Wujun Ma

Optimising Nitrogen fertiliser management and using cultivars with high Nitrogen uptake and utilisation efficiency is a good strategy to improve the Nitrogen use efficiency (NUE). This study investigates the determinants of genetic variation in NUE and develops associations with NAM - A1 and NAM - B1 alleles in Australian wheat cultivars grown under different N treatments in Westonia Australia. The functional NAM - B1 allele improves nitrogen remobilization from the leaf tissue, which led to increasing grain protein content but reduces the grain yield. NAM - A1a allele has the same functional of NAM - B1, but with more influence on the period of grain filling. The Nitrogen fertiliser treatments were applied at rates (0, 50, and 100 kg N ha −1) at three stages (Mid Tillering, Booting, and Flowering) of plant growth. The following parameters were analysed: grain yield, number of head plant - 1, number of seed head - 1, thousand grain weight, Root dry weight, total NAM gene expression, grain protein content, residual N in straw, and Nitrogen content in leaf tissue to determine the Nitrogen accumulation and translocation from the leaves to the grain, and overall NUE and its component. The increase of Nitrogen application also resulted in increased grain yield, number of head plant - 1, and greater root dry weight, which was highest at 100 kg N ha −1. The timing of Nitrogen application had no clear effect on either grain yield or grain protein content. Application of Nitrogen at the late stage (booting and flowering) increased the only number of seed head - 1 and thousand grain weight. The duration of grain filling was critical on Australian wheat cultivars and had a strong impact on grain yield and grain protein content. Our results indicated that NAM - A1 alleles are significantly related to the length of the grain filling period. NAM - A1 allele a is associated with early and early to mid grain filling duration, while NAM - A1 alleles c and d associated with mid and mid to late grain filling duration.

Narrow-leafed lupin (NLL) is one of the major legume crops in Australian farming system which is largely used as animal feed. A number of modern cultivars have been developed through breeding making NLL possible to be consumed as human food. Significant health benefits have been recognised when NLL seeds are consumed. This study characterised protein polymorphism among the 25 Australian cultivars through mass spectrometric (MALDI-TOF) with the aim of developing molecular breeding strategies to improve protein quality and content. Altogether, 364 seed storage proteins were identified by the MALDI-TOF profiling and fifty proteins were cultivar specific. Nine common proteins (present in all cultivars) and 61 rare proteins (present in 2–3 cultivars only) were recorded. Phylogenic analysis based on the protein profile clustered the cultivars into 2 major groups and 5 subgroups which are generally supported by the pedigree information. Small number (2.4%) of common proteins among the cultivars suggested a high level of genetic diversity in seed storage protein of NLL.