Factorial regression analysis of genotype by environment interaction in ryegrass populations, using both isozyme and climatic data as covariates

A sample of 58 natural ryegrass populations (Lolium perenne L.) from the French and Spanish oceanic coast was evaluated for three seasonal growth traits (i.e. spring, autumn and winter vigour traits) in 5 evaluation sites (three in France and two in Spain). This sample showed a high level of genotype (population) × environment (evaluation sites) interactions for the three agronomic traits. A factor regression analysis, using both isozyme frequencies of populations and climatic factors of evaluation sites as covariates, was carried out on a sub-sample of 30 populations in order to explain these interactions. This method succeeded in explaining most population × location interactions by the product of two covariates. For instance, for spring vigour trait, 72.8% of the interaction term could be explained by the use of two covariates: the PGI2-20 allelic frequency of populations and the minimum temperature of the coldest month of evaluation sites. This study shows the advantage of such a method for plant breeders who need to identify promising ryegrass populations for their breeding objectives. A number of genetic and evolutionary hypotheses are also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Allelic variation in linolenic acid content of high erucic acid Ethiopian mustard and incorporation of the low linolenic acid trait into zero erucic acid germplasm

Zero erucic acid germplasm of Ethiopian mustard is characterized by high levels of linolenic acid (about 21%). Two genetic sources of low linolenic acid (N2‐4961 and HF‐186, about 5%), have been developed in a high erucic acid background. The objectives of this research were to study the genetic relationship between the two low linolenic acid lines and to transfer the trait to zero erucic acid germplasm. F1 seed generations from crosses between both lines had higher average linolenic acid concentration than both parents. F2 seeds segregated for linolenic acid content following a continuous variation from 1.8 to 7.4%, exceeding the limits of the parental distribution ranges. Transgressive recombinants with very low linolenic acid concentration (0.7‐2.7%) were confirmed in the F3 seed generation. The results suggested that N2‐4961 and HF‐186 possess alleles for low linolenic acid at different loci. Transgressive low linolenic acid F3 plants were crossed with plants of a zero erucic acid line and a selection for zero erucic, low linolenic acid was conducted. As a result, a zero erucic acid F3:4 line containing 1.5 ± 0.7% linolenic acid was developed.     

Genetic characterization of banana cultivars (Musa spp.) from Brazil using microsatellite markers

Flavonoids, in particular the anthocyanins,are responsible for flower colour in manyspecies. The dihydroflavonols represent abranch point in flavonoid biosynthesis,being the intermediates for production ofboth the coloured anthocyanins, through theaction of the enzyme dihydroflavonol4-reductase (DFR), and the colourlessflavonols, produced by flavonol synthase(FLS). In this study the white-flowered,flavonol accumulating Mitchell line ofpetunia was used as a model to examine theinteraction between DFR and FLS enzymeactivities and possibilities forredirecting flavonoid biosynthesis awayfrom production of flavonols and towardsanthocyanins. Introduction of a 35SCaMV-DFR sense transgene construct causedthe production of anthocyanins, resultingin a pink-flowered phenotype. Furthermore,inhibition of FLS production throughintroduction of an FLS antisense RNAconstruct also led to anthocyaninproduction and a pink-flowered phenotype. A combination of both transgenes gave thehighest level of anthocyanin formation. Anthocyanins were produced in the DFR-senseand FLS-antisense transgenic lines in spiteof the greatly reduced levels of geneexpression in the Mitchell line for threeenzymes late in anthocyanin biosynthesis,anthocyanindin synthase, UDP-glucose:flavonoid 3-O-glucosyltransferase andUDP-rhamnose: anthocyanidin-3-glucosiderhamnosyltransferase. Thus, the level ofgene activity required for visibleanthocyanin formation is much lower thanthe high levels normally induced duringpetal development. Altering the balancebetween the DFR and FLS enzyme activities,using genetic modification, may be a usefulstrategy for introducing or increasinganthocyanin production in target ornamentalspecies.     

Relationships among American and Spanish populations of maize

Summary Two experiments were carried out with two objectives. First, to establish the phenetic relationships among the maize (Zea mays L.) landraces from Galicia (Northwestern Spain) maintained at the Misión Biológica de Galicia. Second, to assess the resemblance between a collection of Spanish populations (including the landraces from Galicia) and a set of US Corn Belt varieties. For the first objective 73 varieties from Galicia, along with 9 hybrid checks, were grown in 9×9 simple lattices at two locations for two years. For the second objective 131 populations from the US Corn Belt and Spain, along with 9 hybrid checks, were grown for three years in unreplicated experiments. Cluster analyses were carried out with the first principal components that accounted for a significant amount of the total variation. Four groups were found among the landraces from Galicia. The populations from Spain and America were classified as belonging to nine main groups. The replicated experiment was more accurate than the unreplicated one. However, it is concluded that an unreplicated test grown in several environments is accurate enough to detect the main groups, although some inaccuracies should be expected.     

