Assessing the risk of mango quarantine pest Deanolis sublimbalis Snellen under different climate change scenarios

Journal of Plant Diseases and Protection - Considering the quarantine importance of the red-banded mango caterpillar, Deanolis sublimbalis (Crambidae: Lepidoptera), studies were carried out to...     

Role of sucrose synthase and invertases during petal senescence in rose (Rosa hybrida L.)

Summary

The roles of sucrose synthase and invertases were explored in relation to petal senescence in rose (Rosa hybrida L.). A developmental shift in the activities of these enzymes was observed. Higher sucrose synthase activity (0.52 – 0.95 µmol sucrose min^–1 mg^–1 protein) was observed during the initial stages (S1 and S2) of flower bud development, in contrast to invertases. However, the lower activity (0.56 µmol sucrose min^–1 mg^–1 protein) of sucrose synthase at a later stage (S6) of senescence could help the mobilisation of vacuolar sucrose. The different isoforms of invertase exhibited variable levels of activity. Insoluble acid invertases (IAI) were the most active (11.01 µmol glucose min^–1 mg^–1 protein), followed by soluble acid invertases (SAI; 8.02 µmol glucose min^–1 mg^–1 protein), and soluble neutral invertases (SNI; 0.74 µmol glucose min^–1 mg^–1 protein) at Stage-4. A significant decline in invertase activities (IAI, 0.98; SAI, 1.25; SNI, 0.32 µmol glucose min^–1 mg^–1 protein) coincided with higher levels of ethylene production at the later stages (S5 and S6) of flower bud development and senescence. We propose that developmental as well as ethylene-mediated pathways account for petal senescence in rose.     

Characterization of brown planthopper damage on rice crops through hyperspectral remote sensing under field conditions

Field experiments were conducted to characterize the brown planthopper (BPH) (Nilaparvata lugens (Stål.) damage stress on rice crops through hyperspectral remote sensing. The BPH-damaged rice crop had higher reflectance in visible (VIS) and lower reflectance in near-infrared regions (NIR) of the electromagnetic spectrum compared with uninfested plants. Mean reflectance of the rice crop varied among different BPH damage levels in various wavebands, with the greatest variation in NIR (740–925 nm). Correlations between plant reflectance and BPH damage depicted four sensitive wavelengths, at 764, 961, 1201 and 1664 nm in relation to BPH stress on the rice crop. Three new brown planthopper spectral indices (BPHI) were formulated by combining two or more of these sensitive wavelengths. Some of the hyperspectral indices reported in the literature were also tested for their suitability to detect BPH stress on rice crops. Based on crop reflectance corresponding to the sensitive wavelengths, a multiple-linear regression model was developed (R²=0.71, RMSE=1.74, P<0.0001) and validated (R²=0.73, RMSE?=?0.71, P<0.0001) that would help to monitor BPH stress on a rice crop and to issue forewarnings to growers.     

Management practices followed for draught cattle in the southern part of India

A study was conducted to determine the management practices followed by the farmers for draught cattle in Tamil Nadu state, India. Methods of procurement of animals, use of female animals, breeds preferred, housing, health, disposal of animals, feeding, shoeing, purchase of animal-drawn implements and their maintenance were all assessed with 210 farmers from seven districts across different agro-climatic zones in Tamil Nadu. The results revealed that 86 % of the respondents purchased the draught cattle from the livestock markets, most were bullocks but 20 small farmers and 5 medium farmers used female animals for ploughing. Among the indigenous breeds, Kangeyam (33 %) and Hallikar (30 %) breeds were the most popular for work. Most farmers (69 %) provided a mixed type of housing (provision of housing only during the night time and the rainy season) for their draught cattle. The major health problem reported by 63 % of respondents was pyrexia. Almost all farmers sold their animals at the age of 8–10 years. The feeding practices for draught cattle were poor especially with the small farmers. The cattle were fed with mainly paddy straw and rice bran. Oilcakes and cotton seeds were given to the animals which work throughout the year mainly for ploughing and carting. The draught cattle were first shod at around 2.5 years of age. The majority of the farmers (71 %) used the traditional animal-drawn implements made by local artisans, and the farmers were not aware of the new implements to reduce the drudgery of work cattle, designed by the Agricultural Machinery Research Centre and Agricultural Engineering Departments located in India.     

