Background:The soybean genome encodes the most expanded plant heterotrimeric G-protein network reported to date. Results: Each G␣ has distinct biochemical properties, and the RGS proteins have different GTPase-activating effects on each G␣. Conclusion:The core G-protein components, their interactions, and biochemical properties are conserved across phyla, but important mechanistic differences exist. Significance: This study provides insight into the complexity of plant G-protein networks.

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ALS-tolerant grain sorghum cultivars are expected to be available for farmers within the next few years. Knowing that: i) crosses between sorghum and shattercane are likely to occur resulting in crop-to-weed gene flow; ii) ALS-susceptible shattercane X ALS-tolerant grain sorghum F1 hybrids (hybrids) were ultimately resistant to ALS-herbicides under field conditions; and iii) hybrid fitness is equal to, or greater than, the wild parent, we conducted a greenhouse study to compare the competitive effect of shattercane and hybrid on sorghum, and whether or not herbicide application would influence the competitive ability of the hybrid plants. An additive design was used where weed densities varied while that of crop remained constant. The treatment design was a factorial with two weedy genotypes, shattercane and hybrid, with the hybrid being either exposed or not exposed to an ALS-herbicide application (nicosulfuron (26.25 g ai ha -1 ) + rimsulfuron (13.16 g ai ha -1 )), and five weed densities (0, 1, 2, 3, and 4 plants pot -1 ). Sorghum density was kept at 1 plant pot -1 . F-tests were performed to compare differences across treatment levels. Shattercane and hybrid produced similar amounts of total above ground biomass within each density, and herbicide exposure did not decrease hybrid biomass production. Moreover, shattercane and hybrid competed similarly with sorghum, and a herbicide application did not reduce the competitive ability of the hybrid. Sorghum wild relatives must be managed by alternative methods before and during the adoption of ALS-tolerant sorghum technology to avoid gene flow and crop yield loss due to competition.

Conservation agriculture (CA) is a management system characterized by zero or minimum tillage, permanent soil cover with crop residue or plant growth, and crop rotation. This study investigated the impact of conservation tillage, crop type, and planting date on crop productivity and the soil physical properties for 2 yr following conversion to CA. After 2 yr, average mean weight diameter of dry aggregates for the 0-to 5-cm and 5-to 10-cm soil depths were 45 and 24% greater in the CA treatment than the conventional practice (CP) treatment, respectively. However, soil sorptivity was about three times slower in CA than in CP for rapeseed (Brassica napus L. toria) rotation treatments, but only 62% slower in CA than CP for wheat (Triticum aestivum L.) rotation treatments. Soil bulk density to a depth of 15 cm was greater in CA (1.30 g cm-3) than CP (1.24 g cm-3), but only for late-planted treatments. Maize (Zea mays L.) yields for CA were not different from CP in the first year, but were 1.4 Mg ha-1 for CA and 5.0 Mg ha-1 for CP in the second year due to poor stand establishment under CA. There were no effects of CA on dry-season rapeseed and wheat. Results suggest that during the transition of CP to CA, soil physical properties can be improved but yields may remain constant or decline. Achieving equivalent yield outcomes between CA and CP will largely depend on equivalent stand establishment.

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