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Despite the popularity of bermudagrass (Cynodon dactylon L.) around the world, there are few studies that report genotypic and seasonal variation for sprouting of stolons used in pasture establishment or revegetation of disturbed land. This study investigated the genotypic/seasonal variation and the physiological basis of sprouting from nodes of aboveground stolons among 12 bermudagrasses. Sprouting percentage, total nodes per m (Nds), stolon diameter (SD), total aboveground biomass (TaB), and concentration of water soluble carbohydrate [WSC], concentration of starch [starch], concentration of non-structural carbohydrate [NSC], and concentration of crude protein [CP] were determined in different seasons including winter 2013, winter 2014, spring 2014, summer 2015, and fall 2015. Sprouting percentage for stolons sampled in spring and summer was higher than that for winter and fall. Large genotypic variation for sprouting was observed ranging from 44.1 to 80.2% of all nodes when averaged across seasons. Sprouting percentage among genotypes was strongly associated with SD, TaB, and Nds; and weakly associated with concentrations of photoassimilates such as [WSC], [starch], and [CP] in the aboveground biomass. However, when these photoassimilates were calculated as an amount per node, sprouting percentage was highly correlated with water soluble carbohydrate (WSC) (r = 0.80), crude protein (CP) (r = 0.82), and WSC + CP (r = 0.88). These data suggested that the size and/or maturity of the axillary buds at nodes and the available assimilate supply was underlying the sprouting potential of the bermudagrasses, however, more research under field conditions is required to validate this claim.

A large collection of over 1000 naturalised Australian bermudagrasses (Cynodon dactylon) was assembled. Previous research indicated that a subset of the grasses collected from Australian Mediterranean environments were drought resistant and characterised by large rhizomes that could be a potential source of nutrients, water and carbohydrates when these grasses grow under saline conditions. The objective of this research was to test the salinity tolerance of 12 bermudagrass genotypes with different levels of drought resistance using a flood and drain, sand-solution hydroponic system. Eight salt treatments were imposed ranging from 1.3 to 21 dS m-1 (corresponding 0 to 175 mM NaCl) for up to 17 weeks. Salinity tolerance among genotypes was categorised on the basis of 50% reduction in cumulative clipping yields, verdure and root biomass, and green cover, relative to the control treatment. There was no correlation between salt tolerance and drought resistance (r = -0.079 to 0.572), although some drought-resistant grasses did have excellent salt tolerance, such as entries MED1 and MED3. At 21 dS m-1, most grasses not only maintained over 50% total biomass but also retained over 70% green cover, relative to the control treatment, and were considered as highly salt tolerant. These salt-tolerant grasses have great potential for stabilising and revegetating saline and/or sodic soils.

In Australia, little work has been carried out on the im-provement of tropical or subtropical pastures in recent years. There seems to be an increasing demand for pas-tures that can withstand heavy grazing, while producing high yields of high quality forage in the humid subtropi-cal regions of Australia. Most graziers, who live in these areas, have small acreages, which they graze intensively. Cynodon spp. represent a potential source of grasses with these attributes. This study will evaluate the pasture potential of a large number of bermudagrass (Cynodon spp.) ecotypes collected from across Australia.