Genetic analysis and phenotypic associations for drought tolerance in Hordeum spontaneum introgression lines using SSR and SNP markers

Associations between markers and drought related traits were investigated on a set of 57 advanced barley breeding lines, carrying various levels of introgression from Hordeum spontaneum lines 41-1 and 41-5, the best sources of drought tolerance in the ICARDA barley breeding program, using 74 simple sequences repeats (SSR) and 20 single nucleotide polymorphism markers. The 57 lines were evaluated for grain yield and drought related traits for three years (2003/04, 2004/05, 2005/06) in nine Mediterranean low rainfall environments. A high level of polymorphism was found with SSR markers, and the mean polymorphism information content and gene diversity values were 0.67 and 0.71, respectively. The number of alleles per locus varied from 2 to 11, with an average of 5.8 alleles per marker. Considering all the 57 lines, the linkage disequilibrium (LD) analysis was significant at a comparison-wise P?<?0.01 level in nearly 9 % of the SSR marker pairs used and a decay of LD was observed to a value of r ²?<?0.2 at a genetic distance of 40?cM. The association analysis revealed a total of 147 significant marker?Ctrait associations for grain yield and drought related traits. A total of 72 (49 %) marker?Ctrait associations showed favorable effects of the exotic germplasm where the H. spontaneum lines contributed to an improvement of the trait under drought stress conditions. The number of significant marker?Ctrait associations per trait were: 12 for growth habit; 2 for growth vigor; 11 for peduncle extrusion; 5 for number of grains per spike; 20 for peduncle length; 16 for days to heading; 20 for plant height; 8 for spike length; 17 for thousand kernel weight; 30 for grain yield; 4 for harvest index and 2 for biological yield. The phenotypic variation explained by individual marker?Ctrait associations ranged from 7.6 % to 36.2 %. The identification of genomic regions associated with grain yield and drought related traits is useful for the genetic improvement of cultivars better adapted to drought stress environments. Thus, the present study is encouraging in identifying significant marker?Ctrait associations through LD based association mapping analysis, which could complement and augment previous quantitative trait loci information for the potential use of Marker Assisted Selection for drought.     

Fire intensity and serotiny: response of germination and enzymatic activity in seeds of Pinus halepensis Mill. from southern Italy

? Context

The Mediterranean Basin is a fire-prone area. Pinus halepensis Mill. is a naturally growing conifer which is frequently used for reforestation and restoration as it displays some degree of adaption to fire. One of the traits conferring tolerance to fire is the frequent presence of serotinous cones that are thought to protect seeds from fire damage.

? Aim

We checked for the physiological responses of seeds to different intensities of fire and related them to the degree of serotiny of the cones.

? Methods

Germination percentage, mean germination rate and enzymatic activity (??-amylase and protease) were recorded for seeds burned either free or enclosed in cones. We included as experimental factors the following: fire intensity, serotiny and time during which seeds were stored in cones after harvesting and germination stage.

? Results

Burned seeds (released and enclosed) developed in serotinous cones exhibited higher heat insulation. In released seeds, germination was decreasing according to increasing fire intensity, although we found differences depending on site, serotiny and time stored after harvesting. The enzymatic activity was also found to be related to serotiny and fire intensity.

? Conclusion

Serotiny is an adaptive trait increasing the tolerance to fire which should be promoted in natural and restored populations.     

Influence of postharvest hot water treatment on nutritional and functional properties of kumquat (Fortunella japonica Lour. Swingle Cv. Ovale) fruit

The present study investigated the influence of a hot water dip (HWD) for 2 min at 50 degrees C, a standard and effective treatment for postharvest decay control of citrus fruit, on the nutritional and health-related properties of kumquats. The results show that most of the parameters examined, including titratable acidity, soluble solids content, maturity index, glucose, fructose, sucrose, ascorbic acid, dehydroascorbic acid, alpha- and gamma-tocopherols, beta-carotene, zeaxantin, rhoifolin, and antioxidant activity, were not significantly affected by treatment. The levels of beta-cryptoxanthin, narirutin, and total flavonoids increased after HWD, whereas lutein and total phenols decreased. The concentration of the essential oil and the relative percentage of the individual components of the essential oil were not affected by HWD except for the minor compound p-menta-1,5-dien-1-ol, which increased after HWD. After storage, lower levels of glucose, total sugars, beta-carotene, beta-cryptoxanthin and lutein were recorded in HWD fruit. A decrease in antioxidant activity and increases in alpha-tocopherol and total vitamin E were found both in control and HWD fruit. The influence of HWD at 50 degrees C for 2 min on individual nutraceuticals and health-related properties was thus generally low and may depend on storage conditions.     

