Management of Urd Bean Leaf Crinkle Virus in Urd Bean (Vigna Mungo L. Hepper)

Six plant extracts viz , Mirabtlis jalapa, Carthamus roseus. Datura metal, Bougainvitlea spectabilis, Boerhaavia diffusa and Azadirachta indica recorded maximum reduction in the incidence of urd bean leaf crinkle virus (ULCV) in urd bean crops at field level Among the antiphytovirat chemicals tested, DHT reduced the transmission to the maximum extent and increased the incubation period of virus in the urd bean plant Fresh buttermilk was significantly superior to fermented buttermilk in reducing the disease spread and increasing the incubation period of the virus in the plant. Casein was found effective in reducing the per cent transmission and increased the incubation period of the virus. Raising barrier crops viz maize, sorghum and pearl millet were equally effective in reducing the spread of the disease in field Spraying of DHT at two intervals. 7 and 22 DAS was found effective in reducing the disease spread when compared with Thuja, buttermilk, ivf jalapa and neem oil

Effect of environmental factors during seed development and maturation on seed quality in Sorghum bicolor (L.) Moench

Studies were conducted to evaluate the effect of environmental conditions on physiological characteristics of seeds of sorghum genotypes viz., CO 24, CO 25, CO 26 and JH 35 during seed development and maturation. In the present study, a steady decline in moisture content of the seed was observed. Length and width of seed increased rapidly between seven to 35 days after 50 per cent flowering. A steep increase in the dry weight of seed was registered between 14 and 35 days after 50 per cent flowering, beyond that the increase was gradual. Water absorption per cent declined from 16.5 to 12.0 per cent between 7 to 28 days and increasing steadily beyond 42 days (22.1 per cent) after 50 per cent flowering. The germination potential of seeds improved with seed development and maturity. The root length, shoot length, dry weight of seedling, field emergence, seed recovery, seed yield and vigour index were highest in seeds harvested at 35 and 42 days after 50 per cent flowering. Seed vigour as estimated through stress tests viz., soaking seeds in ammonium chloride and D-manitol and accelerating ageing and exhaustion tests revealed the superiority of seeds having maximum germinability, vigour and viability at 35 and 42 days after 50 per cent flowering. These stages respectively correspond to physiological and harvestable maturity

Studies on Seed Colouring in Soybean and Tomato

The effects of seed colouring using 25 dyes (i.e. 20 chemical and 5 natural dyes) on the quality of soyabean (cv. JS 335) and tomato (cv. Pusa Ruby) seeds were studied in the laboratory. Data were recorded for seed germination percentage, root and shoot length, whole seedling length, dry weight of seedling, vigour index, speed of germination and electrical conductivity. Rhodamine-B, Fast green and Malachite green for soyabean and Rhodamine-B and Fast green for tomato were the best dyes for seed colouring

Host plant resistance to grain mould in germplasm accessions of pearl millet (Pennisetum glaucum [L.] R. Br.)

The paucity of information on the moulds in Indian pearl millet (Pennisetum glaucum) led to the studies that were conducted at ICRISAT, India to evaluate (a) 447 germplasm accessions of 32 countries for mould reaction in rainy season, (b) threshed grain mould rating (TGMS) and mycoflora on grains of each accession, and (c) mould scores in field and in vitro. Post physiological maturity evaluation showed that 16% of the accessions secured a mould rating of 2. In TGMS, 18% were mould free and 57% secured a rating of 2 on a 1 – 9 scale. Assessment of twenty representative accessions in vitro against individual and mixed conidial suspensions (1610(6) conidia ml(71)) of Fusarium moniliforme, F. pallidoroseum and Curvularia pennisetti indicated significant correlation (r¼0.97) between the overall field and in vitro scores of mixed spores inoculations. The mycoflora for TGMS in blotter test revealed that Fusarium moniliforme, F. pallidoroseum, Curvularia pennisetti, Helminthosporium spp., Alternaria spp. and Colletotrichum spp. to be the major fungi affecting pearl millet grain. It is advisable to harvest panicles at the physiological maturity stage to obtain better quality grains. A strong negative correlation between TGMS and % GS (r¼0.4601) and positive correlation between TGMS and % UGS (r¼0.4654) indicated that, the lesser the threshed grain mould rating higher the % seed germination

Effect of temperature and humidity regimes on grain mold sporulation and seed quality in sorghum (Sorghum bicolor (L.) Moench)

Grain mold, induced by a number of non-specific fungi, causes substantial loss to seed/grain yield and quality in sorghum (Sorghum bicolor (L.) Moench). Fungal sporulation and grain mold severity are greatly influenced by temperature and relative humidity (RH) levels. We studied the effects of three incubation temperatures (25, 27 and 28°C) and two sets of RH levels (first set: 85, 90, 95, 98, and 100%, second set: 95, 96, 97, 98, 99 and 100%) on sporulation and grain mold severity in three major mold fungi (Curvularia lunata, Fusarium moniliforme, and Bipolaris australiensis) and on four each of resistant, moderately resistant and susceptible sorghum genotypes for sporulation and mold severity of major fungi. Results indicated that both fungal sporulation and grain mold severity increased on most sorghum genotypes with increasing incubation temperature from 25 - 28°C and RH levels from 95 - 98%. A linear relationship was observed among RH levels, grain mold severity and fungal sporulation. The highest sporulation of all the three fungi occurred at 28°C and 98% RH after 5 days of incubation. Among the three fungi, C. lunata grew and sporulated faster than B. australiensis and F. moniliforme, in that order. Among the sorghum genotypes, IS 25017 supported the least sporulation and had the lowest mold severity, followed by IS 8545 and PVK 801. Seed quality parameters, such as seed germination, seedling vigor index, field emergence potential, dehydrogenase and α-amylase activities declined significantly with increasing temperature and RH levels that supported heavy sporulation and grain colonization

