Genotypic variability of root and shoot traits of bread wheat (Triticum aestivum L.) at seedling stage

The evaluation of the embryonic root and stem of bread wheat (Triticum aestivum L.) in the early stage of development (seedling stage) can be a powerful tool in wheat breeding aimed at obtaining progenies with a greater early vigour. It is revealed that genotypes with faster early vigour have produced higher biomass and grain yield. In this study, the evaluation of traits of the embryonic root and the embryonic stem of 101 bread wheat genotypes was preformed at the 10-day old seedlings. The following eight morphological traits of roots and stems were analysed: primary root length, branching interval, the number of roots, total length of lateral roots, angle of seminal roots, stem length, root dry weight and the stem dry weight. Analysed lateral roots included seminal roots. The greatest, i.e. the smallest variability of observed traits was detected in the branching interval, i.e. the stem length, respectively. The highest positive correlation was determined between the primary root length and the total length of lateral roots. The cluster analysis, based on observed traits, shows that genotypes were clearly divided into two main clusters, A and B. The two clusters essentially differed from each other in the values of the following traits: primary root length, total length of lateral roots, root dry weight, stem dry weight and the stem length. Genotypes with shorter primary and lateral roots, lower root and stem dry weight and a shorter stem were grouped in the cluster B. On the other hand, the cluster A encompassed genotypes with values of these traits above or around the average. The values of the remaining analysed traits: the angle of seminal roots, the number of lateral roots and the branching interval varied greatly between obtained clusters. The cluster analysis showed the homogeneity of genotypes originating from Serbia and the region; their values of the root and stem length and weight were mostly around and below the average. However, the values of the angle of seminal roots, number of lateral roots and the branching interval were above average.