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Raymond J. Schnell and Robert J. Knight Jr.

Five isozyme systems were used to detect zygotic seedlings from five polyembryonic cultivars of mango (Manifera indica L.). Significant differences were found between cultivars (x2 = 35.53, P < 0.001) for the percentage of zygotic and nucellar seedlings detected. The range of variation in the percentage of off-types was from 0% in 13-1 to 64% in Golek. The percentage in Sabre was 4%, and 24% and 36% in Tupentine and Madoe, respectively. Three of eight rootstock mother trees of Turpentine were determined to be off-types.

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Michael K. Hennessey, Robert J. Knight Jr., and Raymond J. Schnell

Seventeen avocado selections from the U.S. Dept. of Agriculture Miami National Clonal Germplasm Repository were bioassayed for antibiosis to Caribbean fruit fly eggs and larvae. Two colony-reared strains of flies were used. Fourteen of the selections did not support any development of immature stages to the adult stage. The results support the contention that highly resistant cultivars would not pose a high risk of spreading Caribbean fruit fly to foreign markets even without postharvest disinfestation treatment.

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Thomas M. Gradziel, Robert J. Knight Jr., William Reid, Chad E. Finn, John R. Clark, Eliezer S. Louzada, and Kim E. Hummer