Slow Initial Growth Research Articles

Morphometric and energetic development of artificially reared giant kōkopu (Galaxias argenteus)

The larvae of some freshwater fish species of the Galaxiidae family are highly-prized in local cuisines in parts of the Southern Hemisphere, however, supplies from wild fisheries are limited. In New Zealand, the larval form of giant kōkopu, Galaxias argenteus, has long been held as a potentially viable aquaculture species due to its high market price (US$70–115 kg−1) and the limited supply of ‘whitebait’ from the wild fishery. However, little is known about the larval stages of this species and the current culture techniques result in poor growth performance and high mortality. This study describes aspects of the morphological development, and larval feeding requirements of giant kōkopu to assist in advancing their aquaculture. Morphometric characteristics of larval giant kōkopu that are critical to the success of larviculture were measured over the 77 day production period, from hatch to harvest. The initial slow growth of the larvae appears to be a result of rapid depletion of endogenous energy reserves prior to initiation of first feeding, while the extent of eye pigmentation and the presence of an open mouth upon hatching indicate that initiating feed provision should be brought forward from 3 DAH. Mouth gape width at hatch was 348 μm and increased rapidly in the first four weeks to 651 μm suggesting that larger live feed items could be used as the initial feed, such as instar-II Artemia. At harvest, the larvae varied enormously in size and condition, with larger fish showing early signs of metamorphosis, such as increasing opacity of flesh and coloration of internal organs. The extent of this variability reduces productivity, increases waste and results in a lower quality product. The results confirm that an improved understanding of the developmental biology of the larvae can assist in providing a more effective feeding regime, particularly for determining the timing of first feed provision and the feed particle size requirements throughout larval development. Consequently, heterogenous growth performance is an aspect of production that needs further attention for developing the efficient aquaculture production of this species.

Bioefficacy of Imazethapyr Applied Alone and in Combination with other Herbicides in Black Gram and their Residual Effect on Succeeding Pearl-millet and Sorghum Crops

Background: Weeds are one of the major constraints in achieving yield potential of black gram. Due to slow initial growth of black gram, weeds compete effectively and caused reduction in growth as well as yield of black gram. Hand weeding is neither practicable nor economical due to unpredictability of weather and high labour cost, respectively. Therefore, application of herbicides is considered as the best approach for efficient weed control in black gram. Methods: A field experiment was conducted at Research Farm of Department of Agronomy, CCSHAU, Hisar during summer and kharif 2017 to evaluate the effect of different weed control treatments in black gram and their residual effect on succeeding pearl millet and sorghum crops. Total of fourteen weed control treatments were replicated thrice in randomized complete block design (RCBD).Result: Dactyloctenium aegyptium (37%), Trianthema portulacastrum (34%), Cyperus rotundus (21%) and Digera arvensis (8%) were the major weed flora associated with black gram at 30 DAS. Both at 30 and 60 DAS, PE application of imazethapyr + pendimethalin (RM) at 1000 g ha-1 provided 100% control of D. aegyptium and T. portulacastrum. PE application of imazethapyr + pendimethalin (RM) at 1000 g ha-1 was the most significant herbicide treatment (90% control of weeds) at 30 DAS however, 3-4 leaf stage application of imazethapyr + imazamox at 70 g/ha recorded with highest control of weeds (89%) at 60 DAS. Maximum seed yield (912 kg ha-1) and yield attributes of black gram were obtained in weed free treatment which was statistically at par with two hoeing performed at 20 and 40 DAS (895 kg ha-1) and PE application of imazethapyr + pendimethalin (RM) at 1000 g ha-1 (878 kg ha-1). Imazethapyr and its RM combination with imazamox applied at 3-4 leaf stage had phytotoxic effects on black gram at 30 DAS which suppressed the growth and caused yield penalty. Residual effect or phytotoxicity was not observed on succeeding pearl millet and sorghum crops.

