Wooster, Ohio
May 4, 2009
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Improved software measures fruit shapes and eccentricity
Photo by Esther van der Knaap |
Tomatoes come in a variety of
sizes and shapes, making them the perfect subject to test
shape-analyzing software. The Tomato Analyzer is "rapidly
becoming the standard for fruit morphological
characterizations," according to a study led by Marin Talbot
Brewer of The Ohio State University's Department of Horticulture
and Crop Science. Details of the team's latest Tomato Analyzer
research were published in a recent issue of the Journal of the
American Society for Horticultural Science.
Morphology studies the form and structure of organisms. Software
such as the Tomato Analyzer aids in morphological research by
providing accurate and objective measurements of fruit shape.
The analysis is also more efficient for large numbers of
subjects and can detect traits that are extremely difficult to
quantify manually. The Tomato Analyzer uses mathematical
descriptors to quantify various shape features based on the
boundary of the fruit.
Morphometrics studies the quantitative analysis of the shape and
size of a biological form using the position of and distance
between landmarks. This method has been used to study
variations, classifications, and evolutionary analyses, as well
as genetic studies of animals and insects. Morphometric analysis
is less biased and depends less on manual manipulation, but the
results are abstract quantities. The Tomato Analyzer's results
are more descriptive because they actually measure angles or
include ratios that better explain the fruit shape. However, the
Tomato Analyzer provides both methods in the same application,
allowing the researcher to select the option that best suits the
project's needs.
A main objective of the study was to investigate the
quantitative trait loci (QTL), which are parts of the genetic
code that control fruit shape. The QTL as determined by
morphometric analysis and boundary analysis were then compared.
A new set of measurements was added to the Tomato Analyzer
software to calculate the area of the pericarp, septum, and
placenta. These are internal segments of the fruit that help to
explain the shape more thoroughly than the exterior silhouette
alone.
In the 'Sausage' species of tomato, two loci were identified as
controlling more than 50% of the internal shape index, which
gives the tomato its elongated or "pear" shape. Visual
observation supported that the software accurately measured the
degree of pear shape. Additional tests to determine proximal end
angle, the shape of the fruit nearest the stem, showed
comparable results between the two methods. This adds to the
software's versatility of measurements for researchers.
QTLs detected in 'Sausage' and 'Rio Grande' varieties of tomato
overlapped significantly. Though most, if not all, of the QTL
controlling fruit shape and size were identified using the
Tomato Analyzer applications, morphometric analyses are an
efficient way to investigate the various sizes and shapes of
fruit. Because both types of analysis are available in the
Tomato Analyzer, the software allows researchers to quickly note
morphological variation with the morphometrics function and then
delve more deeply into the details using the attribute function.
The complete study and abstract are available on the ASHS
Journal of the American Society for Horticultural Science
electronic journal web site:
http://journal.ashspublications.org/cgi/content/abstract/134/1/77
Original Article
Tomato Fruit Shape
Analysis Using Morphometric and Morphology Attributes
Implemented in Tomato Analyzer Software Program
Maria Jose Gonzalo
Department of Horticulture and Crop Science, The Ohio
State University, Wooster, OH 44691 and Dept. de Pomología,
Estación Experimental de Aula Dei-CSIC, Apdo. 13034, 50080
Zaragoza, Spain
Marin Talbot Brewer, Claire Anderson and David Sullivan
Department of Horticulture and Crop Science, The Ohio
State University, Wooster, OH 44691
Simon Gray
Department of Mathematics and Computer Science, The
College of Wooster, Wooster, OH 44691
Esther van der Knaap
Department of Horticulture and Crop Science, The Ohio
State University, Wooster, OH 44691
J. Amer. Soc. Hort.
Sci. 2009 134:77-87. [Abstract]
[Full
Text] [PDF]
ABSTRACT
Reliable analysis of plant traits depends on the accuracy of
scoring the phenotype. We report here on the efficacy of two
methods in the detection of quantitative trait loci (QTL)
controlling fruit morphology in three segregating tomato
(Solanum spp.) F2 populations using the software program,
Tomato Analyzer. The first method uses fruit morphology
attributes such as fruit shape index, blockiness, pear
shape, indentation area, and angles of the fruit along the
boundary. The second method uses morphometric points to
quantify shape. The morphometric data were subjected to
principle components analysis (PCA). QTL that control the
fruit morphology attributes and the morphometric PCA were
identified that revealed that the methods were comparable in
that they resulted in nearly identical loci. Novel
attributes were added to Tomato Analyzer that improved
versatility of the program in measuring additional
morphological features of fruit. We demonstrated that these
novel attributes permitted identification of QTL controlling
the traits.
Founded in 1903, the
American Society for Horticultural Science (ASHS) is the largest
organization dedicated to advancing all facets of horticultural
research, education, and application. More information at
www.ashs.org |
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