Springer Online Journal Archives 1860-2000
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Summary Reciprocal grafts of aphid-resistant (Rastatter) and susceptible (Schlanstedter) field beans (Vicia faba) should demonstrate whether the resistance of the scions is influenced by the stock or not. To ensure a solid and inflexible connection between the partners to be grafted a glass capillary was fitted in the stem hollows of both the scion and the stock. In “pertelar” cages (Müller 1954) one young aptera of Aphis fabae could choose to infest a leaf of a grafted scion or a leaf of a normal plant. The percentage of initial colonies established by 740 such tested virginoparae decreased from 90,6 (S/R+S) to 78,5 (S/R+R), 76,7 (R/S+S) and 48,8% (R/S+R). In all cases, where a decision was possible at all, S-leafs were preferred to R-leafs, independently of whether they grew on a scion or on a normal plant (Table I): With reproduction rate experiments the percent of apterous virginoparae settling on grafts and controls dropped in a similar manner from 51,0 on S and 43,9 on S/R to 21,8 on R and 17,7 on R/S respectively (Table II). Also the reproductive rate (number of larvae born by an apterous virginopara in the time between the birth and maturity of its first born daughter decreased from S (33,6+-9,0) and S/R (31,8+-8,3) to R (27,2+-8,2) and R/S (26,7+-7,9)). There is no statistically significant difference between S and S/R on the one side and R and R/S on the other (Fig. 4). The diminution of numbers from S to S/R and from R to R/S respectively in all experiments is suggested to be an effect of grafting in itself rather than a mutual influence of the partners. The present results prove that both the preference-nonpreference-und the antibiosismechanism of the relative aphid resistance of R-and S-field beans are not altered by the stock after reciprocal grafting. In view of this and the findings of Harvey & Hackerott (1958) on alfalfa resistance against Therioapbis maculata substances produced by the roots cannot be the cause of aphid resistance.
Zusammenfassung Das Präferenz-Nonpräferenzverhalten sowie die antibiotisch beeinfluβte Höhe der Reproduktionsrate von Aphis fabae gegenüber Ackerbohnensorten (Vicia faba) änderten sich nicht, wenn eine resistente Sorte (Rastatter) auf eine anfällige (Schlanstedter) gepfropft wurde oder umgekehrt. Verhalten und Vermehrung der Blattläuse richteten sich stets nach dem Sortencharakter des Reises, unabhängig von dessen Unterlage.
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