Post-anthesis dry matter dynamics in the internodes of wheat cultivars grown under contrasting conditions: associations among agro-physiological traits

Abstract

Methodological problems in measuring carbohydrate accumulation and remobilization in wheat stem have led to inconsistent results. However, the assessment of an individual internode eliminates the underestimated accumulation and remobilization, and accordingly, improves their accurate calculation. Therefore, the present study aimed at measuring the amount of dry matter accumulation and remobilization in different internodes, as well as evaluating the possible associations between the two parameters at the internode level. Moreover, the influence of the stored reserves on the grain yield of wheat cultivars grown under contrasting conditions was examined. Eighteen cultivars were evaluated under well-watered (WW) and terminal drought stress (DS) conditions at a Mediterranean climate during 2007–2009, as well as under WW conditions in a subtropical climate during 2014–2015. Time-dependent changes in the weights of the internodes were measured after anthesis. The highest mean of dry matter accumulation and remobilization and contribution percentage of reserves to grain yield were observed in the lower internodes, followed by the penultimate and peduncle. The maximum weight of each stem internode generally correlated positively with the remobilized dry matter of that internode. Grain weight per spike was not related to dry matter remobilization of the internodes under all WW conditions. However, a significantly positive correlation was found between this trait and dry matter remobilization of the lower internodes under DS condition of the Mediterranean climate. Interestingly, the significant association was refuted by employing stem remobilization in the analysis, indicating the importance of the internode level in studying such associations.