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The genus Trigonella (Fabaceae, tribe Trifolieae) includes potential new species for pasture legume production in phase farming systems of southern Australia. Performance under biotic stress is an important factor in selecting the most suitable species and genotypes for pasture legume breeding programs. Fifty‐nine accessions representing 26 Trigonella species and two Medicago species (formerly with Trigonella) were evaluated for resistance to two aphid species, bluegreen aphid (Acyrthosiphon kondoi Shinji), and spotted alfalfa aphid (Therioaphis trifolii (Monell) fm. maculata) in glasshouse experiments. An accession of Trigonella macrorrhyncha (SA 32223) was found to be highly resistant to both the aphids. Accessions of T. coerulescens, T. cylindracea, T. gladiata, T. mesopotamica, T. schlumbergeri and Medicago monspeliaca were found to be resistant to bluegreen aphid, but susceptible to spotted alfalfa aphid. The resistance mechanism in T. macrorrhyncha involved both antixenosis (non‐preference ...

The Matern correlation function provides great flexibility for modeling spatially correlated random processes in two dimensions, in particular via a smoothness parameter, whose estimation allows data to determine the degree of smoothness of a spatial process. The extension to include anisotropy provides a very general and flexible class of spatial covariance functions that can be used in a model-based approach to geostatistics, in which parameter estimation is achieved via REML and prediction is within the E-BLUP framework. In this article we develop a general class of linear mixed models using an anisotropic Matern class with an extended metric. The approach is illustrated by application to soil salinity data in a rice-growing field in Australia, and to fine-scale soil pH data. It is found that anisotropy is an important aspect of both datasets, emphasizing the value of a straightforward and accessible approach to modeling anisotropy.

Reproductive compatibility was examined among 21 strains of Gymnodinium catenutum derived from four different populations from across the globe: Tasmania, Australia (15 strains), Japan (2 strains). Spain (2 strains) and Portugal (2 strains). Pairwise crossing of strains demonstrated extensive intrapopulation compatibility (to resting cyst formation) among all four populations. The observations were must consistent with a heterothallic, multiple-group mating system. requiring more than two groups to explain the pairwise crossing data. Despite the ability of strains from different populations to produce resting cysts. the viability of progeny was highly variable among interpopulation crosses. Cysts from all crosses showed a high germination percentage (93-100%) and released a swimming planorneiocyte. Crosses between different Tasmanian strains, and those between Spanish and Japanese strains. showed high post-meiotic viability (65% and RO%,respectively). However. progeny from Tasmanian-Spanish and Tasmanian-Japanese crosses showed very low post-meiotic viability (5-10%). indicating a higher level of somatic incompatibility between these populations. Significant differences in sexual life-history (e.g. rate of gamete formation and cyst dormancy) were also noted between interpupulation crosses. suggesting genetically determined strain-and population-level differences. The crossing data indicate a high level of mating diversity within the Australian population and show that the Japanese and Spanish populations are more closely related to each other than to Australian populations: this is supported by molecular studies. implications for the proposed global dispersal of G, catenatum and the use of interbreeding to examine population relationships are discussed. New measures are proposed for examining strain (RCs) and population (Rep) levels of reproductive compatibility, respectively. which are calculated as the product of proportion of successful rnatings (termed the compatibility index) and the number of cysts produced (average vigour) in successful crosses.