Effet des changements environnementaux sur les indicateurs de la sénescence foliaire et son efficacité en tant qu'indicateur pour la sélection de variétés de blé dur (Triticum durum Desf.) en conditions semi- arides

Abstract

In order to determine the effect of environmental changes on leaf senescence parameters in order to test their effectiveness as indicators for the selection of durum wheat varieties in semi-arid conditions, fifteen durum wheat cultivars (Triticum durum Desf.) were sown during 03 cropping seasons 2019-20 and 2020-21 and 2022-23 in the agricultural experimental station of Technical Institute of Field Crops ITGC of Sétif. Both inter-seasonal and inter-annual rainfall variability characterized the three study seasons, the 2019-20 season recorded the best rainfall values with a good distribution of rainy weather. The morpho-agronomic study of two agricultural seasons 2019-20 and 2020-21 showed that the number of grains per spike as well as the weight of a thousand grains were the characters that contributed the most in the development of grain yield, Boutaleb and G10 were the performing varieties during the two study seasons (RDT19- 20= 37.06 – 47.37 Q.ha-1; RDT20-21 = 47.37 - 8.39 Q.ha-1). The curves of the progression of senescence as a function of cumulative temperatures showed that the sigmoidal time course of senescence presented genotypic variability; the sums of temperatures at mid-senescence (∑T50s) differed markedly between the different varieties tested. Boutaleb, G1 and G10 the best profitable cultivars during the two seasons 2020-2021, 2022-23 had slower senescence, they recorded average values of average senescence (Sa) with total réflectance at full heading (Rt), +/- low values of average speed of senescence (Vsa) with high values of cumulative temperatures at mid- senescence (∑T50 s). The results of the monitoring of the chlorophyll contents from the heading stage showed a degradation of the chlorophyll contents during the two cropping seasons. The réflectance averages of the flag leaf during the heading phase showed a great variability on the three RGB bands. Boutaleb, the best cultivar in terms of grain yield during the two cropping seasons 2020-21 and 2022-23 (13.59; 4.76 Q.ha-1) displayed low values of réflectance (R) and (G) and average values of réflectance (B) with average values of chlorophyll contents during the heading phase.