Yield quantitative trait loci from wild tomato are predominately expressed by the shoot.

Plant yield is the integrated outcome of processes taking place above and below ground. To explore genetic, environmental and developmental aspects of fruit yield in tomato, we phenotyped an introgression line (IL) population derived from a cross between the cultivated tomato (Solanum lycopersicum) and a wild species (Solanum pennellii). Both homozygous and heterozygous ILs were grown in irrigated and non-irrigated fields and evaluated for six yield components. Thirteen lines displayed transgressive segregation that increased agronomic yield consistently over 2 years and defined at least 11 independent yield-improving QTL. To determine if these QTL were expressed in the shoots or the roots of the plants, we conducted field trials of reciprocally grafted ILs; out of 13 lines with an effect on yield, 10 QTL were active in the shoot and only IL8-3 showed a consistent root effect. To further examine this unusual case, we evaluated the metabolic profiles of fruits from both the homo- and heterozygous lines for IL8-3 and compared these to those obtained from the fruit of their equivalent genotypes in the root effect population. We observed that several of these metabolic QTL, like the yield QTL, were root determined; however, further studies will be required to delineate the exact mechanism mediating this effect in this specific line. The results presented here suggest that genetic variation for root traits, in comparison to that present in the shoot, represents only a minor component in the determination of tomato fruit yield.

The effect of water harvesting techniques on runoff, sedimentation, and soil properties.

This study addressed the hydrological processes of runoff and sedimentation, soil moisture content, and properties under the effect of different water harvesting techniques (treatments). The study was conducted at three sites, representing environmental condition gradients, located in the southern part of the West Bank. For each treatment, the study evaluated soil chemical and physical properties, soil moisture at 30 cm depth, surface runoff and sedimentation at each site. Results showed that runoff is reduced by 65-85% and sedimentation by 58-69% in stone terraces and semi-circle bunds compared to the control at the semi-humid site. In addition, stone terraces and contour ridges significantly reduced the amount of total runoff by 80% and 73%, respectively, at the arid site. Soil moisture content was significantly increased by water harvesting techniques compared to the control in all treatments at the three study sites. In addition, the difference between the control and the water harvesting structures were higher in the arid and semi-arid areas than in the semi-humid area. Soil and water conservation, via utilization of water harvesting structures, is an effective principle for reducing the negative impact of high runoff intensity and subsequently increasing soil moisture storage from rainfall. Jessour systems in the valley and stone terraces were effective in increasing soil moisture storage, prolonging the growing season for natural vegetation, and decreasing the amount of supplemental irrigation required for growing fruit trees.

Evaluation of pre-alginate impression preparation methods in the surface accuracy of dental cast.

OBJECTIVE: The aim of this study was to investigate the influence of pre-preparation technique (finger smearing and saliva ejection) of alginate impressions on the quality and accuracy of dental casts. MATERIALS AND METHODS: Twenty mandibular impressions from 20 patients (10 males, 10 females) with an age range of 20-40 years were recorded using stock trays. A standard impression and pre-preparation technique for alginate were employed. This included removal of saliva with saliva ejector, smearing of alginate on occlusal surfaces of posterior teeth and smoothing of the material in the tray (Group-1: Test) and no drying and smearing or smoothing of the material prior to impression (Group-2: Control). Standardized disinfection, storage, pouring and removal from die stone techniques were used for all samples. Surface defects (nodules/blebs) on the occlusal surface of casts as examined with digital microscope, were classified according to their sizes and surface area into; Type-A (<500); Type-B (>500 <100); Type-C (>1000) in micrometers (µm). Data was tabulated and analyzed by SPSS using Anova and Tukey's test. RESULTS: Defects were significantly higher (p < 0.01) in samples in Group-2 (1225.51 ±â€¯823.44 µm) as compared to Group-1 (783.68 ±â€¯501.41 µm). All types of defects (Types A, B and C) were significantly higher in samples from Group-2 as compared to Group-1. CONCLUSIONS: Use of pre-preparation technique of finger smearing and saliva ejector prior to alginate impressions resulted in significant reduction of surface nodules/blebs and enhanced the quality and accuracy of fabricated casts. Therefore, the use of saliva ejector, finger smearing on the occlusal surface of teeth and smoothening of alginate impression, immediately prior to intra-oral placement is clinically recommended.

Resolution by recombination: breaking up Solanum pennellii introgressions.

Quantitative trait locus (QTL) genetics retains an important role in the study of biological and agronomic processes; however, its genetic resolution is often comparatively low. Community-based strategies are thus required to address this issue. Here we detail such a strategy wherein the widely used Solanum pennellii introgression lines (ILs) in the genetic background of the cultivated tomato (Solanum lycopersicum) are broken up into molecular marker-defined sublines as a community resource for map-based cloning.