Improvement of Upland Rice Variety by Pyramiding Drought Tolerance QTL with Two Major Blast Resistance Genes for Sustainable Rice Production

Varalu is an early maturing rice variety widely grown in the rainfed ecosystem preferred for its grain type and cooking quality. However, the yield of Varalu is substantially low since it is being affected by reproductive drought stress along with the blast disease. The genetic improvement of Varalu was done by introgressing a major yield QTL, qDTY_12.1, along with two major blast resistance genes i.e. Pi54 and Pi1 through marker-assisted backcross breeding. Both traits were transferred till BC₂ generation and intercrossing was followed to pyramid the two traits. Stringent foreground selection was carried out using linked markers as well as peak markers (RM28099, RM28130, RM511 and RM28163) for the targeted QTL (qDTY_12.1), RM206 for Pi54 and RM224 for Pi1. Extensive background selection was done using genome-wide SSR markers. Six best lines (MSM-36, MSM-49, MSM-53, MSM-57, MSM-60 and MSM-63) having qDTY_12.1 and two blast resistance genes in homozygous condition with recurrent parent genome of 95.0%-96.5% having minimal linkage drag of about 0.1 to 0.7 Mb were identified. These lines showed yield advantage under drought stress as well as irrigated conditions. MSM-36 showed better performance in the national coordinated trials conducted across India, which indicated that improved lines of Varalu expected to replace Varalu and may have an important role in sustaining rice production. The present study demonstrated the successful marker-assisted pyramiding strategy for introgression of genes/QTLs conferring biotic stress resistance and yield under abiotic stress in rice.     

Comparative sorption of copper and nickel from aqueous solutions by natural neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) sawdust and acid treated sawdust

This study investigates the potential use of neem (Azadirachta indica) sawdust treated with hydrochloric acid for the removal of copper (II) and nickel (II) ions from wastewater. The effects of different system variables, viz, adsorbent dosage, initial metal ion concentration, pH and contact time were studied. The results showed that as the amount of the adsorbent was increased, the percentage of metal ion removal increased accordingly. Optimum pH value for metal adsorption is determined as 5.0 for Cu (II) and 4.0 for Ni (II) ions. Maximum metal is sequestered in 150 min for Cu (II) and 180 min for Ni (II) after the beginning of every experiment. Similar experiments were carried out with acid treated sawdust to compare the results. The adsorption of metal ions followed a first order rate equation. Both Freundlich and Langmuir adsorption models are suitable for describing the sorption of Cu (II) and Ni (II) on the two forms of sawdust. Furthermore, the natural organic matter (neem sawdust) is characterized by FTIR spectra and surface area analysis. At optimal conditions the maximum adsorption capacity is found to be 48.3 and 286 mg/g for Cu (II) and 31.5 and 74.1 mg/g for Ni (II) in natural and acid treated forms, respectively.     

Stem and leaf rust resistance in wild relatives of wheat with D genome (Aegilops spp.)

Resistance to stem rust and leaf rust in five D genome species of wheat viz., 267 accessions of Aegilops tauschii Coss., 39 of Ae. cylindrica Host, 17 of Ae. ventricosa Tausch, 4 of Ae. crassa Boiss. and 8 of Ae. juvenalis (Thell.) Eig were evaluated at adult plant stage. Two hundred and thirty nine (90 %) accessions of Ae. tauschii, 30 (77 %) of Ae. cylindrica, 16 (94 %) of Ae. ventricosa, 3 (75 %) of Ae. crassa Boiss. and 5 (62.5 %) of Ae. juvenalis were resistant to stem rust pathotypes prevalent in South India at Wellington under field condition. Invariably, all the accessions of the five species were resistant to leaf rust pathotypes. Quantitative measurement of disease using area under the disease progress curve revealed the slow progress of disease in the resistant accessions compared to susceptible check (Agra Local). Since all the five species have D genome, it could be concluded that the genes present in D genome might play a vital role in leaf rust resistance, but in case of stem rust resistance wide range of differential response was noticed. Among the species evaluated, Ae. tauschii was exploited to a larger extent, followed by Ae. ventricosa and Ae. cylindrica for leaf and stem rust resistance because of the homology of D genome with hexaploid bread wheat. While, Ae. crassa and Ae. juvenalis could not be utilized so far, possibly due to partial homology which makes the transfer of traits difficult. So, these species have considerable potential as a source of rust resistance and may enhance the existing gene pool of resistance to stem and leaf rusts.     

Some properties of beta-D-galactosidase from the adult filarial nematode Setaria digitata

beta-D-galactosidase (beta-D-galactoside galactohydrolase, E.C. 3.2.1.23) activity was localised in the digestive tract of Setaria digitata. The enzyme extract shows maximum activity in the pH range between 3.5 and 5.0 and at 45 degrees C. The enzyme shows the Km value of 3.636 mM for the substrate 6-bromo-2-naphthyl beta-D-galactoside and Vmax of 28.57 nmol 6-bromo-2-naphthol liberated mg-1 protein min-1. Activation/inhibition of the enzyme by various ions, medicinal plants and drugs has been studied. Polyacrylamide gel electrophoresis revealed that the enzyme exists as single form. The medicinal plants and the drug filarin effectively inhibit the enzyme. The significance of these results are discussed in relation to chemotherapy.     

Comparison of organic and conventional farming for onion yield,biochemical quality,soil organic carbon,and microbial population

In an ongoing field experiment, organic and conventional farming (control) were compared for onion bulb yield, biochemical quality, soil organic carbon (SOC), and microbial activity after the sixth cropping cycle. The treatments used for organic production were farmyard manure (FYM, 20,000 kg ha^?1), poultry manure (PM, 10,000 kg ha^?1), vermicompost (VC, 10,000 kg ha^?1), neem cake (NC, 5000 kg ha^?1), and a combination of FYM (5000 kg ha^?1), PM (2500 kg ha^?1), VC (2500 kg ha^?1), and NC (1250 kg ha^?1); all treatments were compared with the control. Organic treatments produced 24.6–43.6% lower yield consistently for 6 years than the control treatment. No significant difference was observed between PM, FYM, and VC treatments for the bulb yield. Bulb analysis during the sixth year indicated that plants that received FYM, PM, or VC had higher levels of total phenol, total flavonoid, ascorbic acid, and quercetin-3-glucoside than the control plants. All the five organically treated sets had significantly higher values of SOC, microbial population, fungal-to-bacterial ratio, and dehydrogenase activity than the control and the initial values in each treated set. The results indicate that FYM, PM, or VC application enhances biochemical quality and organic farming is more sustainable than conventional farming.