Factors affecting the synergy of thiabendazole, sodium bicarbonate, and heat to control postharvest green mold of citrus fruit

The efficacy of thiabendazole (TBZ) to control postharvest decay caused by Penicillium digitatum of citrus fruit can be enhanced by co-application with sodium bicarbonate (SBC) and/or heat treatment. The impact of these treatments was investigated in citrus fruit, as a function of TBZ and SBC concentration and temperature, and were related to the amount of TBZ residues in fruit (total residues), in fruit surface, in the cuticular wax, and in the inner fruit. The residue levels of TBZ were determined in 'Valencia' oranges following a 1 min dip in an aqueous mixture of SBC at 0.5, 1, or 2 wt %/vol and TBZ at 600 or 400 mg/L (active ingredient, a.i.) at 20 or 40 degrees C and after 0 and 20 days at 17 degrees C and 90% relative humidity. The influence of SBC and heat on the TBZ residue concentration on the fruit surface, in cuticular wax, and on the inner cuticle tissue was determined in 'Salustiana' oranges after a 1 or 3 min dip in TBZ alone at 600 mg/L and 20 or 50 degrees C or for 1 min in TBZ at 600 mg/L and SBC at 2% and 20 degrees C. The efficacy of heat treatments with water, SBC, and TBZ, applied separately or in combination, was investigated on artificially inoculated 'Nova' mandarins and 'Valencia' oranges for the control of postharvest green mold caused by a TBZ-sensitive (TBZ-s) or TBZ-resistant (TBZ-r) isolate of P. digitatum. The residue levels of TBZ in fruit, evaluated as total residues, were not affected by the co-application of SBC in most samples. While TBZ residues in the fruit surface were not significantly affected by the dip temperature or by co-application of SBC, the rates of diffusion and penetration of TBZ into cuticular wax markedly increased in the presence of SBC or when TBZ was applied in combination with heat. TBZ residues in the inner tissue of fruits treated at 20 degrees C were not dependent upon the dip time or by the presence of SBC and were similar to those found in fruit treated with TBZ at 50 degrees C for 1 min, whereas significantly higher values were recorded in samples treated with TBZ at 50 degrees C for 3 min. When TBZ at 600 mg/L and 20 degrees C was applied in the presence of SBC at concentrations of 1-2 or 0.5-2%, it effectively reduced decay caused by the TBZ-resistant isolate of green mold in 'Nova' mandarins and 'Valencia' oranges. This treatment was also significantly more effective than TBZ alone to control green mold caused by a TBZ-s isolate in 'Valencia' oranges. The combination with SBC and mild heat (40 degrees C) and TBZ at 400 mg/L generally improved the control of a TBZ-r isolate of green mold with respect to the combined treatment at 20 degrees C. TBZ efficacy was also improved when applied at reduced rates (200 mg/L) and 50 degrees C, significantly suppressing green mold caused by a TBZ-s isolate of P. digitatum and effectively controlling a TBZ-r isolate. The rate of weight loss of 'Valencia' oranges was significantly increased by SBC treatment and was positively dependent upon the concentration of SBC used in the treatment, while the temperature of the treatment solution had little influence on later weight loss.     

