Evaluation of juvenile silver perch Bidyanus bidyanus (Mitchell) nutritional needs using high- and low-protein diets at two feeding levels

Juvenile silver perch Bidyanus bidyanus (Mitchell) of 3.2 g average weight were reared under controlled conditions on diets containing 23.4% and 40.6% protein. Diets were administered at 3% or 6% of the fish biomass per day. Both the protein concentrations and the feeding level of the diet influenced growth and proximate composition of the fish at the end of the 100-day growth trial. The energy requirement for these fish for maintenance was found to be 81.9 kcal × BW^–0.8 and, for each unit of energy retained per metabolic body weight, 7.05 needed to be supplied, whereas for each gram of protein retained per metabolic body weight, 5.79 g were required. The results indicate that it is possible to obtain the same weight increment when feeding a 23.4% protein diet at a level of 6% body mass day^–1 compared with only 3% body mass day^–1 of a 40.6% protein diet. This study provides the first estimation of nutrient requirements for juvenile silver perch, and these estimations require further refinement.     

Pottery manufacture in early Roman Galilee: a micromorphological study

The characteristics of, and the sources of the soil materials for, pottery groups manufactured in three ancient settlements of early Roman (late first century BC–first century AD) Galilee were studied by micromorphological techniques. The site-specific manufacturing proveniences of the three respective pottery groups have been previously demonstrated by chemical analysis. One of the sites, Kefar Hananya, is located near the geographical boundary between the Upper and Lower Galilee while the other two, Shikhin and Yodefat, are in the Lower Galilee. Each of the settlements made pottery from different soil types. In one case (Yodefat) temper was added to the main soil material. The Kefar Hananya pottery was made from noncalcareous Red Mediterranean soils (Terra-Rossa soil type) derived from hard limestone. Although most of the soils in the Galilee derive from Upper Cretaceous geological formations, the Kefar Hananya pottery was prepared from soils, found near that settlement, that were derived from Lower Cretaceous material rich in the kaolinite clay mineral. Micromorphological analysis of 41 randomly selected samples of the most common early Roman storage jar type thought to have been produced at Shikhin showed that all of the vessels were made from one of three soil types, Colluvial–Alluvial soils, Brown Grumusols, or Pale Rendzina. Study of the lithology and soils in the area of Shikhin showed that all three soil types derive from soil material eroded from the hilly area, on which the ancient settlement of Shikhin was built, into the adjacent valleys below the site. Samples of the Shikhin pottery group collected on the surface, in contrast with excavated samples, exhibit postdepositional carbonate infilling by dissolution and reprecipitation of the carbonates due to repeated exposure to water. No added temper was used for the preparation of either the Kefar Hananya or the Shikhin pottery groups. The Yodefat pottery, made from Rendzinic material rich in calcareous material, is of particular interest. This soil material contains about 70–80% calcareous material homogeneously mixed with the clayey plasma. In order to diminish the effect of the large amount of calcareous material and improve the properties of this raw material for pottery manufacture, leached clayey soil material of Terra-Rossa soil type was added as temper. The micromorphological comparison of the pottery groups and soil materials shows that two main factors influenced the raw-material procurement strategies of the potters of these settlements: the proximity of the soil material to the potters' settlement, and the suitability of the soil material for pottery manufacture.     

Evaluation of winter wheat as a source of high yield potential for the breeding of spring wheat

Grain yield components of high yielding European winter wheat varieties and of the best spring varieties grown in Israel were compared and their growth was analyzed. F₁- and F₂-populations of crosses between winter and spring varieties were tested. Under conditions in which winter wheat attained its normal kernel size which was similar to that of the spring varieties tested, it markedly outyielded spring wheat by means of its greater number of spikelets per spike. This advantage was also expressed in the F₂-populations and, was apparently, not linked with cold requirement. Winter wheat had a longer growing period and a greater leaf-area but a lower net assimilation rate than spring wheat. The higher total dry matter yield of winter wheat was owing to its longer growing period. The higher grain yield, however, was induced by a higher ratio of grain to total dry matter accumulated during the period of kernel development. The inheritance of several characters is discussed and it is concluded that winter wheat should be able to contribute to an increase in yield of progenies of its crosses with spring wheat.Contribution from The National and University Institute of Agriculture, Rehovot, No. E-1072. This research was supported by a grant of the Ford Foundation, Project Ford 4(A-3).     

