Carbohydrate metabolism during the development of fruits of the tomato cultivar Micro-Tom was studied. The metabolism of the pericarp and placental tissues was found to be different. Starch was degraded more slowly in the placenta in comparison with the pericarp, whereas soluble sugars accumulated to a greater extent in the pericarp. The activities of glycolytic enzymes tended to peak at 40 days after flowering. Two of these, phosphoenolpyruvate phosphatase and pyruvate kinase, showed a dramatic increase in activity just before this peak, possibly indicating a role in up-regulating glycolysis to generate increased ATP that would be used during climacteric respiration. The expression of plastidial transporters was studied. Both the TPT and Glu6P transporter were expressed greatest in green fruits, before declining. The expression of the triose-phosphate transporter was greater than that of the glucose 6-phosphate transporter. The ATP/ADP transporter was expressed to a low level throughout fruit development.

A potato (Solanum tuberosum L.) cDNA coding for the chloroplastic isoform of fructose 1,6-bisphosphatase (cp-FBPase) was utilized to repress its activity in tomatoes (Lycopersicon esculentum Mill.) using antisense techniques. The patatin B33 promoter was used to ensure fruit specificity of the antisense effect. Transgenic plants were isolated in which fructose 1,6-bisphosphatase activity was reduced by more than 50% of the control in green fruits. Immunoblots indicated that the plastidial isoform was almost completely eliminated in the most strongly inhibited lines. Fruits of the transgenic plants were analyzed for levels of metabolites during fruit development. Glucose and fructose concentrations were increased in green fruits in the transgenic lines, but unchanged at later stages of development. The sucrose concentration was low, and was not significantly altered in the transgenic lines. There was net degradation of starch over the developmental period, but the starch content was not decreased. In green fruit the levels of hexose phosphates were unchanged, whilst the level of 3-phosphoglyceric acid was significantly increased in one line. Most importantly the deduced ratio of hexose phosphate to 3-phosphoglyceric acid decreased, consistent with an in vivo inhibition of fructose 1,6-bisphosphatase activity. One consequence of this reduction of in vivo activity of cp-FBPase was that the average weight of fully ripe fruits was significantly decreased by up to 20% in all transgenic lines in comparison with the control.

Five Egyptian parental genotypes of Faba bean were used for carrying out half diallel design to study heterosis and nature of gene action for earliness, vegetative, yield and yield components traits. Mean squares of genotypes were found to be highly significant for all studied traits. The results showed that the majority of crosses exhibited significant heterosis estimates for better parent for all studied traits. General combining ability (GCA) and specific combining ability (SCA) mean squares were highly significant for all studied traits. The results indicated that the magnitude of additive genetic variance (σ 2 A) were positive and lower than those of non additive (σ 2 D) one for all the studied traits, indicating that non additive gene action played a major role in the inheritance of different traits under study. The broad sense heritability estimates (H 2 b %) were more than their corresponding narrow sense heritability (H 2 n %) for all studied traits. However, estimates of narrow sense heritability were 34.2 and 14.8% for earliness traits and ranged from 15.2 to 29.8% for number of branches per plant and plant height, respectively. Respecting to yield components, the estimates of narrow sense heritability ranged from 8.8 to 70.9% for number of pod per plant and weight of 100 seed (g), respectively. The results showed that the two cultivar, Giza 843 (P 4 ) and Misr 2 (P1) was good general combiner for earliness, yield and yield components, respectively. The cross (P 1 xP 5 ) showed desirable SCA effects and significant heterosis values for earliness, and yield components. While, the two crosses, (P 1 xP 3 ) and (P 3 xP 4 ) exhibited desirable SCA effects for vegetative traits. These promising crosses could be used for breeding programs to produce pure lines.Key words: Faba bean, general combining ability (GCA), specific combining ability (SCA), heterosis, gene action. INRODUCTIONFaba bean (Vicia faba L.) is one of the most important pulse crops in Egypt; it is plays an important role in world agriculture due to the high protein content, its ability to fix atmospheric nitrogen and its capacity to grow and yield well on marginal lands (Alghamdi, 2007; Farag and Afia, 2012). Great efforts have been directed to improve yield level and quality properties in faba bean. In this trend, heterosis and combining ability provide important *Corresponding author. E-mail: naheif@yahoo.com. information for improving seed yield and other economic traits in faba bean. Superiority of hybrids over the better parent for seed yield and its attributes are associated with the magnitude of heterotic effects in important yield attributes, that is, number of branches per plant, pod setting percentage, number of pods per plant, 100-seed weight, shellout percentage and pod filling percentage. These heterotic effects may range from significantly positive to significantly negative for various traits according to genetic makeup of the parents Darwish et al., 2005;El-Hady et al., 2006; Farag and Afia, 2012).

