Morphological variation in tomato: a comprehensive study of quantitative trait loci controlling fruit shape and development

Abstract

Variation in fruit morphology is a prevalent characteristic among cultivated tomato. The genetic and developmental mechanisms underlying similarities and differences in shape between the fruit of two elongated tomato varieties were investigated. Fruit from two F2 populations constructed from either Solanum lycopersicum cv. Howard German or cv. Banana Legs crossed with S. pimpinellifolium accession LA1589, and one BC1 population constructed with S. lycopersicum Howard German as the recurrent parent, were analysed for shape by using a new software program Tomato Analyzer. Quantitative trait loci (QTLs) controlling 15 individual shape attributes were mapped by both single and multitrait composite interval mapping in each population. In addition, principal components analysis and canonical discriminant analysis were conducted on these shape attributes to determine the greatest sources of variation among and between the populations. Individual principal components and canonical variates were subjected to QTL analysis to map regions of the genome influencing fruit shape in the cultivars. Common and unique regions, as well as previously known and novel QTLs, underlying fruit morphology in tomato were identified. Four major loci were found to control multiple fruit shape traits, principal components, and canonical variates in the populations. In addition, QTLs associated with the principal components better revealed regions of the genome that varied among populations than did the QTL associated with canonical variates. The QTL identified can be compared across additional populations of tomato and other fruit-bearing crop species.

Relationship between germination and bell pepper seed structure assessed by the X-ray test

“…One available option is the use of a Tomato Analyzer software developed for the semi-automatic evaluation of the phenotypic characteristics of fruits, which can be adapted to seed analysis. This software can substitute the determination of some morphological attributes measured manually or estimated subjectively (Brewer et al, 2006;Brewer et al, 2007), and allow a faster phenotypic analysis resulting in information with a high degree of consistency and repeatability. Preliminary studies in cotton (Gossypium hirsutum L.) and cucurbits seed testing has shown promising results.…”

Distribution ofSUN, OVATE, LC, andFASin the Tomato Germplasm and the Relationship to Fruit Shape Diversity

“…When adding the FAS mutation to the SUN-LC mutant background, the fruit is less elongated and, instead, oxheart in shape. Fruit shape in rectangular, ellipsoid, and heart-shaped varieties that do not carry the OVATE or SUN mutation might be controlled by genes such as those underlying the shape QTL fs8.1 and/or tri2.1/dblk2.1 controlling fruit elongation (Grandillo et al, 1996;Ku et al, 2000;Brewer et al, 2007;Gonzalo and van der Knaap, 2008). However, without the knowledge of the underlying genes at fs8.1 and tri2.1/dblk2.1 and the mutations that gave rise to the altered fruit shape phenotype, it is not possible to survey the alleles at these QTL throughout the germplasm.…”

“…Fruit shape and locule number are quantitatively inherited characters with estimates of quantitative trait loci (QTL) number ranging from four to 17 with the major loci explaining 19% to 79% of the genetic variation (Barrero and Tanksley, 2004;Brewer et al, 2007;Gonzalo and van der Knaap, 2008). The sun and ovate loci control fruit elongation and the underlying genes are known.…”

Use of image analysis techniques to determine the embryo size of Senna multijuga (Rich.) seeds and its relation to germination and vigor

“…However, aiming at a higher analysis precision, it is important to use specific softwares. The Tomato Analyzer ® (TA) software allows substituting evaluations of morphological attributes through manual or subjective estimation measures (Brewer et al, 2006;Brewer et al, 2007;Brewer et al, 2008). The system makes quantitative evaluations in an objective and semi-automatic way, accelerating the phenotypic analysis and obtaining highly consistent and repeatable information.…”