Diversity for osmotic adjustment and root depth in TEF [Eragrostis tef (Zucc) Trotter]

Osmotic adjustment (OA) and deep roots were shown to be important drought r esistance mechanism in many crop plants. In this study, genotypes systemati cally selected from an Ethiopian endemic tef [Eragrostis tef (Zucc) Trotter ] germplasm pool were evaluated for osmotic adjustment and root depth in gr eenhouse in several experiments. The association of these traits with other plant characters was also studied. Osmotic adjustment was investigated in two experiments. Experiment 1 was conducted using nine genotypes for two se asons (spring and fall 1996), and experiment 2 was undertaken in the spring of 1997 with 45 genotypes. In experiment 1, there were significant genotyp e effects on OA. Though there was also significant genotype by season inter action for OA, some of the extreme lines gave consistently high (Ada and DZ -01-99) and low (DZ-01-354 and Trotteriana) OA values across seasons. There was a significant variation among genotypes for OA in experiment 2. Osmoti c adjustment was not associated with the altitude of the region of origin o f the particular tef genotype. In both experiments, OA was significantly co rrelated across tef genotypes with delayed wilting and the maintenance of h igher relative water content (RWC) under conditions of soil moisture stress . Three experiments were conducted to evaluate the phenotypic diversity for root depth. In all experiments tef genotypes differed significantly for ro ot depth as measured at flowering time. The late maturing genotypes tended to have greater root depth as compared to early maturing genotypes. Root de pth was not associated with the altitude of the region of origin of the tes ted genotypes. There was no association between root depth and OA across ge notypes.