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International Journal of Agronomy
Volume 2010 (2010), Article ID 637928, 9 pages
Research Article

Similarity Patterns and Stability of Environmental Response in Sunflower Hybrids

1Section of Genetics and Breeding, Di.B.C.A., University of Bari, 70126 Bari, Italy
2Institute of Plant Genetics, CNR, 70126 Bari, Italy
3University Farm “A. Servadei”, University of Udine, 33100 Udine, Italy
4Società Italiana Sementi (S.I.S.), Bologna, 40068 San Lazzaro di Savena, Italy
5Cereal Research Centre, CRA, 71122 Foggia, Italy
6Department of Biology Biotechnology and Agro-Forestry, University of Basilicata, 85100 Potenza, Italy

Received 20 July 2010; Revised 12 October 2010; Accepted 13 October 2010

Academic Editor: Rodomiro Ortiz

Copyright © 2010 V. Alba et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The rationale for the following research was to analyse the response of sunflower hybrids to different sowing dates and to evaluate hybrid response to critical environmental conditions. The data used are from an experiment conducted in a location-year combination over a period of two years (2007–09) in southern Italy. Eleven hybrids were tested following a randomized complete block design with three replications at each location-year combination. Eight agronomic characters including seed oil content were recorded. Classification and ordination procedures were used to investigate hybrid performance in relation to three different sowing dates. Combined analysis of variance showed that hybrids, location-year combination, sowing date and their interactions were highly significant for all characters. Hybrid performances were classified by cluster analysis into groups that were differentiable in terms of means and stability. The first three components accounted for 74%, 82%, and 87% of the total variation for the first, second and third sowing date respectively. Plotting component one against component two along Euclidean axes should therefore provide a reasonable representation of the spatial arrangements of hybrid performances in the original multi-dimensional space. The applied statistical method gives full information on hybrid performances similarity.