Chickpea

The narrow genetic base of cultivated chickpea warrants systematic collection, documentation and evaluation of chickpea germplasm and particularly wild Cicer species for effective and efficient use in chickpea breeding programmes. Limiting factors to crop production, possible solutions and ways to overcome them, importance of wild relatives and barriers to alien gene introgression and strategies to overcome them and traits for base broadening have been discussed. It has been clearly demonstrated that resistance to major biotic and abiotic stresses can be successfully introgressed from the primary gene pool comprising progenitor species. However, many desirable traits including high degree of resistance to multiple stresses that are present in the species belonging to secondary and tertiary gene pools can also be introgressed by using special techniques to overcome pre- and post-fertilization barriers. Besides resistance to various biotic and abiotic stresses, the yield QTLs have also been introgressed from wild Cicer species to cultivated varieties. Status and importance of molecular markers, genome mapping and genomic tools for chickpea improvement are elaborated. Because of major genes for various biotic and abiotic stresses, the transfer of agronomically important traits into elite cultivars has been made easy and practical through marker-assisted selection and marker-assisted backcross. The usefulness of molecular markers such as SSR and SNP for the construction of high-density genetic maps of chickpea and for the identification of genes/QTLs for stress resistance, quality and yield contributing traits has also been discussed

Dispersal of conidia of Ascochyta fabae f. sp. lentis from infected lentil plants by simulated wind and rain

Splash was shown to be an effective mechanism for short-range dispersal of conidia of Ascochyta fabae f. sp. lentis, the cause of ascochyta blight of lentil. The dispersal gradients were well described by the power law model in its linear form, 1ny = 1na - b 1nx. In still air the slope of the linearized dispersal gradient, b, ranged from 2.83 to 4.07 and was steeper for 4.9 mm than for 3.9 mm incident drops. Nevertheless, for all drop sizes tested, fewer than 50% of the conidia were splashed more than 15 cm from the source. The pattern of conidium dispersal was similar for both drop sizes when horizontal windspeeds were 2.5 or 5 mis. Wind significantly decreased the value of b (range 2.35-2.43 at 25 m/s, 1.71-1.91 at 5 m/s) and increased by about 2 m the maximum distance that conidia in ballistic droplets were deposited. In addition, the experiments suggested two other potentially important mechanisms for dispersal of the pathogen over longer distances, namely conidia in small air-borne droplets and windblown leaflets.Peer reviewe

Relationships between temperature, bleaching and white syndrome on the Great Barrier Reef

Coral bleaching and disease have often been hypothesized to be mutually reinforcing or co-occurring, but much of the research supporting this has only drawn an implicit connection through common environmental predictors. In this study, we examine whether an explicit relationship between white syndrome and bleaching exists using assemblage-level monitoring data from up to 112 sites on reef slopes spread throughout the Great Barrier Reef over 11 years of monitoring. None of the temperature metrics commonly used to predict mass bleaching performed strongly when applied to these data. Furthermore, the inclusion of bleaching as a predictor did not improve model skill over baseline models for predicting white syndrome. Similarly, the inclusion of white syndrome as a predictor did not improve models of bleaching. Evidence for spatial co-occurrence of bleaching and white syndrome at the assemblage level in this data set was also very weak. These results suggest the hypothesized relationship between bleaching and disease events may be weaker than previously thought, and more likely to be driven by common responses to environmental stressors, rather than directly facilitating one another