The use of iron-efficient rootstocks can be a sustainable way to enhance iron (Fe) fruit content in tomato. A hybrid tomato variety was grafted on a genotyped population of recombinant inbred lines ...derived from
Solanum pimpinellifolium,
and compared with self- and non-grafted controls under low iron (5.2 µM) growing conditions. Rootstock effects on total fruit yield, fruit Fe and yield Fe content (FeUEc) were the target traits; other minerals were also investigated by quantitative trait loci (QTL) and candidate gene analyses. The rootstock genotype affected fruit concentrations of Fe, Ca, Mg, Mn, Na, P, S, Si and Al. Most rootstocks increased FeUEc. Fruit and leaf Fe and FeUEc were genetically complex, involving epistatic interactions. Six and eight QTLs were detected for these traits, respectively, by multiple QTL mapping. Two kinds of relevant genes were found among candidates within QTLs for iron related traits: those coding for secretory proteins specific of the tomato xylem sap under iron deficiency, and others having a role in iron uptake such as TOMLHA1, FRO1, NRAMP2, FER and MYB72. Detected QTLs might reflect differences in the regulatory regions of those relevant genes, more than in their coding sequences.
Seventeen Middle Pleistocene crania from the Sima de los Huesos site (Atapuerca, Spain) are analyzed, including seven new specimens. This sample makes it possible to thoroughly characterize a Middle ...Pleistocene hominin paleodeme and to address hypotheses about the origin and evolution of the Neandertals. Using a variety of techniques, the hominin-bearing layer could be reassigned to a period around 430,000 years ago. The sample shows a consistent morphological pattern with derived Neandertal features present in the face and anterior vault, many of which are related to the masticatory apparatus. This suggests that facial modification was the first step in the evolution of the Neandertal lineage, pointing to a mosaic pattern of evolution, with different anatomical and functional modules evolving at different rates.
Key message
Rootstock HKT1 genotype affected fruit Na
+
and non-commercial fruit yield; QTL analysis of rootstock-mediated scion nutrition is a powerful forward genetic approach to identify wild ...genes for rootstock breeding.
The present study approaches the QTL dissection of rootstock effects on a commercial hybrid variety grafted on a population of RILs derived from
Solanum pimpinellifolium,
genotyped for 4370 segregating SNPs from the SolCAP tomato panel and grown under moderate salinity. Results are compared to those previously obtained under high salinity. The most likely functional candidate genes controlling the scion Na
+
were rootstock
HKT1;1
and
HKT1;2
as it was previously reported for non-grafted genotypes. The higher fruit Na
+
found when rootstock genotype was homozygote for
SpHKT1
supports the thesis that scion HKT1 is loading Na
+
into the phloem sap in leaves and unloading it in sink organs. A significant increment of small, mostly seedless, fruits was found associated with
SlHKT1
homozygous rootstocks. Just grafting increased the incidence of blossom end rot and delayed fruit maturation but there were rootstock RILs that increased commercial fruit yield under moderate salinity. The heritability and number of QTLs involved were lower and different than those found under high salinity. Four large contributing (>17 %) rootstock QTLs, controlling the leaf concentrations of B, K, Mg and Mo were detected whose 2 Mbp physical intervals contained B, K, Mg and Mo transporter-coding genes, respectively. Since a minimum of 3 QTLs (two of them coincident with leaf K and Ca QTLs) were also found governing rootstock-mediated soluble-solids content of the fruit under moderate salinity, grafting desirable crop varieties on stress-tolerant rootstocks tenders an opportunity to increase both salt tolerance and quality.
Onofri A, Carbonell EA, Piepho H‐P, Mortimer AM & Cousens RD (2010). Current statistical issues in Weed Research. Weed Research50, 5–24.
Summary
The correct design of experimental studies, the ...selection of the appropriate statistical analysis of data and the efficient presentation of results are key to the good conduct and communication of science. The last Guidance for the use and presentation of statistics in Weed Research was published in 1988. Since then, there have been developments in both the scope of research covered by the journal and in the statistical techniques available. This paper addresses the changes in statistics and provides a reference work that will aid researchers in the design and analysis of their work. It will also provide guidance for editors and reviewers. The paper is organised into sections, which will aid the selection of relevant paragraphs, as we recognise that particular approaches require particular statistical analysis. It also uses examples, questions and checklists, so that non‐specialists can work towards the correct approach. Statistics can be complex, so knowing when to seek specialist advice is important. The structure and layout of this contribution should help weed scientists, but it cannot provide a comprehensive guide to every technique. Therefore, we provide references to further reading. We would like to reinforce the idea that statistical methods are not a set of recipes whose mindless application is required by convention; each experiment or study may involve subtleties that these guidelines cannot cover. Nevertheless, we anticipate that this paper will help weed scientists in their initial designs for research, in the analysis of data and in the presentation of results for publication.
