Most temperate fruit tree breeding programs pay major attention to fruit quality, chilling requirement, crop load, and tolerance to disease. In contrast, limited effort has been devoted to tree architecture and tree branching patterns (Berthelemy and Caraglio, 2007). As labor and pruning costs of fruit trees have increased, size control and tree architecture in fruit trees have gained importance. Tools for the evaluation and early selection of architectural traits expressed late in development would represent a major advancement for fruit tree breeders (Laurens et al., 2000). Factors such as tree vigor and sylleptic (immediate) and proleptic (delayed) branching have major effects on the presence of a large number of thin branches or “twigginess” of stone fruit trees.
Various types of plant growth models that integrate plant topology and plant geometry to study plant architecture are available (Fourcaud et al., 2008). Another means to portray plant architecture is the development of indices (Godin et al., 1999). An index based on the plastochron development of Glecoma hederacea L. was used to analyze stolon growth and branching (Birch and Hutchings, 1992). An index based on length and density or number of first-order and second-order roots was used to describe the degree of branching in maize roots (Morita et al., 1992). Analysis of lateral branching has been used to study architectural traits. In apple, lateral branching has high heritability and is correlated with topological traits (Segura et al., 2006).
Tworkoski and Scorza (2001) indicate that although there are numerous growth forms in peach, little effort has been made to describe and control tree architecture. They stated that compact peach trees have increased branching in roots and limbs. The aim of this research was to develop a simple and reliable branching index that could be used to evaluate the architecture of peach seedlings, thus facilitating the early selection of individuals with desirable tree architecture. The developed index uses first-order branch data and higher-order branch data from three first-order branches as the basis to characterize seedling trees.
Berthelemy, D. & Caraglio, Y. 2007 Plant architecture: A dynamic, multilevel and comprehensive approach to plant form, structure and ontogeny Ann. Bot. (Lond.) 99 375 407
Birch, C. & Hutchings, M.J. 1992 Stolon growth and branching in Glechoma hederacea L.: An application of a plastochron index New Phytol. 122 545 551
Fourcaud, T., Zhang, X., Stokes, A., Lambers, H. & Örner, C.K. 2008 Plant growth modeling and applications: The increasing importance of plant architecture in growth models Ann. Bot. (Lond.) 101 1053 1063
Genard, M., Pages, L. & Kervella, J. 1994 Relationship between sylleptic branching and components of parent shoot developments in the peach tree Ann. Bot. (Lond.) 74 465 470
Godin, C., Costes, E. & Sinoquet, H. 1999 A method for describing plant architecture which integrates topology and geometry Ann. Bot. (Lond.) 84 343 357
Gradziel, T.M., Kester, D.E. & Martinez-Gomez, P. 2002 A development based classification for branch architecture in almond J. Amer. Pom. Soc. 56 106 122
Laurens, F., Audergon, J.M., Claviere, J., Duval, J., Germain, H., Kervella, J., Le Lezec, M., Lauri, P.E. & Lespinasse, J.M. 2000 Integration of architectural types in French programmes of ligneous fruits species genetic improvement Fruits 55 141 152
Legave, J.M., Segura, V., Fournier, D. & Costes, E. 2006 The effect of genotype, location and their interaction on early growth and branching in apricot trees J. Hort. Sci. Biotechnol. 81 189 198
Morita, S., Thongpae, S., Abe, J., Nakamoto, T. & Yamazaki, K. 1992 Root branching in maize. Branching index and methods for measuring root length Jpn. J. Crop. Sci. 61 101 106
Segura, V., Cilas, C., Laurens, F. & Costes, E. 2006 Phenotyping progenies for complex architectural traits: A strategy for 1-year-old apple trees (Malus × domestica Borkh.) Tree Genet. Genomes 2 140 151
Tworkoski, T. & Scorza, R. 2001 Root and shoot characteristics of peach trees with different growth habits J. Amer. Soc. Hort. Sci. 126 785 790