Abstract
This study was conducted to assess the variability of seed traits in homologous pairs of five Acacia species, i.e., A. asak, A. ehrenbergiana, A. etbaica, A. gerrardii and A. origena, which are naturally distributed in two areas of Saudi Arabia: Asser and Al Baha. Seed traits included length, width, thickness, volume, seed coat thickness and weight, and endosperm weight. The number of intact, infected, and decomposed seeds in the soil were determined too.
Significant spatial differences were observed regarding seed volume, seed coat thickness and infected seeds; these three traits were higher in Asser. The widths of A. asak, A. ehrenbergiana, A. etbaica, and A. gerrardii seeds were significantly different between the two locations, with higher values found in Asser. Significant differences in the number of decomposed seeds were found for A. asak, A. etbaica, A. gerrardii and A. origena. Significant variations in seed length were found for A. asak, A. etbaica and A. origena; the seeds tended to be longer in Asser. Seed thickness varied significantly for A. asak, A. etbaica, and A. origena; A. asak and A. etbaica tended to have thicker seeds in Asser. The total seed weight was significantly different for A. ehrenbergiana, A. etbaica and A. origena. Acacia etbaica and A. origena seeds were heavier in Al Baha. The numbers of intact A. ehrenbergiana, A. gerrardii and A. origena seeds were significantly different. Furthermore, the endosperm weight varied significantly for A. etbaica and A. origena with higher weights being observed in Al Baha. The seed coat weight varied only in A. origena.