Leaf Rust Infection in Homogeneous and Heterogeneous Populations of Bread Wheat

Three commercial Indian wheat varieties —‘Sonalika’, ‘Kalyansona’ and ‘Janak’ were used to develop homogeneous and heterogeneous lines for leaf rust resistance, utilizing diverse sources of resistance from fourteen donors. Four kinds of multilines were developed to study coefficients o: infection, areas under disease progress curves (AUDPC), rates of spread and grain yields over their component means. Heterogeneous populations showed minimum coefficients of infection at initial as well as final stages, which were less than or equal to the resistant component even in dirty multilines carrying up to 50 % susceptible populations. Large reductions in coefficients of infection and in AUDPC were also observed. Rate of spread was independent of coefficient of infection and AUDPC. Grain yield advantage over both component means and recurrent parents was higher in clean multilines. The significance of the use of multilines in limiting losses due to disease is discussed.     

Gharials (Gavialis gangeticus) in Bardiya National Park,Nepal: Population,habitat and threats

1. The Critically Endangered gharial (Gavialis gangeticus) residing within Bardiya National Park (BNP) in Nepal constitutes the sixth major sub-population of this unique lineage; however, this population is not well studied. A 46 km protected stretch of the Babai River and a 60 km stretch of the Karnali River in and around BNP were surveyed for gharials in early 2017 and in 2019.
2. Gharial counts in 2017 – 17 from the Babai and one from the Karnali rivers – consisted of 10 adults, five sub-adults and three juveniles. In 2019, 19 gharials were counted – 18 for the Babai and one for the Karnali – comprising 11 adults, six sub-adults and two juveniles. In the Babai River within BNP, four breeding groups were identified. Gharials in BNP prefer sandy vs. rocky banks for basking and completely avoid sand-grass and clay banks. Habitat preference did not vary with size class.
3. Protected stretches of both rivers inside BNP (76 km) have resident gharial, intact habitats and few human threats. In contrast, the unprotected stretch of the Karnali (30 km) is threatened by boulder quarrying, sand mining and unlicensed fishing, and is avoided by gharials despite the availability of habitat.
4. This study established baseline data, including indices of population size, distribution and habitat preferences, and documented resident gharials that are breeding in the Babai River in BNP. The conservation of this Babai population is crucial for the species’ survival in BNP.
5. Based on this study, we recommend the following conservation actions on the Babai stretch: (a) determine hatching success; (b) assess juvenile recruitment; (c) consider supplementation by releasing captives; (d) study riverine features important as baselines; (e) accommodate upstream movements on the protected Babai stretch; and (f) protect the downstream Babai outside the boundary of the BNP.

     

Correlation studies on oil content and fatty acid profile of some Cruciferous species

Mean individual fatty acid concentration among differentspecies of the family Cruciferae are not similar because of the presence ofdifferent kind of significant relationship among the individual fatty acids.Brassica napus L., Sinapis alba L.,Raphanus caudatus L.f. Raphanus sativusL. and B. nigra (L.) Koch arecomparatively low erucic acid (<40%) containing species. Crambeabyssinica Hochst. ex. R. E. Fries collections gave as high as 60%erucic acid. Low erucic acid concentration was found associated with thepresence of high level of palmitic and oleic acid concentrations. Erucic acidconcentrations were found varied within the range of 42 to 57% among thecollections of Brassica rapa L. and B.carinata A. Braun. All the collections ofB. nigra (L.) Koch were found to havehigher proportion of linoleic acid than the corresponding oleic acidconcentration. Linolenic acid concentrations of B.nigra (L.) Koch was also higher in comparison to otherspecies of the Cruciferae. Raphanus collections were foundto contain higher levels of total saturated fatty acids as well as eicosenoicacid. Oil content of the total collections under present study did not show anysignificant relationship either with linolenic acid or with erucic acidconcentration. But significant positive relationship was observed between totaloil and erucic acid level within the collections of B.juncea Czern. & Coss. Similarly significant negativecorrelation was observed between total oil and linolenic acid content inBrassica rapa L. ssp. trilocularis (Roxb.) Hanelt, yellow sarson.     

Inactivation of seed-treatment fungicides by Rhizobium

2-Methoxyethylmercury chloride (MEMC) applied to cowpea seeds with Rhizobium provided little or no control of seedling rot caused by Rhizoctonia solani; similar treatment, but without Rhizobium, gave >40% control of disease. Treating seeds with quintozene and then with Rhizobium rendered the fungicide completely ineffective against R. solani infections; disease control was >70% when seeds were treated with quintozene only, and >60% when seeds were coated first with Rhizobium and then with quintozene; treatment with quintozene+Rhizobium gave about 25% control. Simultaneous treatment with Rhizobium considerably reduced the efficacy of captafol, chloroneb, carbendazim and thiophanate-methyl. Disease control by carboxin, benomyl and thiabendazole remained unaltered in the presence of Rhizobium, but only thiabendazole gave good control. Seeds treated with MEMC and Rhizobium produced seedlings without root nodules; nodulation was also decreased by captafol and by carboxin but six other fungicides had no effect. The implications of Rhizobium-fungicides interactions are discussed in the context of fungicidal control of root diseases.     

