Genotypic variation in pre- and post-anthesis dry matter remobilization in Iranian wheat cultivars: associations with stem characters and grain yield

Abstract

The amount of carbohydrate accumulation and remobilization in the wheat stem can be estimated by monitoring changes in stem dry matter. Eighty-one wheat cultivars were examined in the Moghan region of Iran during the 2010–2011 and 2013–2014 growing seasons. Pre- and post-anthesis dry matter remobilization was quantified in the tested cultivars and their associations with stem characteristics and grain yield were investigated. There was substantial variation in stem length, weight, and specific weight among the tested cultivars. The majority of the cultivars did not show pre-anthesis dry matter remobilization in the stem or internodes. In contrast, most of them used stem dry matter that had been stored after anthesis, suggesting that under the given conditions, current photosynthesis along with post-anthesis dry matter remobilization could meet most of the sink demand. Generally, there were no significant associations between stem length and dry matter remobilization (r = –0.05 to 0.03; P ≥ 0.05). Stem weight (r = 0.42 to 0.65; P ≤ 0.01) and specific stem weight (r = 0.44 to 0.60; P ≤ 0.01) measured at 16 days after anthesis correlated positively and significantly with dry weight loss from the stem. Intriguingly, no clear relationships were found between dry matter remobilization and grain yield (r = –0.13 to 0.04; P ≥ 0.05), suggesting that there are no simple relationships between these traits. The association between dry matter remobilization and grain yield may be different depending on the examined cultivars.