The prediction of bread wheat quality: joint use of the phenotypic information brought by technological tests and the genetic information brought by HMW and LMW glutenin subunits

Attempts have been made to predict Chopin alveograph or French bread-making tests, using tree-based models and PLS regressions. Data came from three sets of trials, involving 130, 214 and 103 different genotypes, which were described for HMW-GS, LMW-GS and small-scale tests currently used in breeding programs. Segmentation trees and PLS regressions indicated that HMW-GS and LMW-GS were not sufficient to explain alone the variability of bread wheat quality. This could be partly due to “allele × environment” and “locus × locus” interactions. For HMW-GS, Glu-B1 was the predominant locus for alveograph and French bread-baking, and some differences in the alleles hierarchy were demonstrated according to the end-use parameter considered. For LMW-GS, Glu-B3 seemed to be preponderant, with alleles b′, c and g being favourable and allele c′ unfavourable. Joint use of the information brought by glutenin subunits and technological tests did not enable to predict satisfactorily, neither the different parameters of French bread-baking, nor the extensibility L of alveograph. Only the prediction of the strength W proved reliable, and robust PLS equations were proposed for this alveograph parameter. These prediction equations could be of interest to select for high values of W in the mid generations of breeding.     

Quantitative trait loci associated with trichomes in the <Emphasis Type="Italic">Solanum galapagense</Emphasis> accession LA1401

Pest resistance in Solanum galapagense has been associated with the presence of type IV glandular trichomes and allelochemicals. Knowledge of the genetic factors involved in determining the presence and type of trichomes may assist in the process of gene introgression for development of pest resistant tomato cultivars. In this study, we sought to identify QTLs associated with the presence of type IV trichomes in an F₂ population derived from the interspecific cross of Solanum lycopersicum TOM-684?×?S. galapagense accession LA1401. Two QTLs contributing to type IV trichome occurrence and density were detected, one major QTL (gal.IV-2), responsible for 35.22% of phenotypic variation, was located on chromosome 2. The other QTL (gal.IV-3) was located on chromosome 3, and explained 23.35% of the phenotypic variation in the F₂ population. These QTLs were responsible for 26.44 and 3.37% of the variation observed in a progeny derived from a backcross to TOM-684. The same QTLs were also associated with type II?+?III non-glandular trichomes, whose densities were negatively correlated to those of type IV trichomes, suggesting that the loci found may have pleiotropic effects for high type IV/low type II?+?III trichome densities. Our results indicate that the inheritance for type IV trichomes can be explained by a few genetic factors affecting the presence of a gland and the density of trichomes. These results further suggest a revision to trichome classification used for tomato may be appropriate.     

Conserving seeds of useful wild plants in Mexico: main issues and recommendations

The efficient storage and germination of seeds underpin the effective use of plants for livelihoods and sustainable development. A total of 204 wild species useful for local communities of the Tehuacán–Cuicatlán Valley were collected and stored in seed banks in country for long term conservation, and 66 % (i.e., 134) duplicated in the U.K., as an effective means of ex situ conservation. Of the 204 species, 147 (122 of which also duplicated in the U.K.) were previously listed as useful plants in the ethnofloristic inventory of the Valley. Based on literature surveys, we found that one of the major impediments to the use of stored seeds of wild species is the lack of knowledge of how to germinate the seed. In detailed studies, we found that seeds of 18 useful plant species from 10 different families germinated readily and could be propagated. In contrast, four species (Actinocheita filicina, Bursera submoniliformis, Karwinskia mollis and Lippia graveolens) produced dormant seeds and therefore further studies are needed before their use can be maximised in large scale propagation programmes in support of conservation and livelihoods. Overall, this large-scale study on useful wild plant species in Mexico confirms that conventional seed banking can effectively support sustainable development and livelihood programmes.     

The role of <Emphasis Type="Italic">Euwallacea</Emphasis> nr. <Emphasis Type="Italic">fornicatus</Emphasis> (Coleoptera: Scolytinae) in the wilt syndrome of avocado trees in Israel

The polyphagous shot hole borer (PSHB), Euwallacea nr. fornicatus (Coleoptera; Scolytinae) has become a serious threat to the avocado industry and several shade tree species in Israel. Branch wilting and tree mortality is the outcome of PSHB galleries. Understanding the relationship between avocado trees and the PSHB is required for considering management strategies. In Israel, 52 tree species from 26 botanical families were attacked by the PSHB, but only 12 species were suitable for beetle reproduction. All examined avocado cultivars were attacked, but ‘Hass’ most severely. Large and medium diameter avocado branches were more resistant to PSHB, compared to thin branches. Effectively, gallery density increased as branch diameter decreased. Concomitantly, in large and medium diameter branches, extensive sugar exudation occurred and beetle attack rarely progressed to the formation of natal galleries, whereas minimal sugar exudation was observed in thin branches. This was more evident in those that were weakened by repeated attacks followed by successful beetle colonization. PSHB prefers and successfully colonized branches that had been previously attacked by its conspecifics, and reproduction was much higher in these branches, as opposed to initial attacks. Lesion frequencies increased from late spring (April) until late summer (September). Avocado branches at the early stages of beetle colonization may be identified by sugar exudation at the base of the thin branches. The main approach for reducing damage caused by the PSHB is sanitation, achieved by the removal of colonized branches and intact infested pruned slash.     