Radiation interception and radiation use efficiency in mixtures of winter cover crops

Abstract Context Cover crops are sown in autumn after harvest of a main crop to capture residual nitrogen and to build biomass that will contribute to soil organic matter after being ploughed under. Mixtures are purportedly more productive than pure stands of single species. Research problem Dry matter accumulation in field crops can be separated in the processes of resource capture and resource conversion. Here we apply this conceptual approach to analyse whether and how pure stands of single species and stands of species mixtures differ in radiation capture and radiation use efficiency. Methods cover crops were sown as pure stands (12 treatments) or mixtures (11 treatments) at two years in four sites, three in the Netherlands and one in northern Germany. Ground cover was measured throughout a growing period of up to twelve weeks to quantify radiation capture while final biomass was determined at harvest. The ratio of biomass and cumulative radiation capture was used to calculate radiation use efficiency. Results Oats and crucifers were the most productive species. Crucifers covered the soil quickly and their radiation capture was consequently high (517 MJ m−2) but their radiation use efficiency was low (0.80 g MJ-1). Oats intercepted less radiation (459 MJ m−2) than crucifers but had a higher radiation use efficiency (1.15 g MJ-1). Legumes had low radiation interception (332 MJ m−2) combined with low radiation use efficiency (0.64 MJ m−2) while the group of forb species belonging to other plant families (e.g. Linaceae, Boraginaceae and Asteraceae) had intermediate radiation capture (371 MJ m−2) and radiation use efficiency (0.84 g MJ-1). The radiation capture and radiation use efficiency of mixtures was similar to that of the dominant species in the mixtures, in all cases a crucifer or oats. Conclusions and implications The analysis of radiation capture and radiation use efficiency in this study indicates that mixture performance was governed by species dominance within the mixture, with the species capturing most of the light determining to a large extent the radiation use efficiency of the mixture as a whole. Results show the importance of including one or more productive species in a species mixture used for cover cropping, i.e. oats or a crucifer. If species with slow initial growth or low radiation use efficiency are included in a mixture to provide particular services, such as flower resources, atmospheric nitrogen fixation or antibiosis against pests, these species should be included in a large enough proportion to enable their establishment in the mixture.

Review: Winged bean (Psophocarpus tetragonolobus) cropping systems

Abstract. Eagleton GE. 2020. Review: Winged bean (Psophocarpus tetragonolobus) cropping systems. Biodiversitas 21: 5927-5946. Winged bean (Psophocarpus tetragonolobus (L.) DC.) is a rambling, nitrogen-rich, leguminous crop of the Old-World tropics. This review of winged bean (WB) within cropping systems of Southeast Asia and Melanesia revisited four traditional roles that the crop has played: as a minor courtyard vegetable of villages and suburbs throughout the region; as a popular tuber crop in the irrigated plains of Tada-U township in Central Myanmar; as a companion crop in the mixed garden fields of Wamena in Indonesian New Guinea; and as a niche tuber crop in rotation with sweet potato near Goroka in Papua New Guinea (PNG). Drawing upon such traditions, researchers since the 1970s have identified potential new roles for winged bean. In Malaysia, vegetable pod yields up to 35 t ha-1 over a 25-week growing period have been obtained from solidly trellised, branching cultivars. Ratooning the crop through a further two cycles covers the cost of the trellising. Tubers from un-trellised field crops in Myanmar, and of staked, pruned garden crops in highland PNG have been estimated to produce crude protein yields of at least 300 kg ha-1 and 600 kg ha-1, respectively. Synergies between the gene-pools and cultural traditions would be expected to expand the range, raise the yield and stabilize the quality of tuber crop production. Researchers in Sri Lanka intercropped maize with winged bean. At optimal plant densities, they recorded a corn cob yield of 5 t ha-1 together with a cumulative winged bean fresh pod yield of 27 t ha-1. In Kentucky (380N), the combination of maize with winged bean to produce silage resulted in 11-18% greater biomass with 39-67% greater nitrogen per hectare than maize monocrop control plots. Branching winged bean cultivars have significant potential for benign, high-nitrogen cover and forage crops. Promiscuous nodulation and the development of storage root-systems compensate for slow initial top growth which then accelerates to produce a substantial yield of highly digestible leaf protein and vitamins. Hard-seededness and daylength-sensitive phenology are significant, surmountable, barriers to an expanded role for winged beans.