We carry out a new paleomagnetic study across stratigraphic layer TD7 of Gran Dolina Site, Atapuerca, and reassess the existing absolute ages (thermoluminescence, electron spin resonance) obtained at ...this site. The new and more detailed magnetostratigraphic record of the Matuyama-Brunhes boundary, combined with absolute ages, enables further constraint on the age of the underlying human-bearing level or Aurora Stratum. Paleomagnetism of the studied silts and sandstones reveals stable, dual polarity Characteristic Remanent Magnetization directions. A new normal magnetic polarity short interval is found at several consecutive sampling localities in the upper part of TD7, providing a new ante quem date for the human-bearing sediments of 0.9 Ma, possibly formed during MIS 25.
•A new paleomagnetic study of stratigraphic layer TD7 of Gran Dolina Site, Atapuerca.•Existing TL, OSL, and US-ESR ages are reassessed.•A new normal magnetic polarity short interval is reported.•The ante quem date for the human-bearing sediments is 0.9 Ma.
Ascertaining the timing of the peopling of Europe, after the first out-of-Africa demographic expansion at the end of the Pliocene, is of great interest to paleoanthropologists. One of the earliest ...direct evidences for fossil hominins in western Europe comes from an infilled karstic cave site called Gran Dolina at Atapuerca, in a stratum ∼1.5
m below the Brunhes–Matuyama (B–M) geomagnetic boundary (780
ka) within lithostratigraphic unit TD6. However, most of the meters of fossil- and tool-bearing strata at Gran Dolina have been difficult to date. Therefore, we applied both thermoluminescence (TL) and infrared-stimulated-luminescence (IRSL) multi-aliquot dating methods to fine-silt fractions from sediment samples within Gran Dolina and the nearby Galería cave site. We also applied these methods to samples from the present-day surface soils on the surrounding limestone hill slopes to test the luminescence-clock-zeroing-by-daylight assumption. Within the uppermost 4
m of the cave deposits at Gran Dolina, TL and paired TL and IRSL ages range stratigraphically from 198
±
19
ka to 244
±
26
ka. Throughout Gran Dolina, all luminescence results are stratigraphically self-consistent and, excepting results from two stratigraphic units, are consistent with prior ESR-U-series ages from progressively deeper strata. Thermoluminescence ages culminate at 960
±
120
ka approximately 1
m below the 780
ka B–M boundary. At Galería, with one exception, TL and IRSL ages range stratigraphically downward from 185
±
26
ka to 503
±
95
ka at the base of the lowermost surface-inwash facies. These results indicate that TL and (sometimes) IRSL are useful dating tools for karstic inwash sediments older than ca. 100
ka, and that a more accurate chronostratigraphic correlation is now possible among the main Atapuerca sites (Gran Dolina, Galería, Sima de los Huesos). Furthermore, the oldest TL age of ca. 960
ka from Gran Dolina, consistent with biostratigraphic and paleomagnetic evidence, implies a probable numeric age of 900–950
ka for the oldest hominin remains (∼0.8
m below the TL sample). This age window suggests a correspondence to Marine Isotope Stage (MIS) 25, a relatively warm and humid interglaciation.
The sodium and potassium concentrations in leaf and stem have been genetically studied as physiological components of the vegetative and reproductive development in two populations of F₈ lines, ...derived from a salt sensitive genotype of Solanum lycopersicum cv. Cerasiforme, as female parent, and two salt tolerant lines, as male parents, from S. pimpinellifolium, the P population (142 lines), and S. cheesmaniae, the C population (116 lines). Genetic parameters of ten traits under salinity and five of them under control conditions were studied by ANOVA, correlation, principal component and QTL analysis to understand the global response of the plant. Two linkage maps including some tomato flowering time and salt tolerance candidate genes encoding for SlSOS1, SlSOS2, SlSOS3, LeNHX1, LeNHX3, were used for the QTL detection. Thirteen and 20 QTLs were detected under salinity in the P and C populations, respectively, and four under control conditions. Highly significant and contributing QTLs (over 40%) for the concentrations of Na⁺ and K⁺ in stems and leaves have been detected on chromosome 7 in both the populations. This is the only genomic position where the concentration QTLs for both the cations locate together. The proportion of QTLs significantly affected by salinity was larger in the P population (64.3%, including all QTLs detected under control) than in the C population (21.4%), where the estimated genetic component of variance was larger for most traits. A highly significant association between the leaf area and fruit yield under salinity was found only in the C population, which is supported by the location of QTLs for these traits in a common region of chromososome C1. As far as breeding for salt tolerance is concerned, only two sodium QTLs (lnc1.1 and lnc8.1) map in genomic regions of C1 and C8 where fruit yield QTLs are also located but in both the cases the profitable allele corresponds to the salt sensitive, cultivated species. One of those QTLs, lnc1.1 might involve LeNHX3.
