Bikash Das

Evaluation of Major and Micronutrient Status of Acid Soils of Different Mango Orchards

The study involved distribution of nutrient elements in the acid soils of mango orchards. The objectives were to evaluate pH, organic carbon, and available macronutrient and diethylene triamine pentaacetic acid (DTPA)-micronutrient content in the soil profile. Depth wise (0–30, 30–60, 60–90, and 90–120 cm) soil samples were collected from 27 different mango orchards comprising of three health levels (unhealthy, medium, and healthy) and three age groups (1–3 years, 4–5 years, and 6–7 years). The pH of the surface soil was low and gradually increased with an increase in depth irrespective of health and age levels of the orchard. The pH was higher under the healthy orchard of 4–5 years old (6.00 at surface layer) and recorded 30% more compared to control (unhealthy orchard of 1–3 years old). The organic carbon was highest of 6.3 and 6.2 g kg−1 in A3H3 (healthy orchard of 6–7 years old) and A2H3 (healthy orchard of 4–5 years old), respectively, in the surface soil layer. The N content was higher under A1H3 (healthy orchard of 1–3 years old), A2H3, and A3H3 (142.2, 138, and 138 kg ha−1, respectively, in surface layer); whereas P and K were higher under A2H3 and A3H3 orchard (12 and 380.5 kg ha−1, respectively, in surface layer) than other orchards. The DTPA-extractable Fe and Mn contents were high status throughout the soil profile; whereas DTPA-extractable Zn and Cu were higher under A2H3 orchard (0.48 and 1.39 mg kg−1, respectively, in surface layer).

New report of Neozygites sp. infecting red spider mite Tetranychus urticae infesting French bean from Eastern Plateau and Hill region, India

An anamorphic entomopathogenic fungus Neozygites sp. belonging to the Family Neozygitaceae was found infecting the tetranychid mites Tetranychus urticae Koch (Acari: Tetranychidae) of French bean (Phaseolus vulgaris L.) for the first time in Eastern Plateau and Hill region of India in the month of October 2011. The report of entomopathogenic fungus could be of help in managing acaricide resistant mites.

New report of Hirsutella sp. infecting mango hopper Idioscopus clypealis from Chotanagpur Plateau, India

An entomopathogenic fungus belonging to the genus Hirsutella was found infecting the mango hopper, Idioscopus clypealis (Lethierry) (Hemiptera: Cicadellidae), for the first time in India in September 2011. The report of a natural control agent of mango hopper during the off season has special significance because its outbreak depends upon its residual hibernating population.

Assimilate Partitioning Behavior in Relation to Fruit Growth in ‘Shahi’ Litchi

Investigations were undertaken to develop a better understanding of assimilate partitioning behavior in litchi, with respect to the role of stored assimilates translocated from other sources in the plant during the fruiting season. The first experiment examined the fruit growth pattern in the litchi ‘Shahi’. The second experiment focused on the limitation of assimilate supply to litchi fruits by leaf removal and girdling. The third experiment was aimed at fulfilling the assimilate requirement of growing litchi bunches through current photosynthesis by foliar application of a photosynthesis enhancer (triacontanol). The fruits exhibited a sigmoidal growth pattern with a phase of rapid growth 40 to 60 days after fruit set. Irrespective of method or distance of source limitation, the maximum percent of fruit drop was observed when the source limitation treatments were imposed 30 days after fruit set. Source limitation at all the distances resulted in significant increases in percent of fruit drop over those with no source limitations. With respect to different treatments, all forms of source limitation resulted in significant increase in fruit drop over the control. The results suggest that a contribution of carbohydrate from current photosynthesis for partial fulfillment of total carbon demand of growing fruits is necessary. Only no limitation of current photosynthesis contributed towards 0% loss in fruit weight while a limitation of carbohydrate translocation (girdling) contributed towards an 8.5% loss in fruit weight. However, under the condition of limited carbohydrate translocation, restriction on current photosynthesis caused a 19.1% loss in average fruit weight. Studies on foliar application of photosynthesis enhancers (triacontanol) on fruit drop in litchi under restricted (girdled) and unrestricted translocation of assimilate from other parts of the plant were conducted. These indicated a reduction in the rate of fruit drop with an increase in the concentration of triacontanol in case of unrestricted translocation of assimilate. However, under restricted assimilate translocation, increasing concentrations of triacontanol did not result in reducing the percent of fruit drop. Hence, the study clearly indicated the major role of translocated assimilates from other plant parts in fulfilling the assimilate demand of growing fruits in litchi where current photosynthesis contributes partially towards assimilate demand.

Complete mitochondrial genome of Idioscopus nitidulus (Hemiptera: Cicadellidae)

Abstract The complete mitogenome of Idioscopus nitidulus (Cicadellidae) was sequenced. It comprises 15,287 base pairs (bp), including 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and a control region. The phylogenetic analyses based on concatenated thirteen protein-coding genes of mitogenomes recover the monophyly of Auchenorrhyncha (Fulgoromorpha + Cicadomorpha) and Sternorrhyncha as a sister group to Auchenorrhyncha. The complete mitogenome sequence of Idioscopus nitidulusis available in the GenBank with accession number: KR024406.