Localized dynamics following a quantum quench in a non-integrable system: an example on the sawtooth ladder

Motivated by the recent discovery of ergodicity breaking in geometrically frustrated systems, we study the quench dynamics of interacting hardcore bosons on a sawtooth ladder. We identify a set of initial states for which this system exhibits characteristic signatures of localization like initial state memory retention and slow growth of entanglement entropy for a wide parameter regime. Remarkably, this localization persists even when the many-body spectrum is thermalizing. We argue that the localized dynamics originates from an interaction induced quantum interference. Our results show that the sawtooth ladder can be a fertile platform for realizing non-equilibrium quantum states of matter.

A review on integrated approach for the management of weeds in Cowpea (Vigna unguiculata)

Cowpea (Vigna unguiculata) is the most important leguminous crop raised as pulse as well as a vegetable crop in India. The slow initial growth and wider spacing necessitate weed control in the early stages of crop growth. The critical period of crop weed competition in cowpea was 20 to 30 DAS. Season-long crop weed competition resulted in a yield reduction of 40 to 90 per cent in cowpea depending on the intensity of weed infestation, weed flora, season, location, and the climatic condition prevailed. Mulching, manual weeding and stale seedbed are the different cultural methods which can be adopted for weed control in cowpea. Chemical method of weed control is the cheapest and economically viable option for weed control in cowpea. Both Pre-emergence herbicides viz., pendimethalin, diclosulam and imazethapyr and post-emergence herbicides viz., imazethapyr, quizalofop-p-ethyl can be used for weed control in cowpea. Studies revealed that pre-emergence application of herbicide (imazethapyr/pendimethalin or diclosulam) followed by manual weeding or post-emergence application of herbicides (quizalofop-p-ethyl or imazethapyr) or mulching followed by post-emergence application of herbicides (quizalofop-p-ethyl or imazethapyr) were found to be more effective for the broad-spectrum weed control in cowpea. The integrated approach of weed control has resulted in a higher yield, net returns and B: C ratio in cowpea.

Weed Management in Pulses: A Review

Pulses are the important crop after cereals and is the cheapest source of dietary protein. After the Green revolution, the production of pulses in India remain stagnant over the years due to various biotic and abiotic stresses. Among the various biotic stresses, weeds are the major one which causes severe yield loss in pulses. Due to initial slow growth of pulses, weeds emerge first and gain competitive advantage over the crop and exhibit smothering effect on crop. Moreover, major area of pulses (84 per cent) are under rainfed condition and grown in combination with non-legume crop. As a result, pulses are subjected to various types of biotic and abiotic stresses. Weeds besides causing direct loss in yield also hinder farm activities and serve as alternate host to many pests. Weed management in pulses is essential to bring the weeds below the threshold level to maximize the seed yield and quality. The literature regarding the importance of weed management in pulses, weed flora, critical period of crop weed competition and different weed management methods of weed control are collected and presented in this paper.Weeds are the predominant biological constraint in pulse production due to the slow initial growth of the crop. Strategies’ of weed management depends on the weed competition, types of weeds present and weed control method adopted. In general, critical period of weed competition for short duration pulses is up to 30 days and for long duration pulse crops it is up to 60 days. The major three types of weeds viz., grasses, broad leaved weeds and sedges were found in association with pulses. Intensity of weed infestation varies with agroecological conditions and crop management practices followed. A system approach is necessary to maintain the weed population below the economic threshold level thereby reducing the yield loss. Integrated weed management (IWM) which has been proved to be more effective than any single method in alleviating the buildup of weeds in pulse crop.

Review of research on INM and various weed control practices in rice (Oryza sativa L.)-Groundnut (Arachis hypogaea L.) cropping system under irrigated medium land situation

