Uneven ripening in ‘Bangalore blue’ grape (Vitis vinifera × Vitis labrusca) berries in India is linked to seed viability

Uneven ripening (UR) is a physiological disorder of unknown origin in ‘Bangalore blue’ grape (Vitis vinifera × Vitis labrusca) leading to wine of inferior quality. A preliminary study found wide variations in total dehydrogenase activity (TDH) of seeds from unevenly ripe berries. In our experiments, gibberellin (GA₃) applied to young grapes increased seed TDH activity and reduced the incidence of uneven ripening to 2% compared with 35% in the control. In contrast, paclobutrazol (PBZ) decreased TDH activity and increased the incidence of the disorder to 58%. GA₃-treated berries had higher concentrations of sucrose and TDH activity in seed representing mature seeds with high viability. In contrast, PBZ-treated and control berries had higher concentrations of glucose and lower TDH activity, indicating immature seeds with low viability. These results suggested that competition among developing berries can lead to differences in seed gibberellin content, seed viability and the rate of berry growth resulting in green, purple, and black berries at harvest. The study established the role of seed viability in uneven ripening and demonstrated that the incidence of the disorder is reduced by the application of GA₃ to immature berries.     

Decoding attraction: Improving vine weevil monitoring by exploiting key sensory cues

BACKGROUND

Monitoring is an integral component of integrated pest management (IPM) programmes used to inform crop management decisions. Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), continues to cause economically significant losses in horticultural crops due to an inability to reliably detect the presence of this species before crop damage occurs. To improve vine weevil monitoring we investigated the behavioural responses of adult vine weevils to visual (monitoring tool shade/colour, height and diameter as well as the effect of monitoring tool and plant density) and olfactory (host plant and conspecifics) cues under glasshouse conditions.

RESULTS

Monitoring tool shade, height and diameter all influenced monitoring tool efficacy, with individuals exhibiting a preference for black, tall and wide monitoring tools. The total number of individuals recorded in monitoring tools increased with monitoring tool density. By contrast, plant density did not influence the number of individuals recorded in monitoring tools. Yew-baited monitoring tools retained a larger number of individuals compared to unbaited ones. Similarly, more vine weevils were recorded in monitoring tools baited with yew and conspecifics than in unbaited monitoring tools or those baited with only yew. Baiting monitoring tools with conspecifics alone did not enhance the number of vine weevils recorded in monitoring tools.

CONCLUSIONS

Our study confirms that visual and olfactory cues influence vine weevil behaviour. This provides information on key factors that influence vine weevil monitoring tool efficacy and can be used to inform the development of a new monitoring tool for this pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Production Characteristics and Size Variability of Channel Catfish Reared in Cages and Open Ponds1

Production characteristics of channel catfish (Ictalurus punctatus) reared in cages and open ponds were compared. Fish reared in open ponds had significantly better growth and food conversion ratios than fish reared in cages. Cages and open ponds stocked with fish which were closely graded in size produced fish with less size variability at harvest compared to ponds and cages stocked with nongraded and coarsely graded fish. The decrease in size variability at harvest was reflected in a greater proportion of marketable fish.     

The crocodile project in Papua New Guinea

Crocodilians throughout the world are under very heavy pressure from habitat destruction, human displacement and deliberate hunting for skins. In Papua New Guinea crocodiles of two species are still relatively plentiful and play an important part in the economy of many remote settlements. An attempt is being made by the national government to implement a policy intended to bring about the harvesting of wild crocodiles on a sustained yield basis and provide an economic incentive for conserving wild stocks in their natural habitat. Low human population density and the existence of vast swamplands make this a possibility. In recognition of the policy and the exceptional circumstances, Papua New Guinea has been exempted from trade restrictions imposed by a number of countries under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).     

Assessment of corneal thickness,intraocular pressure,optical corneal diameter,and axial globe dimensions in Miniature Horses

OBJECTIVE: To determine corneal thickness, intraocular pressure (IOP), and horizontal and vertical corneal diameter (HCD and VCD) and to obtain axial measurements of the anterior chamber depth (ACD), crystalline lens thickness (CLT), vitreous chamber depth (VtCD), and axial globe length (AGL) in eyes of Miniature Horses. ANIMALS: 41 healthy Miniature Horses. PROCEDURE: Ocular component measurements were obtained via ultrasonic pachymetry, applanation tonometry, ultrasound, and by use of a Jameson caliper. RESULTS: Mean IOP and corneal thickness for all eyes were 26.0 mm Hg and 785.6 microm, respectively. There was no correlation of age with IOP or corneal thickness and no difference in these variables between right and left eyes or between females and males. Mean HCD andVCD were 25.8 and 19.4 mm, respectively; although there were no differences between sexes or between right and left eyes, there was positive correlation of optical corneal diameters with increasing age. Mean ACD, CLT, VtCD, and AGL were smaller in Miniature Horses (5.6, 10.0, 18.1, and 33.7 mm, respectively), compared with values for full-sized horses; there was no difference in these variables between sexes or between right and left eyes in Miniature Horses, but they were correlated with increasing age. CONCLUSIONS AND CLINICAL RELEVANCE: In Miniature Horses, corneal thickness and IOP are similar to values reported for full-sized horses and do not increase with advancing age. Vertical corneal diameter, HCD, and AGL increase until 5, 7, and 2 years of age, respectively.     

Season of the year influences testosterone secretion in bulls administered luteinizing honrmone

The objective of the present study was to evaluate the secretion of testosterone (T) in bulls in response to the administration of varying doses of bovine LH (bLH) during the four seasons of the year. Five adult bulls (4 yr of age) were treated with an amount of bLH that was estimated to induce a 5 ng/mL amplitude pulse of LH in blood serum on five consecutive days around the spring equinox, summer solstice, fall equinox, and winter solstice. Five hours after this dose, bulls were treated with bLH in amounts that were estimated to induce a 0.25, 0.5, 1, 2, or 4 ng/mL amplitude LH pulse in blood serum in a Latin square design. Blood samples were collected for 5 h after administration of a dose of bLH that was estimated to induce the 5-ng amplitude LH pulse, and for 3 h after administration of the variable doses of bLH, and were then assayed for concentrations of T. Average concentrations and amplitude of T release after doses of bLH that were estimated to induce the 5-ng amplitude LH pulses were greater during the spring and summer than during the winter (P < 0.05). The area under the release curve (AUC) was greater during the spring than during the winter (P < 0.05). During the 3 h after treatment with the variable doses of bLH, T response was affected by dose (P < 0.001) and season (P < 0.001), but there was no dose x season interaction. Testosterone response increased in a dose-dependent fashion for all variables studied. The greatest average concentrations of T and AUC were observed in the spring compared with the fall and winter (P < 0.05). These data support our working hypothesis that testes of bulls are more responsive in releasing T in response to bLH stimulation in the spring and summer compared with the winter; however, there were no changes in sensitivity of the testes to LH during different seasons of the year as indicated by the lack of a dose of bLH x season interaction.