Display omitted
•Grafting itself increased Na+ in the xylem sap under N-sufficient conditions.•Three QTLs governing LNC were common under contrasting N availabilities.•The wild allele increased LNC ...for most rootstock QTLs under N-sufficient conditions.•QTLs for rootstock-mediated N uptake efficiency were clustered in chromosome 9.•Three coding genes for nitrate transporters were found within LNC QTL intervals.
Selecting rootstocks for high nitrogen acquisition ability may allow decreased N fertilizer application without reducing tomato yields, minimizing environmental nitrate pollution. A commercial hybrid tomato variety was grafted on a genotyped population of 130 recombinant inbred lines (RILs) derived from Solanum pimpinellifolium, and compared with self- and non-grafted controls under contrasting nitrate availabilities (13.8 vs 1.0mM) in the nutrient solution.
Grafting itself altered xylem sap composition under N-sufficient conditions, particularly Na+ (8.75-fold increase) concentration. N deprivation decreased shoot dry weight by 72.7% across the grafted RIL population, and one RIL rootstock allowed higher total leaf N content than the best of controls, suggesting more effective N uptake.
Sixty-two significant QTLs were detected by multiple QTL mapping procedure for leaf N concentration (LNC), vegetative growth, and the xylem sap concentrations of Mn and four phytohormone groups (cytokinins, gibberellins, salicylic acid and jasmonic acid). Only three LNC QTLs could be common between nitrogen treatments. Clustering of rootstock QTLs controlling LNC, leaf dry weight and xylem sap salicylic acid concentration in chromosome 9 suggests a genetic relationship between this rootstock phytohormone and N uptake efficiency. Some functional candidate genes found within 2 Mbp intervals of LNC and hormone QTLs are discussed.
Salt tolerance has been analysed in two populations of F₇ lines developed from a salt sensitive genotype of Solanum lycopersicum var. cerasiforme, as female parent, and two salt tolerant lines, as ...male parents, from S. pimpinellifolium, the P population (142 lines), and S. cheesmaniae, the C population (116 lines). Salinity effects on 19 quantitative traits including fruit yield were investigated by correlation, principal component analysis, ANOVA and QTL analysis. A total of 153 and 124 markers were genotyped in the P and C populations, respectively. Some flowering time and salt tolerance candidate genes were included. Since most traits deviated from a normal distribution, results based on the Kruskal-Wallis non-parametric test were preferred. Interval mapping methodology and ANOVA were also used for QTL detection. Eight out of 15 QTLs at each population were detected for the target traits under both control and high salinity conditions, and among them, only average fruit weight (FW) and fruit number (FN) QTLs (fw1.1, fw2.1 and fn1.2) were detected in both populations. The individual contribution of QTLs were, in general, low. After leaf chloride concentration, flowering time is the trait most affected by salinity because different QTLs are detected and some of their QTLxE interactions have been found significant. Also reinforcing the interest on information provided by QTL analysis, it has been found that non-correlated traits may present QTL(s) that are associated with the same marker. A few salinity specific QTLs for fruit yield, not associated with detrimental effects, might be used to increase tomato salt tolerance. The beneficial allele at two of them, fw8.1 (in C) and tw8.1 (for total fruit weight in P) corresponds to the salt sensitive parent, suggesting that the effect of the genetic background is crucial to breed for wide adaptation using wild germplasm.
Cyprideis torosa is a species of ostracode that inhabits a wide range of aquatic habitats in which its low Alk/Ca requirement is met. Its fossil remains are widely used in palaeoecological studies of ...coastal environments and inland salt lakes. We collected C. torosa from 20 water bodies near Valencia, Spain. Temperature, chlorophyll a concentration, electrical conductivity, and the concentration of major ions and oxygen isotopes were measured at each site. Between 2 and 20 live individuals of C. torosa were collected per site, their instar stage and sex determined and their shell chemistry (Mg/Ca, Sr/Ca and carbon and oxygen isotope composition) analyzed. Three of these sites were sampled monthly for one year, and ostracode population structure and shell chemistry (20–40 shells) were analyzed. The water chemistry varied widely between sites. TDS (total dissolved solids) ranged from 0.5 to 71.8g/L but chloride was always the dominant anion.
There is a significant positive relationship between ostracode and water δ18O except at high TDS (>20g/L) when shell δ18O values are lower than expected. No effect of either temperature or water Mg/Ca is observed on the Mg/Ca in the ostracode calcite in waters with Mg/Ca<6 (molar ratio). Ostracode shell Sr/Ca is strongly and significantly related to water Sr/Ca. δ13C values in C. torosa shells are ∼2‰ lower than observed δ13CDIC. These results provide new and more accurate quantification tools to reconstruct past hydrochemistry from C. torosa shells.
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