Rice-groundnut cropping system is one of the important cropping systems of India. Rice (Oryza sativa L.) is the staple food of the world. Rice is a heavy nitrogen feeder, but fertilizer nitrogen use-efficiency is very low under tropical conditions. Nutrient management provides an approach for feeding the plants with nutrients as and when required. It is therefore, necessary to apply fertilizer elements particularly N, P and K in optimal quantity to increase and sustain the productivity. A major portion of nitrogen in wetland soils occurs in organic pool, though this is usually low. Complementary use of organic and biological source of plant nutrient along with chemical fertilizer is of great importance for the maintenance of soil health and productivity. Sustainable cropping systems require crop yields should be stable through the maintenance of soil fertility and the balance of nutrients in the system. Increases in soil carbon levels require sustained periods of balanced fertilization and residue retention. Weed infestation in rice remains the largest constraint, limiting its productivity. Groundnut (Arachis hypogaea L.) is one of the most important edible oilseed crop extensively cultivated in the world. This groundnut is highly susceptible to weed infestation because of its initial slow growth habit up to 40 days after sowing, short plant height and underground pod bearing habit. In this review studies on the effect of integrated nutrient management and weed control practices on rice (Oryza sativa L.) – groundnut (Arachis hypogaea L.) cropping system are discussed. Judicious application of chemical fertiliser coupled with green manuring of Dhaincha and use of herbicides in rice as well as succeeding groundnut crop for management of weeds increases the productivity of the system.

Production Potential and Economic Feasibility of Planting Pattern and Nutrient Management in Pigeonpea (Cajanus cajan) Based Intercropping System under Rainfed Condition

Background: Pigeonpea grown as sole crop is not economically viable because of its slow initial growth rate, low productivity and longer duration. The initial slow growth rate, widely spaced, deep root system and longer duration of pigeonpea offers a good scope for intercropping with fast growing and early maturing compatible crops. Proper row arrangement of main as well as intercrops in appropriate proportion is the promising way to exploit the natural resources such as space, nutrient, sunlight, soil moisture to greater extent and boost up the system productivity.Methods: The study was carried out for four consecutive years during kharif 2013-14 to 2016-17 at Tirhut College of Agriculture, Dholi, RPCAU, Pusa, Bihar. The treatment comprised 3 intercropping systems with two method of planting viz, pigeonpea (60 cm)+ urdbean (1:1), pigeonpea (60 cm) + sesame (1:1), pigeonpea (60 cm) + sorghum (1:1), pigeonpea paired (45 cm) + urdbean (2:2), pigeonpea paired (45 cm) + sesame (2:2), pigeonpea paired (45 cm) + sorghum (2:2) and 3 fertilizer levels of intercrop viz, 75% recommended dose of fertilizer (RDF), 100% RDF and 125% RDF along with sole crop of pigeonpea, urdbean, sesame and sorghum. Result: Intercropping of urd bean [Vignamungo (L.) Hepper], sesame (sesamumindicum (L.) and sorghum (sorghum bicolor (L.) Moench] paired row planting of pigeonpea (45 cm) in 2:2 row ratio recorded significantly higher pigeonpea – equivalent yield, LER, water-use efficiency, production efficiency and net return than their intercropping with pigeonpea in normal planting pattern (60 cm) in 1:1 row ratio and sole pigeonpea. However, only pigeonpea + urdbean and pigeonpea + sesame in paired row planting recorded significantly higher B:C ratio than sole pigeonpea. Pigeonpea + urdbean in paired row planting recorded significantly higher pigeonpea equivalent yield (3.57 t/ha), LER (1.81), water-use efficiency (4.96 kg ha/mm), production efficiency (12.01 kg/ha/day), NPK-uptake by pigeonpea, net return (148.63 x 103 ¹ /ha) and B:C ratio (4.84) than their intercropping in normal planting pattern, pigeonpea + sesame and pigeonpea + sorghum in both planting pattern. Pigeonpea + urdbean and pigeonpea + sesame in paired row recorded significantly higher number and dry weight of nodules/plant than sole pigeonpea. Pigeonpea equivalent yield in pigeonpea + urdbean intercropping system did not increased significantly with increasing levels of fertilizer. However, it increased significantly upto RDF and 125% RDF of sesame and sorghum in pigeonpea + sesame and pigeonpea + sorghum intercropping systems respectively in both the planting pattern. Pigeonpea + urdbean in both the planting pattern reduced bulk density of the soil and increased organic carbon, available N,P,K content of the soil than other intercropping systems and initial soil value but magnitude of improvement in physico-chemical properties of soil was higher in paired row planting.

