Genetic characterization of an Italian Giant Reed (Arundo donax L.) clones collection: exploiting clonal selection

Arundo donax is a perennial rhizomatous plant growing spontaneously all over the world as an invasive plant reaching more than 8 m in height. It is a sterile plant which reproduces itself only agamically, through rhizomes and cane fragments which are transported by water or through human action. Although A. donax is an invasive plant it is considered one of the most promising energy crops, as it is characterized by a high energy balance. In this work we collected 87 A. donax clones from around Italy and with the aim of characterizing the genetic structure of the population, we studied the genetic diversity by using molecular markers (a survey of SSRs and genes from maize) and, for the first time, by sequence comparison using the purple plantl1 maize homologous orthologous gene. The results obtained showed a low genetic diversity as expected for an agamic plant. However, although MANTEL analysis did not show any statistical difference regarding the geographical distribution of these clones, we noticed by PCA/AMOVA analysis the presence of three different genotypes. Among a survey of eight clones studied in detail we found a high correlation between parent-progeny for the traits culm height and culm diameter and a heritability (h2) of the same traits respectively of 0.21 and 0.34 which appeared promising for clonal selection. Finally based on data collected regarding molecular analysis, chromosome number, epidermal cell size and chlorophyll content, we advance the hypothesis that A. donax may be a polyploid derived from Arundo plinii.