Accumulation and remobilization of assimilates in different genotypes of durum wheat under terminal drought stress

The present research was conducted to examine the accumulation and remobilization of some promising lines of durum wheat assimilates using a randomized complete block design. In this regard, two experimental groups of stress and normal (no stress) with three replications were compared during two crop years. The analysis of the results included measuring the accumulation and remobilization rates of assimilates using the weighting method as well as investigating the relationship between internode characteristics (length and specific weight) and dry matter accumulation. The obtained results were indicative of a significant difference among various genotypes considering the contribution of different internodes to the stem length under normal and stress conditions. In all genotypes, the peduncle internode had the largest contribution to the stem height. Under both conditions, the lower internodes had the highest remobilization as well as dry and specific weights. The highest rate of remobilization from the lower internodes was detected in G2 genotype under normal and G7, G18, and G6 genotypes under stress conditions. Moreover, the highest remobilization efficiency from the lower internodes was observed in G7 and G18 genotypes under stress conditions. The obtained results were indicative of two different mechanisms of storage capacity and remobilization ability. As observed, the G14 line was one of the genotypes that revealed the highest specific weight of peduncle while the rate of remobilization was the lowest in response to stress conditions. The highest rates for the specific weight of the lower internodes with the lowest rates of remobilization were observed in G4 and G8 lines. According to the results, the wide variation for the accumulation and remobilization of assimilates among the durum wheat genotypes can pave the way for possible trait changes in breeding programs.