Evolving high yielding rice genotypes with durable resistance to bacterial leaf blight (BLB) is pertinent considering the extensive damage caused by the disease in most of the rice growing regions. Two high yielding BLB susceptible indica rice cultivars, ÔADT43Õ and ÔASD16Õ popular among farmers and consumers across South India have been introgressed with three BLB resistance genes xa5, xa13 and Xa21 from isoline IRBB60 using functional markers. The F 2 populations of 500 plants from ADT43 · IRBB60 and 806 plants from ASD16 · IRBB60 crosses were screened for the presence of all the three resistance genes. Thirty genotypes with three genes in homozygous and 55 genotypes with two genes in homozygous and one gene in heterozygous condition were identified. These pyramided genotypes with two or three resistance genes exhibited high levels of resistance against two predominant Xanthomonas oryzae isolates of South India. Among the 30 pyramided genotypes (xa5 + xa13 + Xa21), 12 were found to be significantly high yielding with desirable agronomic characteristics and the selection efficiency of the present markers was hundred percent.

Mungbean yellow mosaic virus (MYMV) disease is one of the most vicious diseases of green gram and has been renowned in India for more than five decades. It is caused by a group of geminiviruses belonging to the genus, begomovirus of the family, Geminiviridae. They are transmitted through whitefly in a persistent manner. The economic losses due to this virus account up to 85% in green gram which is spreading faster towards newer areas. The escalating economic importance of MYMV has resulted in the call for accurate detection and identification procedures that inspire rigorous research efforts focussing on the biology, diversity and epidemiology of the virus, so that viable management strategies could be designed. Breeding for resistance or tolerance appears to be the best approach to control this disease. However, the commercially offered genotypes are only partially resistant. Therefore, the hunt for newer sources of disease resistance needs to be intensified. This review updates all the accessible information on MYMV and outlines the areas in which advance research is indispensable.

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The objective of this research was to study the mode of inheritance of resistance to mungbean yellow mosaic virus (MYMV) in inter TNAU RED × VRM (Gg) 1 and intra KMG 189 × VBN (Gg) 2 specific crosses of mungbean. An infector row technique was used for evaluating parents, F 1 , F 2 and F 3 plants for MYMV resistance. No insecticide was sprayed in order to maintain the natural whitefly population in experimental field. In the field condition, only after 80% of plants showed MYMV incidence, and the scoring of the test materials was done by MYMV disease rating scale. According to the mean disease score, the mungbean genotypes were categorized into five groups resistant (R), moderately resistant (MR), moderately susceptible (MS), susceptible (S) and highly susceptible (HS). 3 (Susceptible): 1 (Resistance) was observed in all two crosses of all F 2 population and it showed that the dominance of susceptibility over the resistance and the results of the F 3 segregation (1:2:1) confirm the segregation pattern of the F 2 segregation. Collectively all the two crosses F 2 and F 3 generations results suggested that a single recessive gene is involved in resistance against the MYMV disease.

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The fluvio‐tidal transition of suspended sediment in terms of mineralogy and composition in the Loire River drainage basin, the largest French river basin, was investigated in the fluvial zone at Montjean and in the tidal zone at Mauves‐Thouaré, for a complete seasonal cycle. At Montjean, where the river experiences unidirectional flow, the composition and mineralogy (especially clays and clay minerals) of river suspended material (RSM) are governed by the river discharge, upstream contributions, climatic conditions and microbiological activities. However, due to reversing tidal and river currents at Thouaré, in the zone of tidal dynamics, these relations are changed. In the downstream direction sand and clay content in the RSM decrease while the silt content increases. Among clay minerals, between these two observation stations, montmorillonite remains constant, kaolinite diminishes, and the other minerals increase downstream. Combustible material (organic) and nitrate (NO3) contents in the RSM increase whereas the phosphate (PO43‐) and CaCO3 contents decline considerably during transport. At the head of the tidal zone, where the river flow encounters the tidal influence, there is a relatively stationary water mass (tidal slack) where sands, clays, phosphate, carbonate and silica are deposited by physical and chemical processes. Physical sedimentation takes place by simple gravitational deposition (sands), and by sorting and complicated differential settling (clays); chemical sedimentation takes place by precipitation (calcite‐CaCO3; apatite‐Ca5 (PO4)3 (OH,F,Cl); coagulation of dissolved silica‐SiO2) in connection with seasonal algal bloom and eutrophic events.

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