Water use and the development of seasonal crop coefficients for Superior Seedless grapevines trained to an open-gable trellis system

Water consumption of table grapevines (Vitis vinifera cv. Superior Seedless) trained to a large open-canopy gable system was measured during six growing seasons (1999, 2001–2005) using 12 drainage lysimeters. The lysimeters (1.3 m³ each) were installed as part of a one-hectare vineyard in a semi-arid region in southern Israel. Water consumption of the lysimeter-grown vines (ET_c) was used as the basis for the calculation of irrigation applications in the vineyard. Three irrigation treatments, 80% (high), 60% (medium) and 40% (low) of ET_c of the lysimeter-grown vines, were applied in the vineyard. Reference evapotranspiration (ET_o) was calculated from regional meteorological data according to the Penman–Monteith equation. Seasonal curves for the crop coefficient (K _c) were calculated as K _c = ET_c/ET_o. Maximum ET_c values in different seasons ranged from 7.26 to 8.59 mm day⁻¹ and seasonal ET_c (from DOY 91 through DOY 304) ranged from 1,087 to 1,348 mm over the six growing seasons. Leaf area index (LAI) was measured monthly using the SunScan Canopy Analysis System. Maximum LAI ranged from 4.2 to 6.2 m² m⁻² for the 2002–2005 seasons. A second-order polynomial curve relating K _c to LAI (R² = 0.907, P < 0.0001) is proposed as the basis for efficient irrigation management. The effects of the irrigation treatments on canopy growth and yield are presented. The high ET_c and K _c values that were observed are explained by the wide canopy layout that characterize the large open-gable trellis system.     

Aspects of the benthic life cycle of Penaeus (Melicertus) japonicus Bate (Crustacea Decapoda) along the south-eastern coast of the Mediterranean

Recruitment, migration, growth, longevity and reproduction of Penaeus (Melicertus) japonicus Bate along the south-east coast of the Mediterranean were investigated.Relative population density, measured by catch per unit effort and average body length of the population were used in studying the recruitment, migration and growth of the various age groups.The reproductive state of the females was examined using three parameters: (1) gonado somatic index (ovary weight/total weight); (2) average diameter of ova; (3) morphological appearance of the ova according to a three stage scale.The results showed that P. japonicus migrates from inshore waters to the open sea during its benthic life cycle.Penaeus japonicus is distributed only on sandy substrate. It is suggested that the width of the longshore sandy strip determines the duration of the migration and hence the longevity and maximal growth of the individuals. Rate of migration might be accelerated by increasing density of young age groups near the shore. The estimated life span of each age group is 28–29 months. The maximal average body length of the population is 17 cm for males and 20 cm for females.Penaeus japonicus reproduce from April to November. This period corresponds to the appearance of a new age group about one kilometer offshore.The morphological appearance of the ova, average ovum diameter in each ovary and the female gonado-somatic index (GSI) are related to each other and can serve as a maturation index.Mature females are characterized by body length > 14 cm, GSI > 0.085 and average ovum diameter > 296 μ.     

