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Philip M. Sheridan and Richard R. Mills

Sarracenia L. is a genus of insectivorous plants confined to wetlands of the United States and Canada. Green mutants, lacking red pigmentation in the leaves, flowers, and growing point, have been found in most Sarracenia species. Controlled crosses were made using green mutants from S. rubra Walter ssp. gulfensis Schnell, S. purpurea L., S. psittacina Mich., and S. leucophylla Raf. Self-pollination of mutant green individuals in four different species resulted in green offspring, whereas reciprocal crosses with respective wild-types resulted in red offspring. Three of six self-pollinated heterozygous S. rubra ssp. gulfensis yielded offspring exhibiting a 3 red : 1 green ratio. Progeny from a testcross and two self-pollinated heterozygous plants of S. purpurea fit the expected ratios, whereas offspring from two S. purpurea crosses had significant deviations in field and laboratory sowing experiments. Offspring from testcrosses with S. rubra Walter ssp. jonesii (Wherry) Wherry met expected ratios under field conditions. Interspecific crosses between green individuals resulted in green offspring. These results suggest that anthocyanin pigmentation is controlled by two alleles at a single locus, with red dominant to green.

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Tim Holtsford and Jim Hancock

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Edward J. Ryder

Two new lettuce (Luctuca sativa L.) genes are described and named truncated leaf (tn), and sickly (si). A gene for reflexed involucre is identical to that previously described in wild lettuce (L. serriola L.). Mosaic reaction (me) and light green (lg) are linked, with P = 0.448. Six gene pairs tested for linkage are independently inherited. Sickly is epistatic to light green.

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Chih-Cheng T. Chao, Dan E. Parfitt, and Themis J. Michailides

. Bonin for similar services at Woflskill Experimental Orchard. This research used materials generated as part of a pistachio genetics and improvement program with cooperators D.E. Parfitt, C.T. Chao, L. Ferguson, C. Kallsen, and J. Maranto. The cost of

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Ryan J. Hayes, German Sandoya, Beiquan Mou, Ivan Simko, and Krishna V. Subbarao

.R. Michelmore, R.W. 1988 The genetics of corky root resistance in lettuce Phytopathology 78 1145 1150 Gurung, S. Short, D.P.G. Atallah, Z.K. Subbarao, K.V. 2014 Clonal expansion of Verticillium dahliae in lettuce Phytopathology 104 641 649 Hayes, R.J. Vallad

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Ryan J. Hayes, Carlos H. Galeano, Yaguang Luo, Rudie Antonise, and Ivan Simko

extended shelf life that reduce postharvest losses could increase production efficiency by reducing the frequency of product replacement in the marketplace. This is often difficult to achieve because there are few reports on the genetics of postharvest

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Xiaohe Song and Zhanao Deng

. Ochoa, O.E. Truco, M.J. Vick, B.A. 2005 Application of TRAP technique to lettuce ( Lactuca sativa L.) genotyping Euphytica 144 225 235 Jørgensen, J.H. 1994 Genetics of powdery mildew resistance in barley Crit. Rev. Plant Sci. 13 97 119 Kloos, W

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Richard Craig, Richard A. Grazzini, and R.O. Mumma

Resistance to mites and small insects in geranium results from the production of a viscous exudate on tall glandular trichomes present on the plant surface. This exudate exhibits sticky-trap properties immobilizing pests and reducing feeding and fecundity. The exudate is composed of long-chain 6-alkyl salicylic acids known as anacardic acids. The exudate of resistant plants contains 86% unsaturated anacardic acids. Susceptible genotypes possess fewer tall glandular trichomes and a trichome exudate which is dry and ineffective in trapping pests. The exudate from susceptible plants contains 70% saturated anacardic acids, thus explaining the physical state of the exudate. A single dominant locus controls the production of predominantly unsaturated versus saturated anacardic acids and thus resistance versus susceptibility. Other loci condition the ratio of C22:C24 unsaturated anacardic acids and the density of tall glandular trichomes. Current research involves the elucidation of the enzymatic pathway(s) involved in anacardic acid biosynthesis, identification of the regulatory enzymes and isolation of the mRNA transcripts associated with pertinent genes.

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Jack E. Staub and Karl Braunschweig

A teaching module was developed for computer-aided instruction of mutation theory. The Hypercard-driven, Macintosh compatible module illustrates the concepts of: 1) Changes in allele frequency with mutation pressure; 2) Number of alleles maintained in populations, and; 3) The Neutrality Hypothesis. The concepts are integrated in an application by using a game format.

Mutation is the ultimate source of genetic variation. Mutation pressure results in changes in allele frequency. Concept 1 illustrates the theoretical changes in allele frequency under pressure of reversible mutation. Mutation equilibrium is depicted as P=V/u+v; where v=mutation rates of allele A and u of allele a. The Infinite-Alleles Model of mutation is illustrated in Concept 2 and specifies characteristics of new mutations by F=1/4Nu+1, where F=fixation index and N=number in population. Concept 3 demonstrates the hypothesis that polymorphisms result from selectively neutral alleles maintained in a balance between mutation and random genetic drift.

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Jack E. Staub and Karl Braunschweig

A teaching module was developed for computer-aided instruction of mutation theory. The Hypercard-driven, Macintosh compatible module illustrates the concepts of: 1) Changes in allele frequency with mutation pressure; 2) Number of alleles maintained in populations, and; 3) The Neutrality Hypothesis. The concepts are integrated in an application by using a game format.

Mutation is the ultimate source of genetic variation. Mutation pressure results in changes in allele frequency. Concept 1 illustrates the theoretical changes in allele frequency under pressure of reversible mutation. Mutation equilibrium is depicted as P=V/u+v; where v=mutation rates of allele A and u of allele a. The Infinite-Alleles Model of mutation is illustrated in Concept 2 and specifies characteristics of new mutations by F=1/4Nu+1, where F=fixation index and N=number in population. Concept 3 demonstrates the hypothesis that polymorphisms result from selectively neutral alleles maintained in a balance between mutation and random genetic drift.