Durum Wheat Root Distribution and Agronomical Performance as Influenced by Soil Properties

To establish the relationship between the soil resistance, depth, and root density of durum wheat (Triticum turgidum L. var. durum) genotypes, the root distribution and penetration performance of 103 genotypes were characterized at three distinct Moroccan fields, namely Safi, Marrakech, and Settat. At each site, a cone penetrometer was used to characterize the penetration resistance profile, and the root distribution was assessed using the horizontal profile method. Marrakech and Safi soils showed a high degree of soil resistance, reaching up to 4 MPa at 170 mm and 220 mm, respectively. In contrast, in Settat soil, 4 MPa resistance was reached at 380 mm, and resistance showed the best linear relationship with depth. Root density decreased with increasing depth. At Settat, the root density of three cultivars was compared at 100, 200, 300, 400, and 500 mm. For the cultivar Haurani, 27% of the roots reached 400 mm, while only 16 and 9% did so for Cham1 and Karim, respectively. Root performance of 103 durum wheat genotypes was assessed at 400 mm depth. Root density varied between 380 and 2568 roots/m(2). In addition, principal component analysis of some agrophysiological parameters for the 103 genotypes showed significant genotypic variation. The early maturing genotypes were dwarf and produced small spikes, and 47% of them exhibited less than 1200 roots/m(2).