Effect of application timing and method on efficacy and phytotoxicity of 1,3-D, chloropicrin and metam-sodium combinations in squash plasticulture

BACKGROUND: Metam-sodium, 1,3-dichloropropene (1,3-D) and chloropicrin are widely used soil fumigants. Combined application of metam-sodium and 1,3-D + chloropicrin is intended to improve efficacy and broaden spectrum of control, but little is known about the effect on crop safety. This study aimed to evaluate the effects of application timing of fumigant combinations on soilborne pest and disease control (nematodes, soil fungi and weeds) and growth of squash. Two separate tests with chisel-injected and drip-applied fumigant combinations and plant-back times ranging from 1 to 4 weeks were conducted in Tifton, GA, USA, in spring and fall 2002. RESULTS: Fumigant combinations using 1,3-D, chloropicrin and metam-sodium were as effective as methyl bromide in controlling Meloidogyne incognita (Kofoid & White) Chitwood, Pythium irregulare Buis., Rhizoctonia solani Kühn and Cyperus esculentus L. Chisel-applied combinations were more effective in terms of root-knot nematode control than drip-applied combinations. Root-knot nematode reduced squash yields by up to 60%. Phytotoxicity problems and lower yields were observed during spring, especially following 1,3-D + chloropicrin and when plant-back periods were shorter. CONCLUSION: The main problem with fumigant alternatives to methyl bromide may not be reduced efficacy but, in particular for 1,3-D products, loss of flexibility in terms of longer plant-back periods.     

Multicentric mast cell tumors in a horse

Abstract: A 6‐year‐old female Rocky Mountain horse was presented for evaluation of draining tracts and distal limb subcutaneous edema on the left front and left hind limbs that had been present for 2 weeks. Direct smears of fluid collected by fine‐needle aspiration of subcutaneous fluid from both limbs were highly cellular with a predominance of eosinophils accompanied by numerous, moderately atypical, variably granulated mast cells. The cytologic diagnosis was mast cell tumor (MCT) with prominent eosinophilic infiltration with a differential diagnosis of eosinophilic granuloma. Histologic evaluation of surgical biopsies of lesions from both limbs was performed on sections stained with H&E, toluidine blue, and Luna stains. The histologic diagnosis was MCT, and staining with toluidine blue and Luna stains confirmed the presence of mast cells and eosinophils, respectively. In addition, the mast cells strongly expressed CD117. This is the first reported case of cutaneous mast cell neoplasia in a horse in which primary presenting complaints were draining tracts and distal limb subcutaneous edema involving multiple limbs. This case illustrates the utility of staining for CD117 expression in combination with traditional stains, such as toluidine blue and Luna, in differentiating MCTs from other eosinophilic lesions in horses.     

Dye injection for predicting pesticide movement in micro-irrigated polyethylene film mulch beds

A new method is described for tracing water movement in polyethylene film covered soil beds. Dye was delivered via a drip tape micro-irrigation system which was placed in the bed as the soil beds were shaped and covered with polyethylene film. The dye was injected into the system and irrigated with water for 4-24 h at 0.41-1.38 bar (41-138 kPa) pressure depending on the experiment. The dye appeared as blue circles on the soil surface within 20 min of injection and produced a three-dimensional pattern in the soil profile. Injection-irrigation-pressure scenarios were evaluated by measuring dye movement directly below and between emitters by sliding fabricated blades vertically into the bed at the desired examination point and excavating the soil away from the blade. The dye typically produced a U shape on the face of the bed and the area was calculated for each of these exposed faces. The area increased as the length of irrigation and water pressure increased. Interrupted irrigation (pulsing) scenarios did not alter the calculated areas encompassed by the dye compared to uninterrupted irrigation scenarios. The blue dye provided a direct, inexpensive and easy method of visualizing water movement in soil beds. This information will be used to optimize application of emulsifiable plant-care products in polyethylene film mulch beds.     

Type of smear may influence thrombopoietic cell counts in the bone marrow of clinically healthy dogs

BACKGROUND: The expected number of thrombopoietic cells in normal canine bone marrow is poorly defined and there is no consensus on the most appropriate way to prepare cytologic smears to evaluate these cells nor on the optimum method for their quantification. OBJECTIVE: The purpose of this study was to determine total and differential counts of thrombopoietic cells in the bone marrow of clinically healthy Beagle dogs by comparing 4 different smear types and bone marrow core biopsies. METHODS: Twenty-two clinically healthy, male Beagle dogs, 10 to 12 months old, were used in the study. Following bone marrow aspiration and core biopsy from the iliac crest, Giemsa-stained smears were prepared by 4 techniques: drop-squash, particle-squash, buffy coat, and fat-layer smears. Thrombopoietic cells were counted in up to 100 low-power fields (LPF, X10 objective) in the aspiration smears and in all possible high-power fields (HPF, X40 objective) in H&E-stained biopsy sections. RESULTS: Mean total thrombopoietic cell counts were 2.76 cells/LPF (drop-squash), 1.55 cells/LPF (particle-squash), 8.05 cells/LPF (buffy coat), and 3.08 cells/LPF (fat-layer). Core biopsies yielded 5.31 cells/HPF but frequently failed to provide interpretable specimens. There was a significant difference in cell counts among the 4 smear types (P <.001). Based on evaluation of buffy coat smears, thrombopoietic cells included 1.23% megakaryoblasts, 8.77% promegakaryocytes, and 90% megakaryocytes, with a mean maturation index of 0.11. CONCLUSION: Thrombopoietic cell counts in canine bone marrow are influenced by the smear technique. Buffy coat and fat-layer smears may be useful to obtain cellular smears in hemodiluted or small aspirate samples.