Novel molecular marker associated with Tm2a gene conferring resistance to tomato mosaic virus in tomato

Tomato mosaic virus (ToMV) is an important Tobamovirus that causes significant crop losses. Resistance to the ToMV is conferred by the genes Tm1, Tm2 and Tm2^a. Among these three genes, Tm2^a confers resistance to most strains of the ToMV. Screening of genetic lines under field conditions based on phenotype is time‐consuming and challenging due to concerns associated with stability of the virus and its potential transmission to other plants. Tightly linked molecular markers associated with resistance genes can improve selection efficiency and avoid these problems. This study developed a PCR‐based marker based on restriction site differences from Tm2^a locus‐specific sequences, which was found to be useful in identifying the resistant and susceptible genotypes and was consistent with phenotypic data. The marker is a codominant cleaved amplified polymorphic sequence (CAPS) marker producing 270‐ and 600‐bp DNA fragments from resistant genotypes and an 870‐bp fragment from susceptible genotypes when digested with HaeIII restriction enzyme. This novel marker can be useful for tomato breeders to screen progeny from segregating populations for ToMV resistance.     

Quantitative Genetic Analysis of Traits in Avocado Cultivars *

This research is aimed at quantitative genetic analysis of several avocado traits and cultivars. The experimental material consists of our avocado breeding project in which data were collected from several crosses as well as selfings of cultivars. Parenthood was determined by isozymes and the seedling progenies were assessed for eight traits. A biometrical genetic approach for analysis of this breeding project is presented. Genetic profiles of the traits and cultivars were detailed by several characteristics: level of heterozygosity and dominance deviation, dominance of alleles, dominance direction, general evaluation of additive and non-additive genetic variance, maternal inheritance, and allelic differences among the various cultivars in major genes controlling the same quantitative trait. Five avocado cultivars: ‘Fuerte’, ‘Hass’, ‘Ettinger’, ‘Tova’, and ‘Rosh-Hanikra’, were characterized separately for each trait. Practical conclusions for the breeder regarding economically important quantitative traits are discussed.     

The effect of 3,3′,5-triiodo-L-thyronine and 17-α-methyltestosterone on growth and body composition of the glass stage of the eel (Anguilla anguilla L)

This study was undertaken to determine the influence of orally administered 3,3,5-triiodo-L-thyronine (T₃) or 17--methyltestosterone (MT) on growth and body composition of the eel (Anguilla anguilla L.) during the glass stage.Elvers receiving 20 or 40 ppm of T₃ in the food weighed significantly more (P < 0.05) than controls. However, after 61 days of treatment a dosage of 60 ppm was not efficacious.Terminal percentages of body protein were significantly lower (P < 0.05) in elvers that received 20 ppm or 40 ppm T₃ in their diets, than in the control. Crude body fat content was higher (P < 0.05) in elvers receiving 20 ppm (29% fat) or 40 ppm (28% fat), than in the controls (26% fat). Compared to the control, diets containing T₃ at 20 or 40 ppm increased the body glucose concentration.Glass eels fed a diet containing 1 or 10 ppm MT grew significantly more slowly (P < 0.05) than the controls.Total body protein content was higher (P < 0.05), but total body crude fat content was lower (P < 0.05) in elvers fed a diet with 1 or 10 ppm MT compared to the controls. Total body glucose concentration of elvers administered 10 ppm MT was significantly lower (P < 0.05) than that of the control groups.     

The influence of phytoestrogens and oestradiol-17β on growth and sex determination in the European eel (Anguilla anguilla)

Under aquaculture conditions, European eels (Anguilla anguilla) produce a high percentage of males (80–95%) that normally stop growing at 100–200 g. Females continue to grow to 500–750 g and obtain higher market value. Therefore, increasing the percentage of females in a population would be beneficial to the culture of eels. The present study was carried out in order to examine the effect of oestradiol and phytooestrogens on sex differentiation and growth rate of eels. Juvenile European eels with undifferentiated gonads were fed pellets containing oestradiol‐17β (E2) or phytooestrogens for 100–150 days. Feeding E2 resulted in 50–61% increase in body weight compared with the control. Oestradiol‐17β and phytooestrogens both elevated significantly the percentage of females in the population. Feeding E2 at 20 mg kg^?1 feed resulted in 70% females, while lower concentration of E2 (2 mg kg^?1) resulted in only 30% after 100 days (Experiment 1). The same dose given for 150 days (Experiment 2) resulted in 88% females, indicating that both, the concentration and duration of E2 treatments had a significant effect on sex differentiation. Fish fed genistein at 2 mg kg^?1 for 100 days, resulted in 55% of females, but at a higher dose of 20 mg kg^?1 there were only 15% females. These results demonstrate that phytooestrogens can be used as alternatives to gonadal steroids for sex manipulation in eels, but the optimal concentrations and duration are still to be determined.     

Application of RAPD and cytochrome b sequences to the study of genetic variations in F1 and F2 generations of two different strains of guppy (Poecilia reticulata, Peter 1854)