Evaluation of some red tilapia strains for aquaculture: growth and colour segregation in hybrid progeny

Four red tilapia hybrids were evaluated for growth in earthen ponds and for colour distribution: ‘red’O. niloticus (L.) x O. niloticus (L.) or O. aureus (Steindachner). and O. niloticus or O. aureus x ‘white’ segregate of a Philippine red tilapia (Oreochromis sp.). The best growth was obtained in the ‘red’O. niloticus x O. niloticus and O. aureusx‘white’ hybrids, although they constituted only a little over 50% males. Of these two hybrids, the former is all-red, while the latter segregates into 35% red and 65% less attractive bronze-coloured individuals. Ways for establishing all-male populations of these two hybrids, for possible improvement of their performance, are discussed. Incompatibility between ‘red’O. niloticus females and O. aureus males, limiting fry production of this hybrid, was observed. The few fish of this hybrid obtained and tested proved to be all-male and all-red.     

Dynamics of phosphorus phytoavailability in soil amended with stabilized sewage sludge materials

Reducing the environmental risk of soluble P loss from sludge-amended soils is essential for increasing soils capacity to utilize sewage sludge beneficially. Fresh dewatered anaerobically digested sewage sludge (FSS), stabilized with ferrous sulphate (FeSul–SS), calcium oxide (CaO–SS) and aluminum sulphate (alum–SS), each at three chemical-to-FSS ratios, or by composting (BSC), was applied to alluvial soil at rates of 150 and 300 mg P kg^? 1 soil. Changes in P phytoavailability in comparison to KH₂PO₄-amended soil were probed during 100 days of incubation by a P-bioassay and were compared to the concentration of water-soluble P (WSP) and Olsen-P. P phytoavailability was notably linked to the incubation duration and the stabilization process. In general, P phytoavailability at equal P-addition rates was KH₂PO₄ > > alum–SS > BSC ≥ FSS > CaO–SS > > FeSul–SS; and it was positively related to the added P rates, although with quite different patterns among the various sludge products. The concentration of inorganic WSP (WSP_i) extracted from the soil increased following the application of FSS or BSC, and additional P mineralization further increased its concentration during incubation. In contrast, in most cases the chemically stabilized sludges, especially the FeSul–SS, showed considerably reduced inorganic WSP concentrations relative to the untreated soil. The total WSP, Olsen-P and organic WSP (WSP_o) positively correlated to P phytoavailability, indicating that WSP_o plays a role in plant P utilization in these soils. It is concluded that all the chemically stabilized sewage sludge studied effectively controlled WSP_i in soil while still supplying P to support plant growth.     

Life-table analyses for the tomato leaf miner,Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae): effects of plant genotype

BACKGROUND

Host plant resistance plays an important role in integrated pest management programs. Crop resistance assessments commonly focus on only a single dependent variable, such as larval survival/plant damage, which limits the ability to appreciate the impact of host plants on pest populations in the full sense. Therefore, we performed life-table analyses for tomato leaf miner Tuta absoluta, on 19 Solanum lycopersicum genotypes and a wild Solanum habrochaites accession. These analyses assess the ability of the pest to attain a high population density on different tomato genotypes. Based on the resulting ranking of tomato resistance at the vegetative stage (45-day-old plants), we tested the resistance of six selected genotypes at the reproductive stage (4-month-old plants).

RESULTS

T. absoluta performance was significantly inferior on vegetative-stage S. habrochaites plants (LA 1777); time taken for the first instars to mine the leaves (5 ± 0.14 days), development time of early- and late-stage larvae (8.8 ± 0.2 and 4.2 ± 0.2 days, respectively), pupal period (11.2 ± 0.58 days), and total developmental time (29.4 ± 0.83 days) were significantly longer, fecundity was significantly lower (18.66 ± 7.24 days), and the highest total mortality (63.33%) also recorded compared with other genotypes, resulting in the lowest net reproductive rate (R₀) (11.20 ± 2.51). For the six selected genotypes, the ranking of plant resistance did not change between plants at the vegetative and reproductive stages.

CONCLUSION

This study suggested that of 20 screened tomato genotypes, LA 1777 and EC-620343 are the least suitable hosts for T. absoluta to establish fast-growing populations, and thus can be employed in integrated T. absoluta management. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.