Salt tolerant Durum wheat
A numerical scale has been used to indicate resistance levels in Table 1 below:
1-3 (Very low) - high levels of disease may occur with substantial yield losses.
4-5 (Low) - disease may be evident in favourable situations with moderate yield losses.
6-7 (Medium) - some disease may develop in favourable conditions, some yield loss may occur.
8-9 (High) - indicates a high level of resistance and grain yield is unlikely to be reduced.
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- NSW DPI data used for Jandaroi. QPIF data used for all other varieties.
- Root Lesion Nematode tolerance applies to Pratylenchus thornei and not Pratylenchus neglectus; tolerant varieties yield well in the presence of RLN; resistant varieties prevent RLN reproduction.
- Black point will not cause a reduction in yield but may result in grain receiving a lower quality classification.
Durum wheats are very susceptible to crown rot caused by the fungus Fusarium pseudograminearum. The most conspicuous symptom of crown rot is the appearance of ‘white heads’ or ‘deadheads’ in the crop. The stem bases of diseased plants are a honey-brown colour and on severely affected plants, a pink fungal growth may be present on the lower part of the crown.
Grain yield and quality
Initial trials indicate durum wheat yields to be similar or slightly less than bread wheats. Grain quality is very important in obtaining premium prices. Downgrading may occur if grain contains mottling, black point or weather damage.
Black Point on grain
Highest premiums are paid for plump, hard, vitreous grain that is free from mottling. Mottled grain is the result of low grain protein. Grain protein levels are a function of available soil nitrogen. The application of nitrogenous fertiliser may be necessary but this cost needs to be offset by the higher premium payments and increased yield. A small percentage of mottled grains can be tolerated in the top grade but more than 10% (see Table 2) will result in downgrading and a reduced premium.
Black point is a dark discolouration at the germ end of otherwise healthy grain. In wheat the discolouration occurs in the outer portions of the seed and in some severe cases may extend along the groove on the underside of the grain.
Downgrading is on the basis of visual appearance and there is very little information on the effect, on end-product quality. When discolouration extends along the groove there is the potential for undesirable dark specks in the semolina and/or a speckled appearance in end-products. The current durum varieties, particularly Wollaroi and EGA Bellaroi, offer better resistance to black point than previous varieties. However, because the dockage limit for DR1 is 3% (see Table 2), this premium grade may be difficult to achieve when humid grain ripening conditions occur.
Although durums have slightly better resistance to pre-harvest sprouting than current bread wheats, they may be downgraded to feed due to bleaching and softening of the grain.