The effect of supplementary ultraviolet wavelengths on the performance of broiler chickens

Qualities of the light environment, such as the spectral composition of light, have been shown to impact growth and performance of broiler chickens. UVA light is visible to broiler chickens, whereas UVB wavelengths promote endogenous vitamin D synthesis, which could support their rapid development. The aim of the current study was to investigate the impacts of supplementary UVA and UVB wavelengths on performance indicators of broiler chickens.Day-old Ross 308 chicks (n = 638), reared to a target stocking density of 33 kg/m2, were randomly assigned to 1 of 3 lighting treatments: A) White light emitting diode (LED) and supplementary UVA LED lighting (18-h photoperiod); B) White LED with supplementary UVA and UVB fluorescent lighting providing 30 μW/cm2 UVB at bird level (lights on for 8 h of the total photoperiod to avoid overexposure of UVB); and C) White LED control group, representative of farm conditions (18-h photoperiod).Mortality was recorded, and broiler chickens were individually weighed at 8, 15, 22, 27, and 34 D of age. Generalized linear models and nonlinear mixed effects models (Gompertz curve) were fitted to determine the effects of UV wavelengths on broiler mortality and growth performance.UV did not impact breast or leg weight of broiler chickens but was associated with differences in mortality, growth, and end weight. Broiler chickens provided with UVA for the full 18-h photoperiod had slower initial growth than control broilers and a reduction in mortality. Results from male broilers reared with supplementary UVA + UVB for 8 h indicated they could reach finishing weights sooner than controls, which supports the potential for UVA + B to improve the growth performance of males.Results suggest that the provision of supplementary UVA + UVB wavelengths may improve the performance of male broiler chickens. The reduction in mortality in the UVA only treatment may warrant further investigation. The inclusion of UV wavelengths within poultry lighting regimes represents a promising area of further study.

CONTROL OF WEEDS IN THE JAPANESE PUMPKIN HYBRIDS

The Japanese pumpkin known as "Tetsukabuto" is the result of crossing selected lines of squash. Squashes are highly susceptible to weed interference due to slow initial growth, requiring more considerable attention as to their control. Studies focusing on the losses caused by weeds to Japanese pumpkin hybrids are scarce. Thus, this study aimed to evaluate the influence of weed control on the fruit yield of Japanese pumpkin hybrid cultivars. A randomized block design with four replications in a 3x4 factorial scheme was used. Three cultivars (Corina F1, Triunfo F1, and Takayama F1) and four weed control periods, without weed control, weed control from 0 to 30 and from 0 to 60 days after transplanting (DAT), and weed control throughout the crop cycle (continuous control) were evaluated. The harvest was carried out at 105 DAT, and it was evaluated population density of the weed community, yield, fruit diameter, fruit fresh mass, number of fruits per plant, pulp thickness, and internal fruit cavity thickness. The weed control from 0 to 60 DAT and continuous weed control resulted in the lowest weed population density and weed dry matter. The weed control from 0 to 60 DAT provided a higher number of fruits per plant, fruit diameter, fruit fresh mass, and thicker pulp. The highest development and fruit yield of Japanese pumpkin hybrids was observed when the plants were free from weed interference until 60 days after transplanting.

Allelopathic intercrops and its mulch as an integrated weed management strategy for rainfed Bt-transgenic cotton hybrids

Weed management in cotton is a major challenge because of the slow initial crop growth. Further, noxious weeds (purple nutsedge: Cyperus rotundus L.) and invasive weeds (smooth joyweed: Alternanthera paronychioides A. St.-Hil.) are difficult to control. Thus, the small and poor farmers of the Indian sub-continent are in need of effective integrated weed management strategies. Intercropping in the wide row space Bt-transgenic cotton hybrids is a possible option to the readily available expensive technologies such as herbicides and polythene mulch. We evaluated 12 different intercrops and its mulching, over 5-years (2014–15 to 2018–19), on weed control, species diversity, seedcotton yield and economics. Intercrops were compared with newspaper or polythene mulch, farmers’ practice (FP) and a control. Number of monocot and dicot weeds were the least in the polythene mulched plots and the greatest in the control treatment. Intercrops significantly reduced weed density by 43–71% compared to the control treatment. Intercrops varied in their weed suppression over years, with a consistent weed suppression observed in the sunnhemp plots. Weed biomass was, on an average, reduced by 43% in the sunnhemp plots compared to the FP. High total phenolics and terpenoid content in the above ground parts of sunnhemp possibly contributed to the inhibition of weed seed germination and growth. The top five weeds, in the study area, were Echinochloa colona L., C. rotundus, Urochloa plantaginea (Link.) Hitch., Corchorus trilocularis L. and A. paronychioides. Polythene mulched plots had the highest seedcotton yield but net benefits were the most with sunnhemp intercrop (USD 295.2 ha-1 vs. 176.2 ha-1 for the polythene and 67.2 ha-1 for newspaper mulch) due to reduced input costs. Sunnhemp grown as an intercrop and later mulched can be used as a tool to filter out noxious weeds and provide an effective strategy for integrated weed management.

