Phenotypical diversity of winter triticale genotypes collected in the Polish gene bank between 1982 and 2008 with regard to major quantitative traits

Abstract

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 estimated 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 content 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 (118cm and 10.2cm, respectively) and these features were highly differentiated. However, since the late 1990s, the mean values of these features have not exceeded 115 and 10cm, 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.