Etude comparative de l 'influence des diff erents genotypes de l'orge (Hordeum vulgare L.) sur la sequestration du carbone organique du sol et sur la resistance a la secheresse

Abstract

Barley (Hordeum vulgare L.) is a diploid species (2n = 2x = 14) and one of the four most important cereal crops in the world after rice, wheat and maize. These cereals are mainly used for animal feed, malt production and human consumption. Due to its wide environmental range, end-uses and wide variety of uses, barley has become an excellent model for studying and responding to the impacts of various climate change scenarios. The present work deals with two major aspects: the first concerns the identification through the agronomic study of barley, a genotypes performing from 30 varieties used optimizing the sequestration of soil organic carbon. The second aspect aims to determine for the same varieties the correlation between the architecture of the root system and the resistance to drought in the species in order to select genotypes with sustainable productivity by mobilizing the resources of a dry environment such as the Moroccan context. Descriptive analyzes showed significant differences between genotypes for morphological traits (plant height, flag leaf and spike length), productivity traits (number of tillers, total biomass and root biomass), root angle and sequestration of soil organic carbon. Moreover, variance analyzes (ANOVA) revealed highly significant differences between the genotypes for all of the above characters except carbon sequestration. The correlation matrix recorded highly significant correlations between productivity traits, but no significant correlation was found between these traits and root architecture (root angle), or even sequestration of soil organic carbon. Principal component analysis (ACP) revealed four groups of homogenous genotypes for most of the characters mentioned, and this grouping was confirmed by the euclidean distance dendrogram. A negative correlation between root angle and resistance to water stress led to the identification of three major groups of genotypes with different behaviors: conservative, intermediate conservation and no or little conservative