不同生殖生长期大豆器官对斜纹夜蛾抗性分析

Resistance Analyses of Soybean Organs to Common Cutworm(Spodoptera litura)at Different Reproductive Stages

为探究不同生殖生长期大豆器官对斜纹夜蛾的抗性,本研究选用不同抗性大豆品种R2、R4和R6期叶片,R4和R6期荚皮及R6期籽粒强迫喂食3龄斜纹夜蛾幼虫,评价不同生殖生长期不同抗虫性大豆品种的器官对斜纹夜蛾幼虫抗生性的影响。结果表明,喂食R2期叶片,3个品种平均的幼虫取食量、虫增重及粪便量均显著高于R4和R6期,即R2期为叶片对斜纹夜蛾的易感期。喂食R4期荚皮,幼虫的取食量、虫增重及粪便量均显著高于R6期,从而认为R4期为荚皮对斜纹夜蛾的易感期。取食R4期叶片虫增重高于荚皮,但取食量和粪便量低于荚皮,特别粪便量达显著水平,说明叶片因利用率高而对幼虫抗生性低。取食量、虫增重和粪便量在R6期器官间均达到极显著水平,取食量和虫增重均表现为喂食籽粒>叶片>荚皮,且存在显著差异。R4和R6期的取食选择性试验也表明3种器官对斜纹夜蛾的抗生性为:荚皮>叶片>籽粒。R4期荚皮抗生性和叶片抗生性在品种间表现较为一致。R6期叶片抗生性在品种间差异明显,而荚皮和籽粒抗生性在品种间差异较小,荚皮的抗生性都偏高,籽粒抗生性相反都偏低。取食量、虫增重及粪便量3个指标相对一致,而虫增重具有易称量等优点,可作为抗虫鉴定的主要指标。

In order to explore the resistance of soybean organs of different reproductive stages to common cutworm(CCW,Spodoptera litura Fabricius),the leaves at R2,R4 and R6,the pods at R4 and R6,and the seeds at R6 of soybean varieties with different resistance were used to forcibly feed the third-instar larvae for evaluating their resistances against S.litura,mainly antibiosis,in the present study.At R2,the average consumed leave amount,body weight increase and larval excrement amount of three varieties were significantly higher than those at R4 and R6 stages,while at R4,the consumed pod amount,body weight increase and excrement amount of larvae were significantly higher than those at R6 stage,thus R2 and R4 were the sensitive stages of antibiosis to S.litura for leaf and pod,respectively.The body weight increase of larvae fed on leaves at the R4 was higher than that of the pods,while consumed amount and excrement amount was lower,especially excrement amount reached a significant level,which means the antibiosis of leaves was lower than that of pods.The consumed amount,body weight increase and excrement amount of larvae reached significant level among the organs at R6 stage,in which the consumed seeds and body weight increase of larvae was significantly higher,followed by the amount of leaves,and pods were least.Thus,the antibiosis of soybean pod was higher,while that of the seed was lower.The feeding preference of different soybean organs at R4 and R6 stages showed pod<leaf<seed or the antixenosis against S.litura being:pod>leaf>seed.The antibiosis of pod and leaf against S.litura at R4 stage were relatively consistent among varieties but the antibiosis of leaf against S.litura at the R6 stage was significantly different among varieties,while the antibiosis difference of pod and seed against S.litura among varieties were relatively less.The consumed amount,body weight increase and excrement amount of larvae were relatively consistent,while body weight increase of larvae had the advantages for easy evaluation,and was recommended as the major indicator of CCW resistance evaluation.