IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
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17 th <strong>International</strong> Congress on <strong>Nitrogen</strong> <strong>Fixation</strong><br />
Fremantle, Western Australia<br />
27 November – 1 December 2011<br />
Title Development of an inoculant for Acacia acuminata to improve growth of Santalum spicatum<br />
Authors Elizabeth Watkin 1 , Len Norris 2, 3 , Liz Barbour 2,4<br />
Poster Board Number 33<br />
1 School of Biomedical Sciences, Curtin University<br />
2 Forest Products Commission<br />
3 Department of Agriculture & Food WA<br />
4 Faculty of Natural and Agricultural Sciences, The University of Western Australia<br />
Acacia acuminata is the most widely used host species within commercial plantations of the hemi-parasitic<br />
species Santalum spicatum (West Australian sandalwood). Some 10 thousand hectares of WA sandalwood<br />
plantations have been established in the 400 to 600 mm rainfall zone of the wheat-belt to supplement future<br />
shortfalls in West Australian sandalwood supply resulting from native harvest restrictions and increase in world<br />
demand. Host selection trials in WA demonstrated that leguminous N-fixing species are superior compared to<br />
non N-fixing species, with A. acuminata being a superior choice across a range of environments. Improving Nfixation<br />
of A. acuminata was identified as a potential factor to increase sandalwood productivity.<br />
This study aimed to develop a high-performing N-fixing inoculant for application to A. acuminata seedlings in<br />
nurseries or directly onto seeds. Seventeen root nodule bacteria isolates previously identified as being effective<br />
on A. acuminata were used to inoculate five different A. acuminata provenances to test their effectiveness in a<br />
containerised nursery environment. Isolates were ranked on their ability to increase seedling growth over an uninoculated<br />
control. Based on the results of this trial, five inoculum treatments were prepared with combinations of<br />
the most effective isolates. All five treatments produced significantly larger seedlings than the control. Higher<br />
total nodule mass had a stronger relationship with seedling growth, than nodule size alone. All isolates were<br />
demonstrated to be Bradyrhizobium spp. based on 16 S rRNA gene sequencing.<br />
These isolates are a valuable resource to further investigate the impact of efficient N-fixation in A. acuminata on<br />
the vigour and heartwood production in WA sandalwood. Greater N-fixation efficiency through a seed or nurseryapplied<br />
inoculant may enable the host to survive greater parasitic loading. Thus superior inoculant treatment<br />
could improve the supply of nutrients for increased sandalwood growth or reduce host mortality within a<br />
plantation and subsequent sandalwood death.<br />
148<br />
2011