Abstract
The diversity of Algerian Saharan wheat is still poorly known. A total of 962 samples, among which farmers identified 57 bread wheat and four durum wheats landraces as well as three mixtures between the two species, were collected in six oases of the Adrar location and four of the Tamanrasset location. Seeds were grown in the Adrar experimental station, and plants were characterized using 15 descriptors related to spike, glume and kernel morphology. Frequency distributions were evaluated and diversity indices (H′) calculated for each descriptor. Polymorphism of descriptors was higher in bread wheat, compared to durum wheat. The highest H′ values were noted for kernel shape, kernel color, awn color, global beak shape and spike density in bread wheat and for awnedness, beak tip shape, hair on spikelet basis and marginal pubescence of the rachis in durum wheat. The frequency distributions significantly varied among landraces for most descriptors. Some also varied within landraces, indicating intra-variability or homonymy. Differences in frequency of distribution were observed between locations and among oases within locations for all descriptors. High diversity indices were noted for most of them. The distribution of phenotypic traits along the Saharan environmental gradient revealed a local adaptation of genotypes to extreme environmental conditions. The study confirmed the peculiarity and high diversity of the Algerian oasis wheat genetic resources and highlighted the importance of preserving them and using them in breeding programs.