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Gansu Agricultural University (2021)

Defense Mechanisms of Different Drought-tolerant Potato Cultivars against Green Peach Aphids under Drought Stress

PETER QUANDAHOR

Titre : Defense Mechanisms of Different Drought-tolerant Potato Cultivars against Green Peach Aphids under Drought Stress

Auteur : PETER QUANDAHOR

Grade : Doctoral Dissertation 2021

Université : Gansu Agricultural University

Résumé partiel
Availability of water is critical for plant growth and their resistance to insect pests,and thus understanding plant responses to simultaneous stressors,such as drought and insect pests,is necessary.Potato(Solanum tuberosum L.)is a vegetable crop that plays a major role in global food security.However,its production and sustainability is adversely affected due to aphid infestation.Other researchers reported that drought severity could result in the outbreak of insect pests such as aphids.Therefore,the identification of drought-tolerant cultivars as well as cultivars that possess some resistance to insect pests has become an important area of research.The first experiment was conducted to determine the effect of drought and aphid(Myzus persicae Sulzer)infestation on three potato(Solanum tuberosum L)cultivars under greenhouse conditions.In the second experiment,the root system architecture and biochemical responses of three potato(Solanum tuberosum L.)cultivars to drought and aphid(Myzus persicae Sulzer)infestation under greenhouse conditions was conducted.In the third experiment,the cross-talk of phytohormones in potato glycoalcaloids defense against green peach aphids under greenhouse conditions was examined.In the fourth experiment,the effect of three concentrations of the leaf extract(100,75,and 50% potato extract),synthetic pesticide and distilled water(control)treatments on green peach aphids was assessed.All the four experiments were conducted under greenhouse condition.The results of the first experiment show aphid survival rate on plants under no drought(87.7%)and those under drought(67.2%)were highest on QS9 and least on DXY(41.3% and31.2%,respectively).Colonization success of aphids on plants under no drought and on those exposed to drought was highest on QS9(24.2 and 19.5%,respectively)and least on DXY plants(13.7 and 10.9%,respectively).The drought-sensitive cultivar,DXY,exhibited greater tolerance to peach aphid under drought or no drought conditions.This was demonstrated by poor aphid performance and higher biomass accumulation of this cultivar.However,the drought-tolerant cultivar,QS9,was highly susceptible to the peach aphid.This was shown by the high aphid performance and low biomass accumulation.Furthermore,the extreme water loss of the sensitive cultivar,DXY,dramatically decreased the performance of the green peach aphid under drought stress.The drought-tolerant cultivar exhibited high water content on which the green peach aphid is able to absorb from the xylem sap,thereby improving the performance of the green peach aphid.Resistance of the DXY cultivar to peach aphid may also be due to the presence of toxic compounds in the plants,since it exhibited poor host acceptance.Thus,the DXY cultivar can be considered to increase potato yield in areas where peach aphids are a major constraint.This study demonstrates that the biochemical and morphological traits that confer drought tolerance in potato do not necessarily confer aphid tolerance.

Mots clés : potato ;drought stress ;aphid infestation ;secondary metabolite ;root architecture ;detoxifying enzymes ;

Présentation (CNKI)

Page publiée le 20 octobre 2021