Soil test-based nutrient balancing improved crop productivity and rural livelihoods: case study from rainfed semi-arid tropics in Andhra Pradesh,India

Widespread multinutrient deficiencies in the semi-arid tropics (SAT) are among major factors for large gaps between farmers’ current crop yields and potential yields. In this study, we adopted a stratified soil sampling method to assess soil fertility-related constraints in farmers’ fields in eight districts of Andhra Pradesh in the semi-arid tropics of India. Most of the fields across all eight districts were critical in sulfur (61%–98% deficient fields); and up to six districts each in boron (83%–98% deficient fields), zinc (50–85% deficient fields), and soil organic carbon (55–97% deficient fields). Low soil organic carbon specifically indicates nitrogen deficiency. Phosphorus deficiency was critical in three districts (60–84%) while potassium in general was adequate. Soil test-based nutrient balancing through the application of sulfur, boron, and zinc in addition to farmers’ practice of adding only nitrogen, phosphorus, and potassium increased crop productivity by 8%–102%. Benefit–cost ratio (1.60–28.5) proved favourable to scale-up balanced nutrition. Better post-harvest soil health and residual benefits of sulfur, boron, and zinc up to four succeeding seasons indicated sustainability of the practice. Results showed that balanced nutrition is a way forward for sustainably improving farm productivity and livelihoods.     

Isolation and Culture of Ovine and Bubaline Small and Large Pre-antral Follicles: Effect of Cyclicity and Presence of a Dominant Follicle

Studies were conducted to examine the effects of the cyclicity and the presence of a dominant follicle (DF) in ovary on the recovery and in vitro growth of pre-antral follicles (PFs) in sheep and buffalo. Small pre-antral follicles (SPFs, 100–250 μm) and large pre-antral follicles (LPFs, 250–450 μm) were isolated from slaughterhouse ovaries in the breeding seasons by a mechanical and enzymatic method. The sheep and buffalo PFs were cultured in vitro for 6 and 15 days, respectively, and examined for their growth, survival and antrum formation rates and growth rates of oocytes in cultured pre-antral follicles. The follicles of the sheep and buffalo were recovered and cultured simultaneously within replicates. The recovery rates (number per ovary) of both SPFs and LPFs were significantly (p < 0.05) higher in cyclic ewes (SPFs: 22.0 ± 3.3 vs 12.1 ± 2.6 and LPFs: 16.0 ± 3.6 vs 9.2 ± 1.8) and buffaloes (SPFs: 9.2 ± 1.3 vs 4.1 ± 1.0 and LPFs: 10.3 ± 2.7 vs 5.4 ± 0.7) compared with those recovered from acyclic ones. Presence of a DF in ovary significantly (p < 0.05) reduced the recovery rates of LPFs in ewes (9.06 ± 2.7 vs 16.4 ± 3.8) but had no effect in buffalo. Cyclicity of animals or follicular dominance had no effects on in vitro growth, survival and antrum formation rates and growth rates of oocytes in cultured PFs of SPFs and LPFs in both sheep and buffalo. The in vitro growth, survival and antrum formation rates of LPFs and growth rates of oocytes in cultured LPFs were significantly (p < 0.05) higher than those observed in SPFs in both sheep and buffalo. The overall recovery and growth rates of the PFs were lower in buffaloes compared with ewes.     

Investigation of factors of probable significance in the pathogenesis of pneumonic pasteurellosis in cattle.

