Remobilization of Pre‐Anthesis Assimilates to the Grain for Grain Only and Dual‐Purpose (Forage and Grain) Triticale

Abstract

AbstractIn Mediterranean environments, translocation of pre‐anthesis assimilates to the grain is an important source of photosynthates. In this work, the effect of forage removal at the beginning of jointing on the amount of dry matter (DM) accumulated before anthesis and remobilized during grain filling was studied in five spring and five winter triticale genotypes (×Triticosecale Wittmack). Field experiments were conducted in 1992 and 1993 in northeastern Spain. Two harvesting treatments were used: (i) grain production only and (ii) cutting the crop for forage at the beginning of jointing and harvesting the grain produced after regrowth. Pre‐anthesis storage of carbohydrates was very important to grain filling in triticale, both for grain and for dual‐purpose. Contribution of pre‐anthesis assimilates to grain yield in the uncut plots was 46% in spring triticale genotypes and 65% in winter genotypes, as the later‐maturity winter triticale genotypes were more affected by terminal abiotic stresses. Reductions in DM accumulated at anthesis after forage removal were more pronounced in winter genotypes (39%) than in spring genotypes (20%), where an earlier development allowed for a longer recovery period after cutting; DM reductions were similar to grain yield decreases. The effect of forage removal on translocation depended on the growth hbit of the genotype and environmental conditions. Most differences were associated with changes in crop phenology. In spring types, with early jointing, DM translocation and the contribution of pre‐anthesis assimilates to grain were not affected by forage removal, whereas both traits were drastically reduced in winter triticale. Most differences in 13C/12C carbon isotope discrimination (Δ) in grains were also phenology driven.