Enhancing productivity of sugarcane by successful weed management through integration of brown manuring of Sesbania and pre and post emergence herbicides

Field experiments were conducted to evaluate the combined effect of brown manuring with post emergence herbicide on weed management in planted sugarcane. Weeds are one of the major biotic stress and its management was the very costliest agronomic input in the successful crop production. Weeds can cause yield reduction in sugarcane up to 40%. Indiscriminate use of herbicides can accelerate weed flora shift and resistance besides causing environmental pollution and non-target toxicities and. Brown manuring is a no till version of green manuring using a post emergence herbicide. For brown manuring, Sesbania is grown as intercrop with sugarcane for initial 35 days, and then, is knocked down by 2,4-D. BM had multiple benefits including weed management. In Sugarcane its wider inter row space and its initial slow growth would allow to formulate an integrated weed management (IWM) module with brown manuring and herbicide. Therefore, this experiment was undertaken at Agricultural Collage and Research Institute, Madurai during 2016 to 2018 to evaluate the integrated effect of brown manure and herbicide on weed management in sugarcane. Among nine treatments, three were BM of sesbania and three were in- situ incorporation of sesbania, involving one intercultural operation at 90 DAP (Hand hoeing; Metribuzin: halosulfuron application). In addition, three controls, namely atrazine 1 kg /ha + power weeeding at 45 & 75 DAP, hand weeding twice and unweeded control were also adopted and the experiment was laid out in a randomized block design with three replications. A pre-emergence application of pendimethalin 2.0 kg/ha was made in all sesbaniarasied treatments. The results showed that application of pendimethalin 2.0 kg ha-1 + Sesbania (brown manuring) + hand hoeing at 90 DAP recorded minimum number of weeds and weed dry weight. The higher weed control efficiency (78.96%), cane yield (100.5 t /ha) and benefit cost ratio (2.72) were found with PE application of Pendimethalin + Sesbania(Brown manuring) + hand hoeing at 90 DAP compared to POE herbicides and insitu incorporation of Sesbania.

Ion Beam Analyses of Moisture Reaction for Single Crystal Lithium Deuteride

ABSTRACTIon beam analyses were completed on single crystal LiD (lithium hydride with deuterium on the hydrogen sites) to determine products of hydrolysis with decarbonated H2O (with protium-hydrogen) in an inert gas. Rutherford backscattering spectrometry showed movement of oxygen into the bulk of LiD samples. Hydrolysis rates for the single crystal LiD showed relatively slow initial growth of an oxygen-containing layer. Final growth rates varied widely with H2O level, from 1010 to 1015 (atoms/cm2)/min. at 5.6 and 28 mmol/min. H2O respectively. Simulations of spectra show the hydrolysis product to be LiOH. Elastic recoil detection identifies the hydrogen in the hydroxide layer upon dosing with H2O (with natural, protiated hydrogen) as primarily protium. Micrographs showed island growth occurring initially, with convergence to a full-coverage hydrolysis layer.

Efficacy of Voriconazole against Aspergillus fumigatus Infection Depends on Host Immune Function.