The DNA of two laboratory strains of guppy (Poecilia reticulata), Black Yellow (BYS) and Red Flame (RFS), was studied with respect to their colour differences, in two generations (F₁ and F₂). Their varying morphological colours were related to their cloned fragments of cytochrome b mitochondrial DNA (mtDNA) and random‐amplified polymorphic DNA‐polymerase chain reaction (RAPD‐PCR). The F₁ generation was characterized by various forms. The male BYS could be divided into 68% having black–yellow tails and 14% having black–yellow–red tails. The other variations were found in very low percentages. The percentage of black–yellow‐tailed males increased to 85 in the F₂ generation, and the percentages of the various other forms consequently decreased. Only 63% of BYS males had black–yellow dorsal fins in the F₁ generation, but this percentage increased to 84 in F₂. Compared with the males, fewer variations were found in female colour patterns in the F₁ generation. A high percentage of BYS females (81%) colour was found with no significant increase in the F₂ generation. However, variations decreased in the F₂ females. On the other hand, a very high variation was found in female fins in the F₁ generation: only 32% were of BYS colour and 25% had no‐colour fins. However, a significant increase in BYS colour was found in the F₂ generation (61%) and 39% had no colour. The variation in RFS was lower than BYS in the F₁ generation: 81% of the F₁ males had red–yellow tails with colour, 46% of the fins were yellow and 36% were red–white. In females, a very high percentage (84%) had red–yellow tails and 76% had no‐colour dorsal fins. Mitochondria DNA markers and genomic DNA were studied in various laboratory strains. In the clone of the fragments of cytochrome b, the bands correlated to the colour phenotype. A fragment of the cDNA sequence was determined from a 268‐bp cloned with fragments of the guppy cytochrome b mtDNA gene. The genes varied for the two strains in only two base pairs, starting at the nucleotide position 171 and ending at position 174. Three primers showed good results in the RAPD‐PCR and were found suitable for the study of DNA variations in guppy. The high variation detected in BYS, in comparison with RFS, was reflected by changes in band‐sharing (BS) values ranging from 0.66 to 1, versus 0.8 to 1 in RFS.     

Effect of protein level in purified diet and of density,ammonia and O2 level on growth of juvenile European eels (Anguilla anguilla L.)

The influence of protein level in a purified diet and of density on the growth of Anguilla anguilla in indoor and outdoor containers was examined. The average weight increase of eels that were fed on a diet of pellets containing 35%, 45%, or 55% protein was significantly higher than the mean weight increase of eels fed on pellets containing 25% protein. The production per m³ was higher in the groups fed 45% or 55% protein level in the diet than in the groups fed 25% or 35% protein. Dissolved oxygen in the water of the growing tanks was 7–9 ppm in all groups. Ammonia production was lower in the group fed on pellets containing 25% protein and higher in the groups receiving higher protein diets.Eel growth at low density (4 kg/m³) was almost the same as at high density (30 kg/m³) for both slowly growing and moderately growing eels. Production was higher in the groups stocked at high density and lower in those stocked at low densities. The production of slowly growing eels was lower than that of moderately growing eels.     

The digestibility of nutrient sources for common carp, Cyprinus carpio Linnaeus

The apparent digestibility of protein, fats, carbohydrate and energy within three feed ingredients (wheat, barley and corn) for common carp, Cyprinus carpio Linnaeus, was studied, using chromic oxide as a dietary marker. Each experimental diet consisted of a mixture of the test ingredient and 50% basal diet (containing 50% soybean meal, 35% wheat meal, 10% soybean oil, plus 5% vitamins, egg yolk, guar and chromic oxide). It was found that in wheat meal the protein had an apparent digestibility of 92%, and the lipid an apparent digestibility of 80%. The apparent digestibility of corn was 81% for protein and 90% for lipid, while for barley the figures were 73% and 67%, respectively. For apparent digestible energy, the figures were 12.39 kJ g^?1 for wheat, 6.69 kJ g^?1 for barley and 9.32 kJ g^?1 for corn.     

Concentrating Immunoprotective Phytoactive Compounds from Fruits and Vegetables into Shelf-stable Protein-rich Ingredients

Co-delivery of edible proteins with health-protective fruit (muscadine grape) and vegetable (kale) phytoactive compounds was accomplished in a biofortified ingredient for use in convenient, portable food formulations. Polyphenolics were concentrated (10–42 mg/g range) in dry muscadine-protein matrices. Kale-fortified protein matrices also captured polyphenolics (8 mg/g), carotenoids (69 μg/g) and glucosinolates (7 μmol/g). Neither total phenolics nor glucosinolates were significantly diminished even after long term (6 months) storage at 4, 20, or 37 °C, whereas carotenoids degraded over time, particularly at higher temperatures. Dry biofortified phytoactive-protein ingredients allowed delivery of immunoprotective compounds from fruits and vegetables in a stable, lightweight matrix.     

Evaluation of rumen-protected choline additive to diet on productive performance of male Zaraibi growing goats during hot summer season in Egypt

Twenty Zaraibi goat bucks were used in this experiment which lasted 3 months during summer season of Egypt. The animals were divided randomly into two equal groups. The first group was kept without treatment as control while in the second group, rumen-protected choline (RPC) at the level of 20 g/buck/day was added to the concentrate feed mixture at the morning feeding. RPC additives to diet of Zaraibi goat bucks during the period of hot summer season increased (P < 0.01) total gain and average daily gain compared to the control group. RPC increased (P < 0.05) dry matter intake and feed conversion while water intake was not affected by RPC additives. RPC increased (P < 0.05) red and white blood cell (RBC × 10⁶, WBC × 10³) counts and hemoglobin concentration and hematocrit percentage. RPC increased total protein (P < 0.05), globulin, and γ-globulin (P < 0.01). On the other hand, total lipids, total cholesterol, and triglyceride concentrations decreased (P < 0.05 and P < 0.05) while phospholipids, glucose, and choline concentrations increased (P < 0.01) due to RPC supplementation. RPC increased (P < 0.01) thyroxin and triiodothyronine, increased (P < 0.05) testosterone levels, and decreased (P < 0.01) cortisol level compared with control bucks. It is concluded that dietary RPC at the rate of 20 g daily is required for growing male goats, especially, under heat stress conditions of summer season in Egypt and showed the best results concerning the growth, feed conversion, blood metabolites, and economic efficiency.