Individual and interactive effects of cultivar maturation time, nitrogen regime and temperature level on accumulation of wheat grain proteins.

BACKGROUND: Background and reasons for differences in wheat grain protein accumulation and polymerization are not fully understood. This study investigated individual and interactive effects of genetic and environmental factors on wheat grain protein accumulation and amount and size distribution of polymeric proteins (ASPP).
RESULTS: Individual factors, e.g. maturation time of a cultivar, nitrogen regime and temperature level, influenced grain protein accumulation and ASPP, although interaction of these factors had a greater influence. Early maturation time and long grain maturation period (GMP) in a cultivar resulted in high amounts of sodium dodecyl sulphate (SDS)-extractable proteins (TOTE) and low percentage of SDS-unextractable polymeric proteins in total polymeric proteins (%UPP). Cultivars with late maturation time and short GMP resulted in low TOTE and high %UPP. Late versus early nitrogen application regime resulted in low %UPP versus low TOTE and high %UPP, respectively. High versus low temperature resulted in high %UPP and low %UPP, respectively. Differences in ASPP at maturity started as changes in protein accumulation from 12 days after anthesis.
CONCLUSION: Length of GMP, especially in relation to length until maturity, governs gluten strength (%UPP) and grain protein concentration (TOTE). Length of GMP is determined by cultivar, temperature during GMP and late nitrogen availability.