ASSESSING THE ALLELOPATHIC INTERACTION BETWEEN .ASSESSING THE ALLELOPATHIC INTERACTION BETWEEN WINTER

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  • ASSESSING THE ALLELOPATHIC INTERACTION BETWEEN WINTER CEREALS AND WEEDS

    Bachelor’s thesis (15 ECTS) in Agrobiology, summer 2016

    – Plant and Environmental Science, Department of Agroecology, Aarhus University

    Peter Liebing Grøngaard, 201304252

    Supervisor: Per Kudsk, professor at Department of Agroecology – Crop Health

    Co-supervisor: Antje Reiss, Ph.D.-student at Department of Agroecology – Crop Health

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    Sammendrag

    Ukrudt er et alvorligt problem i moderne landbrugsproduktion, og betegnes som en af de

    væsentligste årsager til udbyttetab i dyrkningen af vintersåede kornafgrøder. Dermed er

    bekæmpelse af ukrudt en væsentlig del af producenternes arbejde med afgrøderne, og

    afhængigt af ukrudtsbestanden, kan bekæmpelsen være meget kostbar.

    I konventionelt landbrug bruges syntetiske herbicider som en del af en effektiv praksis til at

    slå ukrudtsplanter ihjel. På grund af en stadigt mindre gruppe af herbicider, der er

    tilgængelige for producenterne, er der større risiko for udvikling af resistens mod midlerne i

    ukrudtsbestandene. For at opretholde bekæmpelsen og til at supplere sprøjtningen med

    herbicider, er der fra EU’s side fokus på at anvende IPM – Integrated Pest Management –

    hvor blandt andet afgrødernes naturlige undertrykkelse af ukrudt kan anvendes.

    I dette bachelorprojekt undersøges, i hvilken grad det er muligt at påvise en

    ukrudtsundertrykkende effekt af seks kornsorter på to almindelige ukrudtsarter. I kraft af den

    anvendte metode undersøges afgrødernes allelopati – den del af undertrykkelsen der foregår

    via afgrødernes sekundære metabolitter.

    Det var muligt at påvise forskelle imellem sorter af samme art på deres inhibering af

    rodvæksten i ukrudtsplanterne. Der var ligeledes forskel på, i hvor høj grad de forskellige

    arter inhiberede rodvæksten.

    Forsøget viste ingen indikation på, at nogle af kornsorterne skulle yde negativ indflydelse på

    skudvæksten i ukrudtsplanterne.

    Abstract

    Weeds represent a serious challenge to modern farmers, being recognized as one of the major

    reasons for crop losses in general, and in winter cereals in particular. Thus, weed

    management takes up a substantial part of the farmer’s workload, and depending on the

    density of weeds, can also be a significant economical expense.

    Conventional farmers use synthetic herbicides to effectively combat weeds. The risk of

    developing herbicide-resistant weed populations is increased by an ever decreasing choice of

    herbicides available to farmers. In order to keep weeds in check and to supplement herbicide-

  • Side 1 of 34

    spraying, the EU is urging its member states to implement measures of Integrated Pest

    Management. One of these measures may be the inherent ability of crops to suppress weeds.

    This bachelor’s thesis seeks to investigate the extent to which six cultivars of winter sown

    cereals are able to suppress two common weed species. The method applied in this study

    allows for the examination of the crop cultivars’ allelopathy – the part of weed suppression

    mediated by plant secondary metabolites.

    It was possible to detect differential inhibition of root growth between cultivars of the same

    cereal species. Different inhibition of root growth between cereal species was also detected.

    However, there was no indication that any of the tested cereal cultivars had a negative

    influence in the shoot growth of the weed species.

    Peter Liebing Grøngaard – 15/08-2016

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    Indhold

    Sammendrag .............................................................................................................................. 0

    Abstract ...................................................................................................................................... 0

    Indhold ....................................................................................................................................... 2

    1. Introduktion........................................................................................................................ 4

    1.1. Problemformulering .................................................................................................... 5

    1.2. Hypoteser .................................................................................................................... 6

    2. Teori ................................................................................................................................... 7

    2.1. Allelopati ..................................................................................................................... 7

    2.2. Kornarter ..................................................................................................................... 8

    2.2.1. Hvede ................................................................................................................... 8

    2.2.2. Rug ....................................................................................................................... 9

    2.2.3. Triticale .............................................................................................................. 10

    2.3. Ukrudt........................................................................................................................ 11

    2.3.1. Agerrævehale ..................................................................................................... 11

    2.3.2. Lugtløs Kamille ................................................................................................. 11

    2.3.3. Herbicidresistens ................................................................................................ 12

    2.4. Interaktion ................................................................................................................. 12

    3. Materialer og metode ....................................................................................................... 13

    3.1. ECAM ....................................................................................................................... 13

    3.1.1 Valg af metode ................................................................................................... 13

    3.1.2. Materialer ........................................................................................................... 13

    3.1.3. Plantemateriale ................................................................................................... 14

    3.1.4. Vækstmedie og bægerglas ................................................................................. 14

    3.1.5. Kontrolgruppe .................................................................................................... 15

    3.2. Udførelse ................................................................................................................... 15

    3.3. Indsamling af data ..................................................................................................... 17

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    3.4. Databehandling.......................................................................................................... 18

    3.4.1. Statistisk metode .................................................................................................... 18

    3.4.2. Multiple comparison .......................................................................................... 20

    4. Resultater ......................................................................................................................... 21

    4.1. Agerrævehale ............................................................................................................ 22

    4.1.1. Rodvækst............................................................................................................ 22

    4.1.2. Skudvækst .......................................................................................................... 23

    4.2. Lugtløs Kamille ......................................................................................................... 24

    3.1.2. Rodvækst............................................................................................................ 25

    3.1.3. Skudvækst .......................................................................................................... 25

    5. Diskussion ........................................................................................................................ 26

    5.1. Hypotese 1 ................................................................................................................. 26

    5.1.1. Rodvækst................................................................................................................ 26

    5.1.2. Skudvækst .......................................................................................................... 27

    5.2. Hypotese 2 ................................................................................................................. 27

    5.2.1. Agerrævehale ..................................................................................................... 28

    5.2.2. Lugtløs Kamille ................