Genetic analysis of Bactrocera zonata (Diptera: Tephritidae) populations from India based on cox1 and nad1 gene sequences

Abstract The peach fruit fly, Bactrocera zonata, is among the most serious and polyphagous insect pest of fruit crops in many parts of the world under genus Bactrocera. In the present study, the genetic structure, diversity and demographic history of B. zonata in India were inferred from mitochondrial cytochrome oxidase 1 (cox1) and NADH dehydrogenase 1 (nad1) sequences. The efficiency of DNA barcodes for identification of B. zonata was also tested. Genetic diversity indices [number of haplotypes (H), haplotype diversity (Hd), nucleotide diversity (π) and average number of nucleotide differences (k)] of B. zonata populations across India maintain high level of genetic diversity without isolation by distance among the geographic regions. Non-significant negative correlation between pairwise Fst and geographic distance suggests a high level of gene flow among studied populations of B. zonata. The possibility of sudden expansion of B. zonata revealed through mismatch distribution analysis as well as negative Tajima’s D and Fu’s Fs values further supported by star-like network of haplotypes. DNA barcoding analysis suggests that B. zonata specimens can be clearly differentiated from other species with 100% accuracy of identification. Therefore, cytochrome oxidase 1 (cox1) barcode sequences generated in the present study could be a valuable source for the rapid identification and global population genetic study of B. zonata.

Predictive models for dry biomass and carbon stock estimation in Litchi chinensis under hot and dry sub-humid climate

ABSTRACT Accurate and reliable predictive models are necessary to estimate above and below ground biomass of plant and biomass carbon stock non-destructively. Different growth models namely viz, Linear, Allometric, Logistic, Gompertz, Richard’s, Negative exponential, Monomolecular, Mitcherlich and Weibull were fitted to the relationship between dry biomass of litchi tree components with collar diameter. Richard’s model outperformed the others and fulfilled the validation criterions to the best possible extent with lowest Akaike information criteria (AICc) of 90.47 and root mean square error (RMSE) of 1.79. The value of adjusted R2 ranged from 0.947 to 0.971 for the Richard’s models fitted on various biomass components and the ‘t’ values for all the components was found non-significant (p > 0.05) indicating the validation of the model. The estimated total dry biomass varied from 0.50 Mg ha−1 in two year to 5.71 Mg ha−1 in 10 year old litchi orchards. The estimated stored biomass carbon stock in litchi orchards (branches, bole and roots) varied from 0.10 Mg ha−1 in two year to 1.85 Mg ha−1 in 10 year orchards with CO2 sequestration potential from 0.19–4.63 Mg ha−1.

Standardization of grafting technique in litchi

The present experiment was conducted at the Research Centre, Ranchi of the ICAR Research Complex for Eastern Region, during the period from June, 2015 to December, 2016 to investigate the effect of girdling and defoliation of scion shoot on the success and growth of grafts in litchi cv. Shahi. The branches were girdled (removing of 3 mm ring from branches of 40–50 mm girth) one month before the collection of scion sticks for grafting. Defoliation was performed 7 days before the collection of scionsticks. Wedge grafting was performed under shadenet with temperature ranging from 26–32°C and RH 70–80%. The graft take success and vegetative growth were markedly improved as a result of girdling and defoliation. Among the different treatments, the minimum time required for bud sprout (15.40 days), highest scion height (24.25 cm), scion girth (7.14 mm), number of sprouts per graft (2.64), sprout length (4.80 cm), number of compound leaves (8.34), rachis length (9.33 cm), leaflet length (9.37 cm), leaflet width (3.37 cm) and graft success (56.43%) were observed in girdling + defoliation treatment. Scion which had higher girth after grafting was positively correlated with the number of compound leaves, leaflet length and leaflet width. The highest graft success rate (70.83%) was recorded during July. Hence, it was concluded that girdling of branches on scion varieties, one month prior to collection of scionstick and defoliation atleast 7 days before the collection, can enhance the success rate of grafting and plant growth of grafts in litchi.

Torrubiella pruinosa, a teliomorph of an entomopathogenic fungus Hirsutella versicolor of mango hopper (Idioscopus clypealis) from India

Torrubeilla pruinosa, a teliomorph of an anamorphic entomopathogenic fungus Hirsutella versicolor on mango hopper (Idioscopus clypealis) was observed. On the infected mango hopper, tiny pin head signs of ascomata were observed. Ascomata of T. pruinosa is pale brown or tawny brown, crowded, immersed in stroma, wall dark golden brown, 260–320 × 230–260 μm, asci clavate, hyaline and thin walled. The ascospores of T. pruinosa are fusiform, distoseptate with a faint tint of pigmentation, 17.5–25.0 × 5.0–7.5 μm. The anamorph stage of H. versicolor fungal hyphae is hyaline, septate and profusely branched, and conidiogenous (phialides) cells are hyaline, pear-shaped and smooth-walled with single or double sterigmata and rarely, multiple sterigmata. Each sterigmata bears single conidia which are hyaline, oval to pear-shaped.