The objective of this work was to evaluate the genetic variability among six cowpea (Vigna unguiculata) cultivars differing in their resistance to Callosobruchus maculatus (F.) weevil. Two resistant bean cultivars were used to compare between the sensitive, moderate tolerant, and high tolerant cowpea cultivars. The differentiations were performed by using random amplified polymorphic DNA (RAPD) fingerprinting, protein concentration and organic and non-organic components in seed coat. Six polymorphic primers were identified, resulting in different informative bands. Based on polymorphic profiles, three clusters were formed. Clustering was mainly affected by the resistance to weevil pest. The sensitive cowpea cultivars were separated in one group, the moderate tolerant and high tolerant cultivars came in separate groups, and finally, the resistant bean cultivars separated clearly in one distinct group. The most interesting result was represented by concentration of total protein in the seed coat. The protein concentration in the resistant bean cultivars were approximately 50% less than concentration in each of the moderate tolerant and sensitive cultivars of cowpea. Ferric ions were about 25% less than the moderate tolerant and sensitive cultivars. The concentrations of calcium and potassium in seed coats were higher in the resistant beans than in cowpea cultivars. Cobalt was about four times higher in resistant bean than in the sensitive and moderate tolerant cowpea cultivars, which may play a major role in seed resistance to weevil.

Five faba bean genotypes (Vicia faba L.) were selfed for two cycles to produce S1 and S2 generations. A half-diallel cross was carried out among them in each level of inbreeding (S0, S1 and S2) to obtain 10 F1 hybrids. Parental materials as well as their respective F1s were evaluated during the winter season of 2012. All studied traits except total dry seed yield showed significant inbreeding depression after the first generation of selfing (S1). No further decrease was noticed at the S2 generation. In the S1 generation the degree of inbreeding depression was highest for No. of branches/plant (−14.0%) and the least for weight of 100-seeds (−2.7). Some parents showed inbreeding vigor i.e. positive difference between S2 and S1 for some traits in S2 generation. Most studied traits showed significant positive heterosis values over mid-parent. The highest value of heterosis over the mid-parent was detected for total dry seed yield (128.8) and the lowest value of hybrid vigor was shown by weight of 100-seeds (1.2%). Specific combination among the 5 parental genotypes showed the highest value for heterosis for example cross Misr 2 × Giza 429 was the best cross for total dry seed yield, cross Giza 429 × Misr 1 for No. of branches/plant. Giza 429 is the best general combiner for most traits. Some crosses showed heterosis depression i.e. negative heterosis value in some traits. Hybridization among parental genotypes is recommended to be at the S1 or S2 generation. Twelve arbitrary primers produced different degrees of genetic polymorphism among the parental genotypes. A total of 65 amplification products were scored polymorphic. The percentage of polymorphic bands detected ranged from 33% to 100% with an average of 66.47%. The average of amplified bands was 5.42 polymorphic bands per primer. A positive, but non-significant, correlation (r = 0.085) between Euclidean distance and RAPD distance was observed.