Interactive Effects of Elevated CO2 and Moisture Stress on the Photosynthesis, Water Relation and Growth of Brassica Species

Interactive effects of elevated CO2 and moisture stress on photosynthesis, growth and water relation of Brassica species were studied using open top chamber technology. Brassica species responded to the elevated CO2 significantly under moisture stress condition. The adverse effect of moisture stress on the photosynthesis and plant water components were minimized by elevated levels of CO2. Drought susceptible species of B. campestris and B. nigra responded better to elevated CO2 compared to drought tolerant Brassica species such as B. carinata and B. juncea. The plant water potential significantly improved by elevated CO2 coupled with higher stomatal resistance and root growth.     

Neutralizing and Complement-fixing Monoclonal Antibodies as an Aid to the Diagnosis of Equine Herpesvirus-1 Infection

One complement-fixing (C-MAb) and three complement-dependent neutralizing monoclonal antibodies (N-MAbs) were raised against Hisar-90-7 equine herpesvirus-1 (EHV-1) strain. The target antigen of the C-MAb (2A5) and two of the N-MAbs (1H6, 9C4) was identified as a 140 kDa polypeptide in Western blotting. The target antigen of N-MAb (9C6) could not be identified. Purified polypeptides of five EHV-1 strains isolated from different regions and at different times gave intense bands at 140 kDa when reacted with N-MAb (1H6) in Western blots. In sandwich ELISA, all four MAbs captured the viral antigen from clinical materials, giving a reliable and rapid diagnosis of EHV-1 infection in equines.     

Characterisation of peacock (Pavo cristatus) mitochondrial 12S rRNA sequence and its use in differentiation from closely related poultry species

1. Poaching of peacocks, the national bird of India, is illegal. People kill this beautiful pheasant bird for tail feathers and mix the meat with chicken or turkey. Differentiation of the meat of these species is essential in order to address the ambiguity about the origin of the sample. 2. The present study was carried out to investigate the use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of mitochondrial 12S rRNA gene for identification of these species. 3. Peacock mitochondrial 12S rRNA partial gene was amplified using universal primers, cloned and characterised. It was found to be 446 nucleotides long. 4. Sequence analysis revealed 86.8 and 84.1% similarity with reported turkey and chicken sequences, respectively. Sequence and phylogenetic analysis showed that the peacock is much closer to the turkey than the chicken. 5. PCR-RFLP of 446 bp amplicon using commonly available restriction enzymes AluI and Sau3AI produced a differential pattern for identifying these poultry species unambiguously.     

Herbicide resistant Phalaris minor in India—history of evolution,present status and its management

Phytoparasitica - The introduction and large scale cultivation of wheat cultivars which are semi-dwarf and high yielding in the north-western Indo-Gangetic Plains (IGPs) of India has led to the...     

Genetic characterization of guava (Psidium guajava L.) germplasm in the United States using microsatellite markers

Genetic diversity of 35 Psidium guajava L. accessions and three related species (P. guineense Sw., P. sartorianum (O. Berg) Nied. and P. friedrichsthalianum (O. Berg) Nied.) maintained at the U.S. Department of Agriculture (USDA), National Plants Germplasm System, Hilo, HI, was characterized using 20 simple sequence repeat (SSR) markers. Diversity analysis detected a total of 178 alleles ranging from 4 to 16 alleles per locus. The observed mean heterozygosity (0.2) and inbreeding coefficient (0.8) indicated a high level of inbreeding among the accessions tested. Multi-locus DNA fingerprints based on the 20 SSR loci unambiguously differentiated all accessions and revealed the absence of duplicated samples. Ordination and cluster analyses suggested that the genetic relationships between majorities of the accessions could be explained by geographic origin, mainly including tropical America, Southeast Asia and Hawaii. A Bayesian cluster analysis partitioned the accessions into two groups and the partition was largely compatible with the result of ordination analyses. Distance-based cluster analyses further indicated that accessions from same geographical region or breeding programs grouped together in spite of the inter-regional exchange of germplasm. Accessions from Southeast Asia were dominantly white fleshed, whereas accessions from tropical America and Hawaii exhibited diverse flesh colors. The results also indicated that accessions from the same region were likely derived from a small number of common ancestors or progenitors. All 20 SSRs were transferable to P. guineense, P. sartorianum and P. friedrichsthalianum, indicating a close relationship between the cultigens and wild relatives. Application of SSR markers in the USDA/Agricultural Research Service germplasm collection provides new insight into the diversity of the guava germplasm, which will be valuable in future breeding endeavors and the conservation of guava genetic resources.