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Samuel G. Obae, Mark H. Brand, and Richard C. Kaitany

objectives were to use AFLP markers to: 1) authenticate the trueness-to-name of B. thunbergii plants from different nurseries and control for mislabeled plants in the market; 2) evaluate the occurrence of genetic variants within cultivars; and 3) develop a

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Charles R. Brown

potato breeding was in private hands in 1850, that the Reverend Chauncey Goodrich undertook his calling to fight hunger on receiving potatoes from the Panamanian Consulate, which came with the name “Chili,” perhaps denoting the country of origin as Chile

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Paul Vossen

BOTANICAL CLASSIFICATION OF THE OLIVE The true genetic origin of today's cultivated olive Olea europaea L. var. communis is not known. Some scientists believe that the “European” olive, which has the only Olea with sufficiently large

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Claude E. Thomas, Amnon Levi, and Ellis Caniglia

Two hundred sixty-six Citrullus lanatus (Thumb.) Matsum. & Nakai accessions (Plant Introductions and named cultivars) were tested against a race 2 Sphaerotheca fuliginea (Schlechtend.: Fr.) Pollacci isolate to evaluate for resistance to powdery mildew disease. Growth room-grown seedlings were artificially inoculated with conidia from watermelon host leaves at 2-day intervals from the appearance of the first true leaf until test results data were taken, when the second true leaf was fully expanded. Plants were evaluated on a 1 to 9 scale of increasing disease severity. Disease indices (DIs) were calculated as weighted averages for each entry. All genotypes with resistant plants (powdery mildew rating 1 to 3) were reevaluated in a replicated test of 3 replications of 10 plants each. Disease indices were again calculated. Twenty-two plant introductions (PIs) and one named variety displayed intermediate resistance to powdery mildew in the replicated test with DIs ranging from 5.0 to 6.0.

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Edward J. Ryder

Three chlorophyll deficiency traits in lettuce (Lactuca sativa) are reported. One, chlorophyll deficient-3 (cd-3), is quite yellow in the seedling stage, and controlled by a single recessive allele. Chlorophyll deficient-4 (cd-4) has sectors of yellow-green and green in the true leaves. It is inherited as a single recessive, and may be allelic to chlorophyll deficient-2 (cd-2). Sickly (si) is stunted, yellow, and partially necrotic, and is also controlled by a single allele. Virescent (vi) is epistatic to cd-4 and the latter is partially lethal. Linkage and additional epistatic relations with previously named chlorophyll deficient genes and other traits are discussed.

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John R. Stommel and Stephen L. Sinden

The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.

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Douglas A. Cox

solely to indicate this fact.

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James P. Gilreath, Carlene A. Chase, and Salvadore J. Locascio

1 To whom requests for reprints should be addressed. E-mail address: Florida Agricultural Experiment Station Journal Series No. R-07747. The cost of publishing this paper was defrayed in part

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Mónica Moura, Maria Irene Candeias, and Luís Silva

endemic to the Azores islands. As a result of long-term human pressure over the native vegetation areas, several of these endemic taxa are currently rare or very rare ( Schäfer, 2003 ), and the development of conservation strategies for the endemic Azorean

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Yun-Chan Huh, Seung-Ryong Cheong, and Jung-Myung Lee*

Common watermelons have an indeterminate growth habit with normal internode length, thus allowing the vine to grow indefinitely under the normal conditions. Watermelon breeders have identified four dwarf genes (dw-1, dw-1 s , dw-2, dw-3) and used these for developing dwarf watermelon cultivars. We discovered a naturally occurring new dwarf and seedless mutant (NDSM) from a landrace cv. Mudungsan that had been cultivated in the Mountain Mudung area nearby Gwangju City in Korea. The progenies of this mutant segregated in a ratio of 3 vine to 1 dwarf indicating a single recessive gene nature. Morphological characteristics of the NDSM were markedly different from those of the four known dwarf genotypes. NDSM plants grow shorter than 1 m in length with fan-shaped leaves and have fewer leaf lobes than normal plants, which could be clearly distinguished at 2 or 3 true leaf stage. Male and female flowers have just one petal and failed to open completely even at the anthesis. Even though there were some fertile pollen grains, the fruits of NDSM had no seed after fertilization. The F2 progenies, obtained from crossing `920533' (normal vine type) and NDSM, segregated in a ratio of 3 vine to 1 dwarf. All F1 plants from crosses between 2 dwarf types, `Sugar Bush' (dw-1dw-1) and `NH 9' (dw-2dw-2), and NDSM were normal, while F2 showed 9 vines, 3 dw-1 or dw-2 types, 3 NDSM types, and 1 double dwarf. The backcross generation segregated in a ratio of 1 vine to 1 dwarf. These results indicate that the genes for the NDSM and 2 dwarf types are non-allelic. We named this new dwarf genotype (NDSM) as dw-4 in addition to four dwarf genes previously identified.