Field Crops Research 149 (2013) 203–212 Contents lists available at SciVerse ScienceDirect Field Crops Research jou rn al hom epage: www.elsevier.com/locate/fcr Phenotypical diversity of winter triticale genotypes collected in the Polish gene bank between 1982 and 2008 with regard to major quantitative traits Joanna Ukalska a,∗ , Wanda Kociuba b a Biometry Division, Department of Econometrics and Statistics, Faculty of Applied Informatics and Mathematics, Warsaw University of Life Sciences, Nowoursynowska 159 Street, 02-776 Warsaw, Poland b Institute of Plant Genetics, Breeding and Biotechnology, University of Life Sciences in Lublin, Akademicka 15 Street, 20-950 Lublin, Poland a r t i c l e i n f o Article history: Received 15 October 2012 Received in revised form 9 May 2013 Accepted 11 May 2013 Keywords: Best linear unbiased predictor Germplasm Principal component analysis Winter triticale (×Triticosecale Wittmack) Phenotypic diversity Yield components a b s t r a c t Genetic resource collections of crop plants constitute a source of knowledge about the biodiversity of a given species. Understanding the variability of the large number of genotypes in a collection gathered over the years can facilitate the selection of desired traits for breeding and research. The aim of this study was to analyze the variability of genotypes of winter triticale (×Triticosecale Wittmack) based on 11 phenotypic traits (morphological and phenological, yield components and grain protein content) and to determine the most differentiating features of a collection gathered in the years 1982–2008. The experimental material consisted of 1006 hexaploid triticale genotypes differing in geographical origin. A random two-way genotype × year model was applied, where mean genotypic values were esti- mated using the BLUP estimators. Principal component analysis (PCA) was performed on the correlation matrix of the studied traits. The greatest diversity of genotypes related to yield components (grain weight per spike, number of grains per spike and spikelet fertility). In the 1980s the genotypic means of these traits were lower than the multi-year means. In subsequent years, decreasing differentiation of these traits was observed with the simultaneous increase of their genotypic mean values. Mean protein con- tent was the highest (>15%) in the 1980s, and since the beginning of 2000 it has remained below 11%. By the mid-1990s, the genotypic means for plant height and spike length were greater than the multi-year means (118 cm and 10.2 cm, respectively) and these features were highly differentiated. However, since the late 1990s, the mean values of these features have not exceeded 115 and 10 cm, respectively. The first three principal components, PC1, PC2 and PC3, explained a total of 63–80% of the overall variation between the examined objects. The number of grains per spike, grain weight per spike, spikelet fertility and the number of spikelets per spike were most strongly correlated with PC1. Also, these traits were the ones which mostly differentiated the population of triticale genotypes throughout the studied years. By the mid-1990s, plant height was most closely correlated with PC2, and spike length in subsequent years. The traits, which were most strongly correlated with PC3, were 1000-grain weight, and in the 1980s the number of days from emergence to earing. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Triticale (×Triticosecale Wittmack) is a man-made cereal formed by crossing wheat with rye. It possesses the genomes of the genus Triticum and Secale ssp., and thus the advantageous properties of wheat grain with the features of rye, such as resistance to abiotic and biotic stresses. Abbreviations: BLUP, best linear unbiased predictor; CV, coefficient of variation; PCA, principal component analysis. ∗ Corresponding author. Tel.: +48 225937262; fax: +48 225937211. E-mail address: joanna ukalska@sggw.pl (J. Ukalska). According to the data from FAO (FAOSTAT, 2011), in the years 1982 through 2008 triticale was grown in 37 countries worldwide. The adopted triticale cultivars have high grain yield potential. How- ever, fertility still remains an issue and is a topic high interest in breeding research. Breeders are also interested in finding sta- ble genotypes with broad adaptation possibilities, especially those concerning yield and its quality (Goyal et al., 2011). According to Lukaszewski and Apolinarska (1981) and Zillinsky (1980), the supe- rior hybrids are the ones which have a full rye genome, which has an impact on their extensive adaptation to changing climate and cultivation conditions. In Poland, the first triticale cultivars were registered by the Research Centre for Cultivar Testing in Poland (COBORU) in 1982. 0378-4290/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fcr.2013.05.010