Influences of weather, cultivar and fertiliser rate on grain protein polymer accumulation in field-grown winter wheat, and relations to grain water content and falling number

摘要

The reasons for variations in the amount and size distribution of polymeric protein in mature wheat, related to bread-making quality, are not fully understood and can be sought during the protein polymer formation period of grain maturation. The present study was aimed at investigating the accumulation and polymerisation of grain storage proteins during grain maturation and their relations to changes in falling number and grain water content in four cultivars of field-grown winter wheat.RESULTS: Proteins were accumulated and polymerised similarly during grain development independently of cultivation environment, cultivar and fertiliser rate. A 3-6 day delay in maturity among cultivars led to a 3-12 day delay in protein accumulation during early grain development. An increase in nitrogen fertiliser rate from 160 to 200 kg N hap# resulted in a 20% increase in the amount of sodium dodecyl sulfate (SDS)-unextractable protein. Precipitation just before grain harvesting led to 40-50% increases in grain water content and 8-34% decreases in the amount of SDS-unextractable monomeric protein. At increased grain water contents the fertiliser rate was negatively related to the amount of grain SDS-unextractable protein.CONCLUSION: Accumulation and polymerisation of grain storage proteins are predetermined events in wheat. Grain moisture content is negatively related to grain storage protein polymerisation, although the rate of decrease is influenced by the fertiliser regime. Copyright