Efficacy of pre- and post-emergence herbicide combinations on weed control in no-till mechanically transplanted rice

No-till mechanized-transplanted rice was evaluated for different combinations of pre- and post-emergence herbicides to determine feasible, economically viable weed management options to control complex weed flora in rice fields. All pre-emergence herbicides significantly reduced the population of grassy weeds; of these, pendimethalin resulted in the greatest reductions (83%) at 15 days after transplanting (DAT). Among five post-emergence herbicide treatments, the combination of bispyribac-sodium (10%SP) + pyrazosulfuron (10%WP) was found to be the most effective in controlling all weed flora at both 35 and 55 DAT. The sequential application of pendimethalin (pre-emergence) followed bispyribac-sodium + pyrazosulfuron (post-emergence) resulted in significantly higher rice grain yield (4.4 t-ha−1) and relative gross-margin (417 USD-ha−1) than all other treatments. A strong negative correlation was observed between rice grain yield and weed biomass, and a strong positive correlation between rice grain yield and weed control efficiency. Our findings demonstrate the potential to combine pre- and post-emergence herbicides in no-till mechanized-transplanted rice; these findings have applications globally in regions where rice is established by no-till or mechanized transplanting

Screening of Trichoderma isolates for their potential of biosorption of nickel and cadmium

Abstract Fourteen Trichoderma isolates were evaluated for their tolerance to two heavy metals, nickel and cadmium. Three isolates, MT-4, UBT-18, and IBT-I, showed high levels of nickel tolerance, whereas MT-4, UBT-18, and IBT-II showed better tolerance of cadmium than the other isolates. Under nickel stress, biomass production increased up to a Ni concentration of 60 ppm in all strains but then decreased as the concentrations of nickel were further increased. Among the nickel-tolerant isolates, UBT-18 produced significantly higher biomass upon exposure to nickel (up to 150 ppm); however, the minimum concentration of nickel required to inhibit 50% of growth (MIC50) was highest in IBT-I. Among the cadmium-tolerant isolates, IBT-II showed both maximum biomass production and a maximum MIC50 value in cadmium stress. As the biomass of the Trichoderma isolates increased, a higher percentage of nickel removal was observed up to a concentration of 40 ppm, followed by an increase in residual nickel and a decrease in biomass production at higher nickel concentrations in the medium. The increase in cadmium concentrations resulted in a decrease in biomass production and positively correlated with an increase in residual cadmium in the culture broth. Nickel and cadmium stress also influenced the sensitivity of the Trichoderma isolates to soil fungistasis. Isolates IBT-I and UBT-18 were most tolerant to fungistasis under nickel and cadmium stress, respectively

Hymenopteran parasitoid complex and fall armyworm: a case study in eastern India

Abstract Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) has significantly affected maize crop yields, production efficiency, and farmers’ incomes in the Indian Eastern Gangetic Plains region since it was first observed in India in 2018. A lack of awareness by maize growers of the appropriate selection, method, and timing of insecticide application not only creates a barrier to sustainable FAW control but also contributes to increased environmental pollution, reduced human health and increased production costs. We demonstrated that FAW inflicted the most damage in early whorl growth stage of maize, regardless of whether chemical insecticides were applied. FAW egg masses and larvae collected from maize fields in which no insecticides had been sprayed showed high parasitism rates by parasitoid wasps; in contrast fields that had been sprayed had much lower rates of parasitism on FAW. Ten hymenopteran parasitoids were observed in maize fields across the study region, suggesting a diversity of natural methods to suppress FAW in maize at different growth stages. These included two FAW egg parasitoids and eight FAW larval parasitoids. Microplitis manilae Ashmead was the most abundant FAW larval parasitoid species, and Telenomus cf. remus was the dominant FAW egg parasitoid species. Endemic FAW parasitoids such as those observed in this study have great potential as part of a sustainable, cost-effective agroecological management strategy, which can be integrated with other methods to achieve effective control of FAW

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Not AvailableIndigenous folk rice cultivars often possess remarkable but unrevealed potential in terms of nutritional attributes and biotic stress tolerance. The unique cooking qualities and blissful aroma of many of these landraces make it an attractive low-cost alternative to high priced Basmati rice. Sub-Himalayan Terai region is bestowed with great agrobiodiversity in traditional heirloom rice cultivars. In the present study, ninety-nine folk rice cultivars from these regions were collected, purified and characterized for morphological and yield traits. Based on traditional importance and presence of aroma, thirty-five genotypes were selected and analyzed for genetic diversity using micro-satellite marker system. The genotypes were found to be genetically distinct and of high nutritive value. The resistant starch content, amylose content, glycemic index and antioxidant potential of these genotypes represented wide variability and ‘Kataribhog’, ‘Sadanunia’, ‘Chakhao’ etc. were identified as promising genotypes in terms of different nutritional attributes. These cultivars were screened further for resistance against blast disease in field trials and cultivars like ‘Sadanunia’, ‘T4M-3-5’, ‘Chakhao Sampark’ were found to be highly resistant to the blast disease whereas ‘Kalonunia’, ‘Gobindabhog’, ‘Konkanijoha’ were found to be highly susceptible. Principal Component analysis divided the genotypes in distinct groups for nutritional potential and blast tolerance. The resistant and susceptible genotypes were screened for the presence of the blast resistant pi genes and association analysis was performed with disease tolerance. Finally, a logistic model based on phenotypic traits for prediction of the blast susceptibility of the genotypes is proposed with more than 80% accuracy.ICAR, Govt. of India under Niche area of Excellence (NAE) scheme with project reference number Edn.5(12)/2017-EP&H