Pigeon pea is an important legume. Yield losses due to insect pests are enormous in the cultivation of this crop. Expression of cry proteins has led to increased resistance to pests in several crops. We report in this paper, expression of a chimeric cry1AcF (encoding cry1Ac and cry1F domains) gene in transgenic pigeon pea and its resistance towards Helicoverpa armigera. PCR, Southern hybridization, RT‐PCR and Western analysis confirmed stable integration and expression of the cry1AcF gene in pigeon pea transgenics. When screened for efficacy of the transformants for resistance against H. armigera, the transgenics showed not only high mortality of the larva but could also resist the damage caused by the larvae. Analysis for the stable integration, expression and efficacy of the transgenics resulted in the identification of four T3 plants arising from two T1 backgrounds as highly promising. The results demonstrate potentiality of the chimeric cry1AcF gene in developing H. armigera‐resistant pigeon pea.
Large number of primary transgenic events were generated in groundnut by an Agrobacterium mediated, in planta transformation method to assess the efficacy of cry1AcF against the Spodoptera litura. generation demonstrated homozygous nature. This clearly proved that though there is considerable improvement in average mean % larval mortality in T 2 generation, the cry1AcF gene was effective against S. litura only to some extent.
A rapid and efficient sap inoculation method for tobacco streak virus (TSV) was developed in sunflower. Sap from TSV-infected sunflower plants was freshly extracted in phosphate buffer and diluted serially from 10(-1) to 10(-8). Two-day old seedlings of sunflower were injured at the meristem and immersed in the sap for 10 min, maintained at 20 °C for 2-3 days and shifted to greenhouse. The surviving seedlings in the respective sap dilution were scored for symptoms of sunflower necrosis disease (SND). SND symptoms were seen in 80 % of the seedlings inoculated with a sap dilution of 10(-5). ELISA and RT-PCR analysis of coat protein and movement protein of TSV confirmed SND symptoms. The methodology was also found to be reproducible when the sap from the infected plants was inoculated onto healthy plants. The main aim of the study was to develop a primary screening strategy for the selection of transgenics developed for SND resistance. This methodology can also be extended for the analysis of resistance against other viruses.
A study was conducted to analyze the perception and pesticides usage practices by the small tomato growers in Ramanagara district of Karnataka using the pretested questionnaire and field observations. Detailed Information was obtained from 129 tomato growers wherein the information related to extent and types of pesticides used, knowledge about pesticides and their effectiveness was collected. Most of the respondents (98.44%) were male and most commonly farmers use 25 pesticides in tomato ecosystem. The major source of information for the small growers about the use of pesticides was the local pesticides dealers (55%) followed by Krishi Vigyan Kendra (33.3%). A good number of farmers (55%) used pesticides upon noticing the pest or disease incidence in tomato as curative measure. A great majority of the farmers (87.59%) used knapsack sprayers to apply pesticides. However, it is astonishing to observe that 83.72% of the growers used no or partial personal protection measures to spray the chemicals. Over 48% of the farmers expressed that they did not consider the wind direction (pesticide drift) during spraying due to which 87% of the farmers reported symptoms of pesticides poisoning after spraying. Most of the farmers (88.37%) enter into their farms within 48 hours after spraying while many farmers (83.72%) did not follow commonly recommended guidelines for safe use of pesticides including using personal protection measures. The study revealed that the tomato growers in the district are suffering since they are highly exposed to pesticides due to inadequate knowledge about safe and judicious use of pesticides. Education is essential to reduce pesticides application and encourage farmers to adopt integrated pest and diseases management practices along with safe use of pesticides through capacity building programmes.
K e y w o r d sTomato growers,
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