Inheritance of partial resistance to Septoria tritici in wheat (Triticum aestivum): limitation of pycnidia and spore production
The aim of this work was to study the gene effects of two components of partial resistance (pycnidia.cm and spore production.mL-1) in a semi-diallel cross of four wheat cultivars differing in susceptibility to Septoria tritici. The F1 trials were carried out in two environments (greenhouse and field). The material was inoculated at the beginning of tillering (stage 21, Zadoks scale) and evaluations were performed on the fourth leaf. There was a significant interaction between crosses and environments for pycnidia.cm-.2 A separate ANOVA was performed for both traits. Crosses were significant for both traits in both environments. Griffing method 4, model 1 was used to test general and specific combining ability. General combining ability mean square was usually larger than the specific combining ability mean square. The presence of significant additive variance indicates the possibility of selecting for both traits in order to obtain partial resistant cultivars. However, it is necessary to consider that for pycnidia.cm the dominance variance was also large, indicating that selection for this trait should be delayed to advanced generations. The environmental influence is discussed.