluating the allelopathic potential rice variety is the first step. In this paper, a new bioassay method was set up by the allelopathic potential of 9 rice lines on the target weed barnyardgrass （Echinochloa crusgalli）, and comparing with bioassay methods such as relay seeding in filter paper （RSF） and relay seeding in agar （RSA）. The results indicated that three methods had a same tendency in evaluating the allelopathic potential of rice; there existed a significant difference among different bioassay methods, and an interaction between bioassay methods and rice lines. The method of root exudates （RE） with the highest value and a correlation efficiency of 0.98 was considered as ideal bioassay method for evaluation of allelopathic potential.

Allelopathic potentials of surrounding vegetation on seedling establishment of alpine cushion Arenaria polytrichoides Edgew

When facilitating other species and sustaining plant community structures and biodiversity,alpine cushion plants simultaneously experience negative feedback effects from surrounding vegetation.However,the impact of surrounding vegetation on cushion dynamics remains poorly understood,particularly in terms of allelopathic potentials.To investigate the allelopathic potentials of surrounding vegetation on seedling establishment of the typical cushion plant Arenaria polytrichoides Edgew.along an elevational gradient,we extracted potential allelopathic compounds and tested their impacts on seed germination and seedling growth of A.polytrichoides.In addition,exclusion experiments using activated carbon were conducted to further elucidate these effects.Our results demonstrate that surrounding vegetation exhibits certain allelopathic potentials on A.polytrichoides seedling establishment,with variations observed based on elevation,source and concentration of allelopathy compounds,as well as growing season.Specifcally,low-elevation vegetation exerts pronounced suppression on seedling establishment.Conversely,higher-elevation vegetation generally shows no effect on seed germination but stimulates seedling growth through allelopathy mechanisms.Moreover,aboveground vegetation predominantly inhibits both seed germination and seedling growth in low-elevation communities;however,the effects of belowground vegetation depend on elevation and extract concentration levels.The identifed allelopathic potentials of surrounding vegetation signifcantly infuence the population dynamics of cushion A.polytrichoides by potentially accelerating population degeneration in lower-elevation communities while ensuring consistent population recruitment and expansion in higher-elevation communities.