| Broomrape?Orobanche spp.and Phelipanche spp.?as root parasitic weeds,which have caused severe damage to agriculture in many areas of the world.Because of special life cycle and numbers of seeds that can keep alive in soil for many years,conventional measure of control broomrape is hard to achieve effectively results.Trap crops can release a mixture to induce the germination broomrape seeds,but won't be parasitized.Gibberellin is able to break the secondary dormancy of the broomrape seeds and improve the sensitivity of the seed to the germination stimulants,increase germination of broomrape seeds.Promote the broomrape seeds bank in soil to the stimulants positive response by gibberellin,in order to reach the trap effect efficient,which has potienal value of reserch and application.Screen out the efficient trap crop variety by plug tray experiment and petridish experiment,then make sure the suitable concentration of gibberellin by stimulating germination of broomrape seeds by root exudate of trap crop,,further determin the suitable time of appling gibberellin by pot experiment.Verificate subduction of broomrape seeds bank by crop rotation experiment.The main conclusion of this study are as follows:?1?The ability of trap crop maize induce broomrape among variety have significant differences.The undiluted and 10-diluted methanolic extracts of root exudate of maize‘Xinyu No.57'plant in plug tray stimulate germination of sunflower broomrape seeds above60%.100-diluted methanolic extracts of root exudate of maize‘Xinyu No.57'stimulate germination rate of sunflower broomrape seeds higher than‘Jingnuo No.1'.So‘Xinyu No.57'was choosed as maize variety in pot experiment.Gibberllin increased the ability of maize induce sunflowe broomrape significantly.Germination of sunflower broomrape seeds were stimulate by 100-diluted methanolic extracts of maize aboveground which applied gibberellin at 10-44 mol·L-1 in pot increased significantly,germination of sunflower broomrape seeds have increased 39.4%and 31.7%compared with control respectively which applied gibberellin at the 20 days?D20?and the 40 days?D40?after planting maize.Germination of sunflower broomrape seeds were higher than control significantly,stimulating by 100-diluted methanolic extracts of maize root.,germination of sunflower broomrape seeds have increased 46.5%and 43.9%compared with control respectively which applied gibberellin at D20 and D40 after planting maize.The time of applying gibberllin not influenced significantly the ability of mazie inducing sunflower broomrape seeds,there were no significant difference about germination of sunflower broomrape seeds which induced by the aboveground and root methanolic extracts of maize which applied gibberellin at D20 and D40 after planting maize.The epigaeous number of sunflower broomrape were significantly reduced.The epigaeous number of sunflower broomrapes were reduced in 2017 by applying gibberellin at D20 and D40 after planting maize in pot,with the reduction of 76.4%and67.3%,respectively.Besides the treatment D20's dry weight of sunflower broomrape root reduced siginificantly 77.8%compared with control.The treatment of D20 and D40epigaeous number of sunflower broomrapes were 0.8·pot-1,reduced significantly compared with control in 2018,the treatment of control were 5.8·pot-1.?2?Ability of maize induces egyptian broomrape seeds germination was significnatly influenced by the concentration of gibberllin.Egyptian broomrape seeds germination rates induced by root exudate of maize which applied gibberellin at different concentration in plug tray were different.‘Xinyu No.57'root exudate which applied 10-44 mol·L-1 gibberellin stimualte egyptian broomrape seeds germination were 19.6%,significant higher than other treatments,Gibberellin at 10-44 mol·L-11 was applied in pot experiment.Tomatoes were planted after applying gibberllin to maize,the attached total number of egyptian broomrape reduced significantly.The result of pot experiment in 2016 show that the attached number which applyed gibbeerllin at D20 after planting maize reduced by 67.3%compared with control,and attached number in 2017 which applyed gibbeerllin at D40 after planting maize reduced by44.7%compared with control.?3?Maize reduced significantly epigaeous number of egyptian broomrape.Epigaeous number of egyptian broomrape of'Shihong 45'were 7.5·pot-1 by rotating with maize,but epigaeous number of egyptian broomrape were 19.5·pot-1 which not rotated with maize,compared with two treatments,the epigaeous rate of egyptian broomrape seeds reduced61.5%.The epigaeous number of Egyptian broomrape reduced significantly by trap crop maize rotates with host crop tomatoes,and the variety of host trap influenced the epigaeous number of egyptian broomrape.The epigaeous number of egyptian broomrape of‘Jiafan0738'and‘Shihong 59'were 3.8·pot-1 and 5.3·pot-1 respective,the epigaeous number of egyptian broomrape decreased by 72.5%and 66.5%respectively compared with the treatment of planting maize merely. |
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