Phenotypic and molecular diversity of wheat species (Triticum spp.) in relation to plant height and heading time

Abstract

Plant height and heading time are important agronomic traits that significantly contributed to the improvement of wheat adaptability and yield. The aim of this study was to analyse genetic diversity of a collection of wheat species, originating from 20 countries, based on the microsatellite loci associated with the previously mapped quantitative trait loci of plant height and heading time, to estimate potential of microsatellites to detect polymorphism in different wheat species and reveal allelic patterns in relation to the geographical origin and to evaluate the level of phenotypic diversity. The principal coordinate analysis distinguished wheat genotypes by their origin and ploidy level. Wheat varieties from America, South and Southeast Europe, and West and Central Europe had the highest molecular diversity, as was evidenced by higher number of alleles, number of group-specific alleles, Shannon's information index and gene diversity. The Nei’s genetic identity indicated genetic similarity of geographically distinct groups, such as South and Southeast Europe and Russian (0.901) and South and Southeast Europe and American genotypes (0.638). The significant differences in plant height and heading time among different wheat groups were observed, while the differences in means among three different growing seasons and the group by season interactions were significant only for heading time. The evaluated collection with high observed level of both molecular and phenotypic diversity for plant height and heading time may be a valuable source of variation for wheat breeders to fine adjust these traits in order to achieve better agronomic performance in certain local environments.

Visina i vreme klasanja su važne agromonske osobine koje značajno doprinose poboljšanju sposobnosti pšenice da se prilagodi na uslove spoljašnje sredine i povećanju prinosa. Cilj ovog rada je da se oceni nivo fenotipske varijabilnosti ove dve osobine u kolekciji pšenica koje potiču iz 20 zemalja sveta, da se oceni njen molekularni diverzitet pomoću mikrosatelitskih markera povezanih sa prethodno mapiranim lokusima za kvantitativne osobine, i da se proceni potencijal mikrosatelita da utvrde polimorfizam različitih vrsta pšenice i alelne kombinacije u vezi sa geografskim poreklom. Značajne razlike između grupa pšenice utvrđene su za visinu biljke i vreme klasanja, dok su razlike između tri vegetacione sezone ustanovljene samo za vreme klasanja. Analizom glavnih kordinata razdvojeni su genotipovi pšenice prema poreklu i ploidnosti. Najveće vrednosti pokazatelja molekularnog diverziteta utvrđene su kod tri grupe pšenice: iz Amerike, južne i jugoistočne Evrope, i zapadne i centralne Evrope. Indeks genetičkog identiteta prema Nei-u ukazao je na genetičku sličnost između geografski udaljenih grupa pšenice južne i jugoistočne Evrope i Rusije (0.901) i grupa južne i jugoistočne Evrope i Amerike (0.638). Visok stepen diverziteta visine i vremena klasanja u ocenjenoj kolekciji pšenice predstavlja vredan izvor varijabilnosti za fino podešavanje ovih osobina u oplemenjivanju pšenice u cilju postizanja boljih prinosa u određenim agroekonomskim uslovima.