Antifungal therapy can fail in a remarkable number of patients with invasive fungal disease, resulting in significant morbidity worldwide. A major contributor to this failure is that while these drugs have high potency in vitro, we do not fully understand how they work inside infected hosts. Here, we used a transparent larval zebrafish model of Aspergillus fumigatus infection amenable to real-time imaging of invasive disease as an in vivo intermediate vertebrate model to investigate the efficacy and mechanism of the antifungal drug voriconazole. We found that the ability of voriconazole to protect against A. fumigatus infection depends on host innate immune cells and, specifically, on the presence of macrophages. While voriconazole inhibits fungal spore germination and growth in vitro, it does not do so in larval zebrafish. Instead, live imaging of whole, intact larvae over a multiday course of infection revealed that macrophages slow down initial fungal growth, allowing voriconazole time to target and kill A. fumigatus hyphae postgermination. These findings shed light on how antifungal drugs such as voriconazole may synergize with the immune response in living hosts.

Geographic variation in life-history traits of the long-lived monacanthid Meuschenia scaber (Monacanthidae)

Demography and life-history characteristics of reef fishes may vary as a consequence of ecological and environmental factors that lead to changes among populations. We evaluated variation in life-history traits in the leatherjacket Meuschenia scaber (Monacanthidae) through age-based analysis of 2112 fish collected from three locations in New Zealand distributed along an 8° latitudinal and 5 °C SST gradients. Meuschenia scaber showed distinct differences in age structure, growth patterns, maximum size and age, sex ratio and mortality across this latitudinal gradient. At warmer lower latitudes (Hauraki Gulf) the population displayed significantly greater mean adult body size (Lmax) and asymptotic length (L∞) in comparison with the other two locations. Fish from Tasman Bay (mid-range latitude) had a longer life span (Tmax) and a maximum age of 19 years, which represents the longest-lived monacanthid documented to date. Fish from Pegasus Bay (cooler higher latitude) showed a slower initial growth than lower latitude counterparts. The difference in maximum age between the sexes declined clinally from 7 years in the Hauraki Gulf to 3 years in Tasman Bay and 1 year in Pegasus Bay. Meuschenia scaber females tended to display heavier and larger body size than males at all three locations. Sex ratios varied among populations and with depth, suggesting females in the Hauraki Gulf and Tasman Bay may move into deeper water with age. Given the increasing global exploitation of monacanthids in multispecies fisheries and their long-living nature, our results provide valuable age-based demographic information essential for future conservation, monitoring and management programs.

Weed control and selectivity herbicides pre emerging in garlic cultivars

Background: Garlic cultivation is characterized by low capacity of competition with weed, mainly due to the characteristics of the canopy and it´s slow initial growth that make it difficult to cover the soil. Objective: This work aimed to evaluate the efficiency and selectivity of herbicides applied in the pre-emergence of two garlic cultivars in the edaphoclimatic condition of Santa Catarina State. Methods: Two experiments were carried out in the commercial garlic area with Ito and Chonan cultivars. Both experiments were conducted in randomized block design. The traits for Ito cultivar were without weed control, with weed control, with linuron (810 g ha-1), diuron (1,000 g ha-1), pendimethalin (1600 g ha-1), S-metolachlor (1200 g ha-1), oxyfluorfen (720 g ha-1) or flumioxazin (40 g ha-1). For the experiment with Chonan cultivar the treatment composed by oxadiazon (1000 g ha-1) was included. The analyzed variables were based on weed community control and phytotoxicity, stand, diameter of bulbs and productivity of garlic. Results: The infesting species of the experiment with the cultivar Ito were Stellaria media and Stachys arvensis, whereas for Chonan, only the first was found. The herbicides applied in pre-emergence were efficient in controlling these species until 45 days after application - DAA. The highest injuries at 45 DAA were caused by S-metolachlor, with 33% for Ito cultivar and 10% for Chonan. The best herbicides, taking into account weed control and productivity, were pendimethalin and S-metolachlor, for the Ito cultivar, and pendimethalin, oxyfluorfen, and flumioxazin for the Chonan cultivar. Conclusions: The pendimethalin stood out for presenting excellent weed control and being selective for both garlic cultivars.