Cytological studies on adventitious shoots and minitubers of a monoploid potato clone

Summary A three step procedure for adventitious shoot regeneration on leaf explants of monoploid potato clone H7322 and a minituber induction procedure on stem segments have been described. Chromosome counts on 92 adventitious shoots showed that 85% of them had been polyploidized, i.e., 71% were diploid, 1% tetraploid, and 13% were mixoploid. Cytophotometric studies on nuclei of soil grown tubers of tetraploid cv Astarte, of 1x, 2x and 4x adventitious shoots of H7322, and of diploid H²578 showed in all cases polyploidization with prominent classes up to 8C and 16C. However, nuclei of pith cells of 5 weeks old minitubers which had developed on monoploid H7322 itself or on 1x adventitious shoots of H7322 showed predominantly 1C and 2C values. Pith cells of minitubers of monoploid H7322 were screened, after iodine staining, for the presence of variant cells containing reddish-brown staining (amylose-free) starch. In more than 75% of the investigated minitubers one or a few of such variant cells were found indicating that such a variation occurs in minitubers of monoploid potato and that this variant character is expressed in cells of vegetative storage organs like potato tubers.     

Effect of heated sunflower oil and dietary supplements on the composition, oxidative stability, and sensory quality of dark chicken meat

A factorial design was used to study the effect of dietary oxidized sunflower oils (fresh, heated at low temperatures, and heated at high temperatures), DL-alpha-tocopheryl acetate (0 or 100 mg/kg), and Zn supplementation (0 or 600 mg/kg) on the composition, oxidative stability, and sensory quality of dark chicken meat with skin from animals fed with a Se supplement (Se-enriched yeast, 0.6 mg of Se/kg). The positional and geometrical isomers of linoleic acid were increased in raw meat from chickens fed oils oxidized at high temperatures. In addition, supplementation with alpha-tocopheryl acetate increased the alpha-tocopherol content, whereas 2-thiobarbituric acid (TBA) values and lipid hydroperoxide content were reduced. Likewise, TBA values, rancid aroma, and rancid flavor also decreased in cooked dark meat. However, none of the dietary factors studied affected consumer acceptability scores of cooked meat. Furthermore, Zn supplementation increased the Se content in raw meat.     

Comparative analysis of tobacco-specific nitrosamines and total N-nitroso compounds in moldovan cigarette tobacco

While previous studies have evaluated levels of tobacco-specific nitrosamines (TSNA) and total N-nitroso compounds (NOC) in tobacco, there are no reports in the literature on TSNA and total NOC in the same tobacco products. We compared levels of TSNA, total NOC, and NOC precursors (NOCP) in tobacco of cigarettes purchased in Moldova and in some tobacco types commonly used for the manufacturing of Moldovan cigarettes. Cigarette tobaccos included those from non-Moldovan, traditional Moldovan, and blended Moldovan cigarettes. The results demonstrate that tobacco of non-Moldovan cigarettes contains higher TSNA and NOC levels (mean, 16 and 63 nmol/g tobacco, n = 6) than that of Moldovan cigarettes (mean, 5 and 23 nmol/g tobacco, n = 25). TSNA and NOC levels were also generally higher in tobacco of blended than in traditional Moldovan cigarettes. NOCP levels in Moldovan and non-Moldovan cigarette tobacco were similar as follows: 29000 +/- 30000 and 33000 +/- 28000 nmol/g tobacco (mean +/- SD). Total NOC were strongly correlated with total TSNA levels (r = 0.66; P < 0.0001). These findings demonstrate that current technologies involved in the manufacture of some blended cigarettes create conditions that favor N-nitrosation of alkaloids and other tobacco constituents.     

Lipid composition of lees from Sherry wine

In this paper, we describe the study and characterization of the lipids from lees of Sherry wine, one of the main byproducts from the wine-making industry in the Jerez/Xeres/Sherry denomination of the origin zone in Jerez de la Frontera, Spain. The lipid content, extractability, classification, fatty acid composition, and its main chemical characteristics have been determined in order to evaluate their potential use as a food or food additive.     

Plant nutrients in a degraded soil treated with water treatment sludge and cultivated with grasses and leguminous plants

The objective of this work was to evaluate rates for applications of water treatment sludge (WTS) as a nutrient source for grasses and leguminous plants cropped in a soil degraded by tin mining in the Amazon Region (Natural Forest of Jamari, Rondonia State, Brazil). The treatments consisted of three rates of nitrogen supplied by WTS (100, 150 and 200 mg kg⁻¹ soil), five combinations of plants, two controls (absolute control, without fertilization; and chemical control, soil+lime+chemical fertilizers). WTS modified the contents of macro and micronutrients in the degraded soil, but it was not, as used in the present study, sufficient for the rehabilitation of the degraded area.