Genetic diversity of ICARDA’s worldwide barley landrace collection

Twenty genic- and genomic SSR markers were used to study genetic diversity and geographical differentiation of barley from 29 countries through analysis of a worldwide collection of 304 ICARDA’s barley landraces. Of these, 19 loci were highly polymorphic in the material studied. Based on Nei-distance matrix, Principal Component Analysis (PCoA) and cluster analysis using UPGMA associated with AMOVA the data revealed countries’ grouping within regions. Three distinct germplasm pools were identified in the landraces. The first of these was from Eastern Africa (Eritrea and Ethiopia) and South America (Ecuador, Peru and Chile) suggesting that barley introduced to South America might have originated specifically from East Africa or that they share a common genetic basis for adaptation. The second was the Caucasus (Armenia and Georgia) and the third included the remaining regions of Central Asia, Near East, Northern Africa and Eastern Asia. Genetic diversity of barley subspecies (Six-rowed barley, Two-rowed barley, H. spontaneum C. Koch and H. agriocrithon Åberg) also discriminates them into three groups: cultivated barleys (Six-rowed barley and Two-rowed barley), wild barley H. spontaneum and subspecies H. agriocrithon. These results associated with parsimony analysis demonstrate that H. agriocrithon and H. spontaneum might be distinct and do not support a hybrid origin for H. agriocrithon suggesting further investigation of the basis of more intense sampling of the two subspecies H. spontaneum and H. agriocrithon.     

Multiple feather follicle cysts in a Moroseta hen (Gallus gallus)

An 8-month-old white feathered, black skinned Moroseta hen was presented for examination because of numerous 2 mm- to 30 mm-diameter irregularly shaped, hard nodules in the skin of the head, wings, back, and abdomen. The nodules were confined to the skin and did not involve subcutaneous tissues. Nodules consisted of dilated feather follicles packed with a caseous tan-to-pale-yellow material admixed with feather remnants. Histologically, affected feather follicles were markedly dilated and filled with laminated keratin debris. Necrosis of the epidermis and perifollicular lymphocyte infiltration was also present. Bacteriologic investigation of internal organs was negative, while secondary bacteria, Proteus spp. and Bacillus spp., were isolated from skin nodules. A concomitant lice infestation of Menopon spp., as well as leg mange caused by Cnemidocoptes spp., were also present. These bacterial isolates and parasites were not related to the disease condition. The condition observed was differentiated from benign feather follicle tumors, and a diagnosis of multiple feather follicle cysts was made. In addition, a breed predisposition was hypothesized.     

A new sustainable formulated feed based on discards from food industries for rearing the sea urchin Paracentrotus lividus (Lmk)

During a 18‐week experiment in a sea‐based system, Paracentrotus lividus was fed with two formulations of a new sustainable feed whose main ingredients were food farming discards, mostly outermost lettuce leaves, in different percentage. Egg white was added as protein source and binder, and a little amount of commercial fish feed was added as lipid source. At the end of the experiment, a high survival rate (>80%) and an increase in test diameter (22%), total weight (130%), gonad weight (240%) and gonad index expressed as size‐adjusted gonad weight (288%) were recorded. Gonads achieved a good colour and high levels of essential and polyunsaturated fatty acids, hence representing a commercially valuable product. Comparing the two feed formulations, the one with the lower lettuce content (57% vs. 67%) led to the best product quality, in terms of gonad features (gonad index and colour) and content of essential fatty acids. In order to move towards a higher sustainability of the aquaculture sector, this study proposes a low‐cost feed, produced with cheap and sustainable ingredients such as food farming discards.     

Genetic stability at nuclear and plastid DNA level in regenerated plants of <Emphasis Type="Italic">Solanum</Emphasis> species and hybrids

In this work we detected the extent of variability at nuclear and cytoplasmic DNA level of regenerated plants belonging to Solanum genotypes with a different genetic background and somatic chromosome number. As for the nuclear characterization, a total of 66 (18.5%) polymorphic bands were scored using 13 ISSR primers on 45 randomly selected regenerants. Our results show that the regenerants obtained from clone cmm 1T and, at lower level, those from cph 1C are unstable under in vitro conditions or rather more prone to in vitro-induced stress leading to somaclonal variation than the other genotypes used. Two types of changes were observed: disappearance of parental ISSR fragments, termed “loss”; appearance of novel ISSR fragments, termed “gain”. The most frequent event occurring in the regenerants was the loss of fragments (41 bands). Regenerated plants were analyzed with seven plastid universal primers to determine the cytoplasmic composition at chloroplast level. All cpDNA primer pairs tested produced amplicons of the same size in all genotypes analyzed and no polymorphic fragments were observed with any universal primers used. Our results show that under in vitro culture conditions genotype affects the integrity of the genome. In addition, the absence of polymorphism at plastid level confirms the greater genetic stability of cytoplasmic DNA.