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Background Medicago truncatula Gaertn. (barrel medic) is cultivated as a pasture legume for its high protein content and ability to improve soils through nitrogen fixation. Toxic concentrations of the micronutrient Boron (B) in agricultural soils hamper the production of cereal and leguminous crops. In cereals, the genetic analysis of B tolerance has led to the development of molecular selection tools to introgress and maintain the B tolerance trait in breeding lines. There is a comparable need for selection tools in legumes that grow on these toxic soils, often in rotation with cereals. Results Genetic variation for B tolerance in Medicago truncatula was utilised to generate two F 2 populations from crosses between tolerant and intolerant parents. Phenotyping under B stress revealed a close correlation between B tolerance and biomass production and a segregation ratio explained by a single dominant locus. M . truncatula homologues of the Arabidopsis major intrinsic protein (MIP) gene AtNIP5;1 and the efflux-type transporter gene AtBOR1 , both known for B transport, were identified and nearby molecular markers screened across F 2 lines to verify linkage with the B-tolerant phenotype. Most (95%) of the phenotypic variation could be explained by the SSR markers h2_6e22a and h2_21b19a , which flank a cluster of five predicted MIP genes on chromosome 4. Three CAPS markers ( MtBtol-1,-2 , -3 ) were developed to dissect the region further. Expression analysis of the five predicted MIPs indicated that only MtNIP3 was expressed when leaf tissue and roots were assessed. MtNIP3 showed low and equal expression in the roots of tolerant and intolerant lines but a 4-fold higher expression level in the leaves of B-tolerant cultivars. The expression profile correlates closely with the B concentration measured in the leaves and roots of tolerant and intolerant plants. Whereas no significant difference in B concentration exists between roots of tolerant and intolerant plants, the B concentration in the leaves of tolerant plants is less than half that of intolerant plants, which further supports MtNIP3 as the best candidate for the tolerance trait-defining gene in Medicago truncatula . Conclusion The close linkage of the MtNIP3 locus to B toxicity tolerance provides a source of molecular selection tools to pasture breeding programs. The economical importance of the locus warrants further investigation of the individual members of the MIP gene cluster in other pasture and in grain legumes.

We calculate financial risk profiles for representative vineyards of 50-ha in four wine grape regions of South Australia using straw or living mulches as alternatives to herbicides for under-vine management. Calculations are based on replicated experiments in a commercial vineyard in each district with the most widely grown vine variety of each; the grape yields were measured in 2016 and 2017. Published district grape prices and yields for the years 2006 through 2017 form the basis for novel stochastic analysis. The herbicide (Control) treatment in Barossa Shiraz (BS) and Riverland Merlot (RM) showed greater median Gross Revenues (prices x yields) than the other two districts: Eden Valley Shiraz and Langhorne Creek Cab-Sav. After subtraction of operating costs, and assuming alternative treatments produce grapes of equal quality and price as the Control in a district, the alternatives gave median Gross Margins ( $/ha) greater than the Control in BS but lower than the Control in RM. Gross Margin results were mixed in the other two districts. The Gross Margin results above are magnified in financial Risk Profiles based on variations in Gross Margins times 50 ha across multiple ten-year periods after subtracting taxes, drawings, recurrent capital costs and interest on accumulating debt, for decadal cash margins. The Risk Profile of a treatment in a district is its cumulative distribution of decadal cash margins ($ M). We show that choice of under-vine treatment can significantly affect a vineyard's financial viability.

Optical tracking systems typically trade-off between astrometric precision and field-of-view. In this work, we showcase a networked approach to optical tracking using very wide field-of-view imagers that have relatively low astrometric precision on the scheduled OSIRIS-REx slingshot manoeuvre around Earth on September 22nd, 2017. As part of a trajectory designed to get OSIRIS-REx to NEO 101955 Bennu, this flyby event was viewed from 13 remote sensors spread across Australia and New Zealand to promote triangulatable observations. Each observatory in this portable network was constructed to be as lightweight and portable as possible, with hardware based off the successful design of the Desert Fireball Network. Over a 4 hour collection window, we gathered 15,439 images of the night sky in the predicted direction of the OSIRIS-REx spacecraft. Using a specially developed streak detection and orbit determination data pipeline, we detected 2,090 line-of-sight observations. Our fitted orbit was determined to be within about 10~km of orbital telemetry along the observed 109,262~km length of OSIRIS-REx trajectory, and thus demonstrating the impressive capability of a networked approach to SSA.