Analysis of iron and zinc homeostasis in barnyard millet through transcriptome and ionome approach

Iron (Fe) and Zinc (Zn) are the most essential micronutrients needed for the growth and metabolism of higher plants. Fe and Zn has important role as a component of various enzymes that are involved in chlorophyll biosynthesis, photosynthesis and seed development. Plants have evolved with multifaceted Fe and Zn homeostatic mechanisms that regulate its acquisition from the environment and the movement between organelles, cells, tissues, and organs. In addition, Plant establishes a tightly controlled system including metal specific uptake transporters and transcriptional regulators to balance the uptake, utilization and storage of metal ions. Barnyard millet (Echinocloa frumentaceae), one of the minor millets is superior in Fe and Zn content compared to the most widely consumed cereals like rice and wheat. In the present study, ionomic profiling of grains of several barnyard millet accessions revealed that accession ACM-10-145 accumulates high Fe and Zn content (Fe: 14.5 mg/100g; Zn: 2.18 mg/100g). Furthermore, transcriptomic studies are in progress to understand the key factors involved in metal uptake and translocation in barnyard millet. The research outcome could be exploited for biofortification program in cereals

Studies on Seed Transmission of Urdbean Leaf Crinkle Virus on Vigna mungo

Seed transmission of Urdbean leaf crinkle virus was maximum in pods located at the base of the plant rather than pods produced subsequently. There was no relationship between extent of seed transmission and pod position on the plant while considering the individual plants showing infected leaves. The growing-on-test can be effectively ascertained for testing seed-borne infection. The virus was detected only in embryo and cotyledons. Seed lots showing 2.0 to 3.6 per cent seed borne infection recorded 45.2 to 86.5 per cent disease incidence in the post flowering stage in field conditions. The produce from this field yielded 3.6 to 8.6 per cent virus-infected seeds

Influence of plant age on infection and symptomatological studies on urd bean leaf crinkle virus in urd bean (vigna mungo)

Studies were conducted to identify the susceptible stage and symptomatology of urd bean leaf crinkle virus (ULCV) on urd bean. The incubation period was short and symtoms developed on second trifoliate leaf stage onwards when the plants were inculated at younger stage as compared to older plants. In the infected plants the increase in leaf size was evident from third trifoliate leaf stage onwards. Reduction in rachis length of terminal leaflet of infected trifoliate and thickening of stem and petiole were evident in infeceted plant. The size of stipules increased prior to the symptom development in lamina in all the infected plants These symptoms are of great use in eliminating infected plants in the early stages for effective management of the disease

Assessing the Single and Combined Toxicity of Chlorantraniliprole with Bacillus thuringiensis against Maize Fall Armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) under Laboratory Conditions

Use of synthetic insecticides for the management of fall armyworm (FAW) Spodoptera frugiperda (J. E. Smith) for a longer period will led to development of insecticide resistance. Identification of an eco-friendly synergistic agent to enhance the toxicity potential and reduced pesticide use as well become mandatory in due process. Hence the present study was formulated to find the single and combined toxicity of chlorantraniliprole and Bacillus thuringiensis (Bt) against the 2nd and 3rd larval instars of S. frugiperda. Single toxicity of chlorantraniliprole against 2nd and 3rd larval instars were 0.87 and 1.52 ppm (LC25); 4.08 and 6.50 ppm (LC50), respectively. With respect to Bt, single toxicity against 2nd and 3rd larval instars were 474.39 and 693.48 ppm (LC25); 1008.62 and 1228.62 ppm (LC50), respectively. Combination effect of chlorantraniliprole with Bt revealed that 2nd instar of FAW showed supplemental synergism at LC50 of chlorantraniliprole + LC25 of Bt. In the case of LC50 of chlorantraniliprole + LC50 of Bt, LC25 of chlorantraniliprole + LC50 of Bt and LC25 of chlorantraniliprole + LC50 of Bt combinations, they showed sub additive synergism. In 3rd instar larvae, the combined toxicity results were similar for all the combinations of chlorantraniliprole + Bt except LC25 of chlorantraniliprole + LC50 of Bt where it showed an antagonistic synergism. Activity of Carboxyl Esterase (CarE), Mixed Function Oxidase (MFO) and Glutathione-S-Transferase (GST) were found to be lesser in chlorantraniliprole LC50 + Bt LC25 combinations than single toxicity treatments. Therefore, combined use of chlorantraniliprole with Bt at LC50 of chlorantraniliprole + LC25 of Bt had supplemental synergism on fall armyworm under laboratory condition

Histopathological Studies on Urdbean, Vigna mungo Infected by Urdbean Leaf Crinkle Disease

The anatomical changes in stem, petiole and different leaves of urdbean leaf crinkle infected plant parts were highly conspicuous and were increase in number of layers and size of parenchyma cells and epidermal cells. The transverse section of infected stem of urdbean showed well developed cortex layer which was three times thicker than that of healthy leaf. The epidermal cells of infected tissue were significantly bigger than in healthy leaf. The number of vascular bundles increased in infected stem. The number of rows of xylem vessels and number of vessels per row were almost double in infected stem. The diameter of xylem vessels (metaxylem and protoxylem) increased significantly over healthy vessels. There was significant increase in number of layers of parenchyma cells and cambial cells and diameter of phloem parenchyma in diseased plant compared to healthy stem