| The experiment was conducted in Gangu Experimental and DaChaigou Township of Tianzhu County, from March to October in 2010. Thirty seven oat germplasm were inoculated by BYDV, their resistences were evaluated and the effect of inoculation on oat fresh yield, grain yield and components were studied. Field investigation and comprehensive evaluation were conducted in Tianzhu to test 15 oat varieties for their BYDV resistance. Two different seed coatings were used to treat covered and naked oat at different ratios, their effects on number of aphid, grain yield and yield components were studied.The main result are as follows:(1)From 37 oat germplasm, 3 high BYDV resistant were selected as Baiyan No. 2, Baiyan No.10, MF9715, taking up 8.1% of all materials. Meterials with medium-resistance were 409, QO245-7, NZ35, AC-7, taking up 10.8%. Meterials with medium-sensitive were 118,Blackbutt,Rigdon,AC-6,Sylva, accounting for 13.5%. The left were high-sensitive materials, accounting for 67.6%, among which, VAO-23, Keyan No.1, Jinyan No. 9, Chudao were the poorest.(2) Inoculation affected oat tillering severely, disease index was negatively correlated to number of tillers(r=-0.591). But MF9715, Baiyan No. 2, Baiyan No.10 were disease resistance with no significant difference was observed between treatement and control.(3) BYDV inoculation significantly inhibited plant height. The dwarf rate 99AS307, 440, Keyan No.1, Chudao, Dingyou No.4 were 30.9%, 30.2%, 34.1%, 27.7% and 21.8%, respectively. Baiyan No.10, Baiyan No.2, MF9715 had no significant difference compared with the control on durf rate.(4) BYDV inoculation significantly affected oat fresh yield. Disease index was negatively related to fresh yield(R=-0.326). BYDV caused red and harden leaves which restricted photosynthesis, meanwhile, tillering was also reduced, all these lead to great reduction in fresh yield. But different variety had didderent performance, MF9715, QO245-7, NZ35, Baiyan No.10, Baiyan No. 2 had no significant difference in fresh yield compared with the control; others were significantly decreased.(5) Oat grain yield decreased with the increasing BYDV disease index(r=-0.583). BYDV affected grain yield by panicle length, spikelet number, grains per panicle, 1000 grain weight and shrunken grains. Among 37 mayterials, MF9715, Baiyan No.2, Baiyan No.10 did not reduced their grain yield, while Keyan No.1, Jinyan No.9 and Chudao decreased their grain yield by 46.2%, 60.0% and 50.0%, respectively.(6)According to field investigation, QO245-7, Baiyan No.10, Baiyan No.2, MF9715 had little disease index, and belong to the resistant varieties, this was in accordance with inoculation result. 444, Sweet oat, Dingyou No.4 and other 10 varieties were mid-sensitive.(7) Although BYDV in the field was not severe as inoculation, it still affected grain yield and components. Disease index was positively correlated to number of shrunken grains(r=0.693), and negatively correlated to tillers(r=-0.653) and fresh yield (r=--0.563).(8) The integrated evaluation of oat resistance to BYDV reveald that the resistence order of covered oat wass 118>709>409>473>440>343>444>Tian>424. for naked oat,it was Baiyan No.2> Baiyan No.10> QO245-7> Bayou No.3> MF9715> Dingyou No.4.(9)300ml/50kg imidacloprid was the best treatment for covered oat, the least concentration (100ml/50kg )was enough for naked oat.(10) For thiamethoxam, the lowest concentration (100ml/50kg) was the best.(11) I/I* was positively correlated to number of shriveled grains.(12) I/I*was negatively correlated to plant height and grain yield. The severer the aphids, the severer BYDV, plant was shortened, photosynthesis was inhibited and grain yield was reduced. |
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