Phenotypic and Genotypic screening of fifty-two rice (Oryza sativa L.) genotypes for desirable cultivars against blast disease.

Magnaporthe oryzae, the rice blast fungus, is one of the most dangerous rice pathogens, causing considerable crop losses around the world. In order to explore the rice blast-resistant sources, initially performed a large-scale screening of 277 rice accessions. In parallel with field evaluations, fifty-two rice accessions were genotyped for 25 major blast resistance genes utilizing functional/gene-based markers based on their reactivity against rice blast disease. According to the phenotypic examination, 29 (58%) and 22 (42%) entries were found to be highly resistant, 18 (36%) and 29 (57%) showed moderate resistance, and 05 (6%) and 01 (1%), respectively, were highly susceptible to leaf and neck blast. The genetic frequency of 25 major blast resistance genes ranged from 32 to 60%, with two genotypes having a maximum of 16 R-genes each. The 52 rice accessions were divided into two groups based on cluster and population structure analysis. The highly resistant and moderately resistant accessions are divided into different groups using the principal coordinate analysis. According to the analysis of molecular variance, the maximum diversity was found within the population, while the minimum diversity was found between the populations. Two markers (RM5647 and K39512), which correspond to the blast-resistant genes Pi36 and Pik, respectively, showed a significant association to the neck blast disease, whereas three markers (Pi2-i, Pita3, and k2167), which correspond to the blast-resistant genes Pi2, Pita/Pita2, and Pikm, respectively, showed a significant association to the leaf blast disease. The associated R-genes might be utilized in rice breeding programmes through marker-assisted breeding, and the identified resistant rice accessions could be used as prospective donors for the production of new resistant varieties in India and around the world.

Insect pest scenario in Uttarakhand Himalayas, India, under changing climatic conditions.

The Himalayan mountains are early indicators of climate change, wherein slight changes in climate can lead to a drastic variation in faunal diversity, distribution, invasion of fauna into higher altitudes, rapid population growth, shortening of life cycle and increased number of overwintering species. The insects best represent the faunal diversity. In recent years, due to variation in pattern of rainfall and temperature regimes, several insect pests have moved northwards and are posing great threat to hill agriculture. Few among them are greenhouse whiteflies, thrips and mites in protected cultivation system; blister beetles on flowers of cereals, pulses and oilseeds; invasive insect pests like fall armyworm of maize and tomato pin worm and sporadic pests like grasshoppers that are reaching a status of major key pest in various crops. Keeping in mind the phenomenon of climate change and associated changes in pest population, the present article focuses on emerging insect pest problems in cereals, millets, pulses, oilseeds and vegetables of Indian Himalayas, along with their changing population density with respect to different climatic parameters, the per cent increase in the pest damage over the years and their potential of gaining the status of major pests in near future and causing huge economic losses to hill agriculture.

Antioxidant activities and bioactive compound determination from caps and stipes of specialty medicinal mushrooms Calocybe indica and Pleurotus sajor-caju (higher Basidiomycetes) from India.

In this study, we evaluated total phenolics, condensed tannins, ascorbic acid, lycopene, ß-carotene, total antioxidant activity, reducing power, ferric-reducing antioxidant power, and radical scavenging activity (RSA) on ABTS and DPPH as well as metal chelating activity of methanolic and aqueous extract from caps and stipes of Calocybe indica and Pleurotus sajor-caju mushrooms. Per gram of extract, the different mushroom extracts contained 18.09-27.47 mg gallic acid equivalent of phenolics, 5.06-8.89 mg catechins of tannins, and 0.15-0.21 mg ascorbic acid. Principal component analysis (PCA) revealed that methanolic extract from caps of C. indica and P. sajor-caju contained higher ascorbic acid, total antioxidant activity, ß-carotene and radical scavenging activity (RSA) on 2,2-diphenyl-1-picrylhydrazyl (DPPH) than did the stipes. The aqueous extract from cap and stipe of P. sajor-caju had higher total phenolics and RSA on 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) as well as higher metal-chelating activity and ferric-reducing antioxidant power. The antioxidant potential is higher in the caps of P. sajor-caju and C. indica than in the stipes; the cap contributes most to antioxidant activity.