The Effect of Crop Rotation, Tillage, Residue Management and N Fertilization Rate on Winter Wheat Growth and Development, Evaluated with an Optical Sensor

Crop growth and development, as well as yield, are the result of the efficiency of the chosen agricultural management system within the boundaries of the agro-ecological environment. End of season yield results do not permit the evaluation of within season management interactions with the production environment and do not allow for full understanding of the management practice applied. Crop growth and development were measured during the 2017, 2018 and 2019 crop cycles with an optical handheld NDVI sensor for all plots of the different management treatments of a long-term (since 2015) sustainability trial. Cropping systems varying in (1) crop rotation [winter wheat (Triticum aestivum L.) after maize (Zea mays L.), winter wheat (Triticum aestivum L.) after sunflower (Helianthus annuus L.) and winter wheat (Triticum aestivum L.) after winter pea (Pisum sativum L.)], (2) tillage (chisel tillage vs. no tillage), (3) residue management (chopped vs. anchored) and (4) N fertilization rate (N0, N50, N100 and N150) were compared. The NDVI handheld sensor was evaluated as a tool to monitor crop growth and development and was found to be an excellent tool for this purpose. The measurement with the handheld sensor was non-destructive and fast so that representative plot area could be measured easly and time efficiently. Crop rotation influnced early crop growth, with lower NDVI values for crops sown after maize and sunflower than crops after pea. The differences between the rotations diminished later in the growing season, and there was no advers effect on final yield. Fertilization rate significantly increased the NDVI values compared to non-fertilized plots. No tillage with residue retention, chopped or anchored, was characterized by a slower initial growth than chisel tillage practices, but this was compensated for by increased crop performance in the later stages. The results indicated that different rotation, tillage, residue management and N fertilization rate practices influence crop growth and development. It is important to monitor and understand crop growth under different management systems to select the right varieties and adjust timing and practice of input supply in each cropping system.

Weed management in greengram: A review

Greengram [Vigna radiata (L.) Wilczek], also known as mungbean, is extensively cultivated in India and other Asian countries. Being rich in protein, its grains are an important daily dietary component. Weeds are a major limiting factor in production of greengram that lead to a drastic reduction in yield. The presence of hardy weeds and slow initial crop growth compound this problem. Different strategies incorporating non-chemical and chemical methods have been practiced for efficient weed control in greengram. Non-chemical control methods include straw mulch (12–63% reduction in weed biomass), narrow row spacing (60–92% reduction in weed biomass), method of sowing (1–20% reduction in weed biomass), tillage practices (58% reduction in weed biomass), the frequency and rate of irrigation and fertilizer application (13–23% reduction in weed biomass), timing of hand weeding and selection of cropping system. Chemical control methods include the many herbicides with different selectivity and efficiency available for use in greengram. For efficient weed control, herbicides should be applied at the recommended rate and time in order to avoid inhibiting growth, symbiotic properties (number of nodules, dry weight of nodules, leghaemoglobin content in nodules) and grain yield in greengram crop. In this review, different weed management strategies including nonchemical and chemical weed control methods have been reviewed for their ability to control weeds in greengram. Furthermore, their influence on growth, symbiosis, yield and nutrient uptake of greengram, soil microflora and residual effect on succeeding crops have also been reviewed.

Growth Analysis of Sourgrass: Does Herbicide Resistance Affect Its Development?

Sourgrass (Digitaria insularis) is highlighted as one of the most troublesome weeds in Brazilian agriculture. The growth analysis of the species and biotypes with resistance to glyphosate are preponderant to support management strategies. In this way, the aim of this work is to compare the growth of biotypes resistant and susceptible to glyphosate, and to characterize the species growth in field conditions. The greenhouse experiment was installed in randomized blocks design, in factorial scheme 2 × 10, with eight replications. Factor A comprised the biotypes, and factor B the fortnight evaluations. The dry mass of roots, stems, leaves and shoot were assessed, besides leaf area and plant height. From these variables, the relative growth rate, net assimilation rate and leaf area ratio were calculated. For the field experiment, the same variables were assessed and the same parameters were calculated, without distinction on resistant or susceptible biotype. The biotype with resistance to glyphosate did not show adaptative disadvantages compared to the susceptible one. In this way, it is necessary to prevent the entry of resistant biotypes in cropped fields, as once established the area may not naturally return to the initial frequency of susceptible biotypes. Sourgrass shown slow initial growth and dry mass accumulation up to 42 days after emergence, indicating that control of this specie should be performed preferably before this period.