Six groups of ten beef calves six to eight months of age were shipped from western Canada and observed untreated for one week after arrival. The following parameters were measured daily: body temperature, plasma fibrinogen, nasal bacterial mean colony counts of Pasteurella hemolytica and Pasteurella multocida, total and differential leukoyte counts, packed cell volumes and the following, twice during the week: serum and nasal antibody titres to P. hemolytica and parainfluenza-3 virus. The lungs from 44 of the calves were obtained at post mortem and given a numerical score based on the degree of pneumonia present. Animals were designated SICK and WELL according to body temperature and plasma fibrinogen. The SICK animals had higher nasal mean colony counts of P. hemolytica than the WELL animals. The SICK animals had lower levels of serum antibody to P. hemolytica than the WELL on day 1 but had a greater rise in titre over the week than did the WELL animals. Both groups were similar with regard to serum antibody to parainfluenza-3 virus and there was little change in these titres. The SICK animals had a much greater degree of pneumonia than the WELL. The values of some of the parameters were combined with the data of previously studied animals in order to provide a comparison of SICK and WELL with larger numbers of animals.     

EST‐SSR analysis provides insights about genetic relatedness,population structure and gene flow in grass pea (Lathyrus sativus)

Grass pea (Lathyrus sativus) is an important food‐legume crop for resource‐poor farmers in the developing world. However, given its cultivation in the most underprivileged regions, the crop has not received appropriate scientific attention particularly from the genomic perspective, thereby giving it a status of genomic orphan. Nevertheless, some recent studies have attempted to develop modern molecular tools to strengthen the genetic and genomic research. In the present investigation, a comprehensive collection comprising 176 accessions was analysed using EST‐simple sequence repeats (SSRs). The SSR analysis revealed existence of a total of 51 alleles with an average polymorphic information content value of 0.35. A moderate level of gene diversity was noticed that ranged from 0.04 to 0.73 with an average of 0.43. Noticeably, two distinct subpopulations were recovered using cluster analysis. In addition, the presence of admixtures in population reflected the strong possibilities of gene flow between the accessions across the geographical boundary. In summary, we provide additional insights about the informativeness of available EST‐SSR markers along with an extended understanding of relatedness, genetic structure and gene flow in an under‐researched legume crop.     

Decomposition of carbon-14-labelled wheat straw in repeatedly fumigated and non-fumigated soils with different levels of heavy metal contamination

We analysed the decomposition of ¹⁴C-labelled straw at five different levels of heavy metal contamination (100-20,000 µg total Zn g^-1 soil) in non-fumigated and repeatedly fumigated soils. The soils were not spiked with Zn, but were taken from sites containing different heavy metal concentrations. Zn was only used as a reference and the effects observed are most likely due to this metal. Microbial biomass decreased with increasing heavy metal content of soils, paralleled generally by the decreasing amount of wheat straw ¹⁴C incorporated into the microbial biomass. In addition, the newly synthesised microbial biomass declined more rapidly as the incubation proceeded. In the repeatedly fumigated soils, microbial biomass ¹⁴C corresponded to roughly 50% of the maximum ¹⁴C incorporation of the non-fumigated soil. The relative decline during incubation was similar to that of the non-fumigated soil at the respective contamination level. These results reveal clearly that heavy metal effects on straw decomposition do not depend on the ratio of substrate C to microbial biomass C. In contrast to microbial biomass C, the mineralisation of the wheat straw was not seriously affected by heavy metal contamination. The same was true for all of the repeatedly fumigated treatments, where a much smaller microbial biomass mineralised nearly the same amount of straw as in the non-fumigated soils. However, repeated fumigation caused a strong reduction in the decomposition of soil organic matter. The ratio of CO₂-¹⁴C to microbial biomass ¹⁴C after 60 days was linearly related to the Zn concentration in both non-fumigated and repeatedly fumigated samples, clearly indicating that an additional energy cost is required by soil microorganisms with increasing heavy metal concentrations.