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Paul W. Foote, J. Scott Cameron, Chuhe Chen, and Stephen F. Klauer

Gas exchange rates were measured in the field on middle leaflets of Fragaria chiloensis (L.) trifoliates which were then used for Rubisco quantity and activity assays. Side leaflets of the same leaf were utilized for fourth-derivative spectroscopy, chlorophyll extraction, and specific leaf weight data. Differences of CO2 assimilation (A) rates were highly significant between genotypes ranging from 16.2 to 27.6 μmol CO2·s·m. Chlorophyll a and b, and total chlorophyll per unit area were positively correlated to A (r = 0.48**, 0.45**, and 0.49**, respectively). Total chlorophyll per unit dry weight had a correlation coefficient with A of 0.6**.

Fourth-derivative analysis of in vivo leaf attenuance spectra showed a positive correlation between A and Ca693 peak amplitude and a negative correlation of A and Ca677 peak amplitude. Peak amplitude of Ca693 was also correlated with chlorophyll content.

Activity per unit Rubisco was not a significant factor influencing A, but Rubisco quantity on either a leaf area or a dry weight basis was positively linked to A (r = 0.40** and 0.44**, respectively).

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C.M. Ronning, S.P. Kowalski, L.L. Sanford, and J.R. Stommel

The Colorado potato beetle is a serious pest of the cultivated potato. Natural resistance has been found in a few wild species, including Solanum chacoense Bitter, in which resistance is attributed to the presence of foliar specific leptine glycoalkaloids. Production and accumulation of these compounds within S. chacoense varies widely and appears to be inherited in a quantitative fashion, but high leptine producing clones occur rarely. In the present study, 15 different accessions from various locations and altitudes of origination were analyzed for foliar glycoalkaloid content in order to determine the frequency and distribution of genes for leptine production/accumulation, and to see if we could find a center, or core, of leptine production. Leptines were detected in eight of the 15 accessions, and the amounts within each accession varied widely, but none of the individuals produced high amounts of leptine (defined as greater than 62% of total glycoalkaloids). All of the leptine-containing accessions originated from western Argentina. There was no relationship between elevational level and leptine, but there was a negative trend with total glycoalkaloids and elevation; this was due to levels of solanine and chaconine decreasing with increasing elevation. In addition, nine unidentified glycoalkaloids were detected, in very high proportions in some individuals and accessions. AFLP marker frequency and diversity were used to compare subpopulations of these accessions. AFLP markers revealed substantial diversity among clones. The relationship of marker distribution to glycoalkaloid content is discussed. The results raise interesting questions about glycoalkaloid biosynthesis and inheritance, and point the direction for new avenues of leptine and glycoalkaloid research.

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Taryn L. Bauerle, William L. Bauerle, Marc Goebel, and David M. Barnard

( Bilderback, 2002 ). However, containerized plants have a limited substrate volume, often times requiring several irrigation events per day. Moreover, variability in substrate moisture within a container can be substantial, making characterization of available

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Ed Etxeberria, Pedro Gonzalez, Ariel Singerman, and Timothy Ebert

., 2011 ) adds to the inconsistency and inexactitude of the results. To overcome the ambiguities in C Las titer determinations by using a different set of leaves for every test and to lower the numerical variability between samples, we developed a

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Babak Talebpour, Maksut Barış Eminoğlu, Uğur Yegül, and Ufuk Türker

necessary to map yields for each tree in an orchard and use these data to determine the cause of variability in the orchard, and also optimize input applications on a site-specific basis ( Brown and Rosenstock, 2006 ). Initial investigations have been

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Hrvoje Rukavina, Harrison Hughes, and Randy Johnson

environments. Environmental factors are commonly measured directly as climatic or indirectly as geographical variables ( St Clair et al., 2005 ). It is generally thought that adaptation to local environments has generated variability within grass species

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Uttara C. Samarakoon, Keith A. Funnell, David J. Woolley, and Edward R. Morgan

distribution detected more variability among cultivars than standard deviation, hence was used in most of the subsequent analyses. There was no significant difference in the 10th to 90th percentile distribution of time (days) from the emergence of the first

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Mobashwer Alam, Craig Hardner, Catherine Nock, Katie O’Connor, and Bruce Topp

differences in leaf, stem, and growth parameters were identified ( Table 1 ). Both cultivars showed variability in nut and kernel size ( Fig. 3 ). There was no significant differences for average nut and kernel weight, but significant differences were detected

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Zahra Noormohammadi, Mehdi Hosseini-Mazinani, Isabel Trujillo, Luis Rallo, Angjelina Belaj, and Majid Sadeghizadeh

. Allelic composition of studied olive accessions for thirteen microsatellite markers. High variability in average number of alleles per locus in olive cultivars has been also reported by other workers ( Belaj et al., 2004 ; Carriero et al., 2002

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Ossama Kodad, José M. Alonso, María T. Espiau, Gloria Estopañán, Teresa Juan, and Rafel Socias i Company

heterozygosity in this species ( Kester et al., 1990 ; Socias i Company and Felipe, 1992 ). This large variability has provided a useful genetic pool for almond evolution, allowing in each growing region the selection of almond cultivars well-adapted to this