Endogenous abscisic acid and 2-trans-abscisic acid in alternate bearing ‘Wilking’ mandarin trees

The relationship of abscisic acid (ABA) and 2-trans-abscisic acid (t-ABA) to alternate bearing has been examined in Wilking mandarin (Citrus reticulata Blanco) trees. Leaves, stems and buds of trees loaded with fruit (on trees) had 4.3, 6.0 and 2.2 fold higher ABA levels than the corresponding organs from off trees. Leaves had higher ABA levels than stems and buds in both on and off trees. t-ABA was non-detectable in Wilking leaf, stem and bud tissue. Amounts of t-ABA not exceeding 40% of the ABA content, were found in Shamouti and Valencia orange buds and in Wilking fruit peel.The elevated levels of ABA in on tree organs may reflect a stress imposed by the fruit overload.     

Genetic variation in the subunits of globulin-1 storage protein of French bean

Summary Charge and molecular weight heterogeneity of globulin-1 (G1) polypeptides of the bean, Phaseolus vulgaris L., were revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Different bean cultivars were classified into three groups: Tendergreen, Sanilac, and Contender on the basis of their protein subunit composition. Nine distinct major bands: 51,49, 48.5,48^T, 48^S, 47, 45.5, 45^S, and 45^C, and two minor bands: 46^T and 46^S were found to account for the three profiles seen on one-dimensional SDS-PAGE. Two-dimensional analysis revealed these eleven protein bands to be composed of a minimum of fourteen distinct protein subunits. The Tendergreen and Sanilac types differ in their G1 polypeptide composition. The protein patterns of the Contender types are intermediate, containing many protein subunits found in the patterns of the Tendergreen and Sanilac types suggesting a genetic and evolutionary relationship.     

Genotypic variation in the germination of common bean in response to cold temperature stress

Beans (Phaseolus vulgaris) are regarded as a susceptible crop to suboptimal temperatures. In temperate regions, low temperatures reduce establishment of beans when planted early in the growing season. Seeds of 14 cultivars/lines or beans were germinated in petri dishes at a constant 8, 10, 12, or 18°C or at 12 h alternating temperatures of 10/8, 12/8 or 18/8°C. Differences in germination percentages and rates between cultivars/lines were significant, especially at low temperatures. Cultivars/lines that germinated best and quickly at constant 8°C were Volare, Great Northern (G.N.) Tara, G.N. Belneb # 1, G.N. Spinel, and San Cristobal. Germination percent and rate of Pinto-UI-111 and Canadian Wonder increased significantly when temperatures were increased by 2 to 4°C for 12 h per 24 h, compared with a constant 8°C. Whereas, germination of G.N. Belneb # 1 was reduced. Polyacrylamide gel electrophoresis was used to study the effect of cold treatment on polypeptide patterns of seven cultivars/lines. Seeds were germinated at 18°C constant for 96 h or at 18°C for 48 h followed by 48 h at 2 or 8°C. During cold treatment the synthesis of some polypeptides increased. Volare, G.N. Tara Pinto-UI-111 and Canadian Wonder showed changes in polypeptide patterns, while Alubia-33-1, Michigan 84100 and BAT-1225 showed no changes in polypeptide patterns if compared to the control (96 h at 18°C in the dark). This suggests a likely essential role of these proteins in the development of chilling tolerance.     

High-level Expression of Maize <Emphasis Type="Italic">γ</Emphasis>-zein Protein in Transgenic Soybean (<Emphasis Type="Italic">Glycine max</Emphasis>)

Primers were developed for 118 microsatellites isolated from grape (Vitis vinifera) genomic libraries enriched for (AC)n repeats. Only one microsatellite sequence matched other grape SSR-sequences in the GeneBank database. Genotyping was carried out in the parental lines and four offspring of two pseudo-test-cross populations, Cabernet Sauvignon x Seyval and Chardonnay x Bianca, and a further six other grape genotypes (V. vinifera Sultanina, Merlot, Syrah, Müller-Thurgau, Vitis Regent and V. riparia Gloire de Montpellier). A total of 108 microsatellites showed easily scorable alleles and 100 of them segregated according to a configuration suitable for mapping in either cross. A further 8 SSRs, although unsuitable for mapping in those crosses, showed polymorphism in the other genotypes tested. This set of markers was used, along with 75 microsatellites of other repeat-types, to fingerprint 46 offspring of the cross Chardonnay x Bianca. For each full-sib, individual heterozygosity and distance in repeat units between pairs of alleles at each locus (mean d²) were calculated as a tool for predicting highly outbred recombinant individuals. Six microsatellites with segregation ratios significantly distorted towards the lack of homozygous sibs were identified and mapped to linkage groups LG 3 and LG 5. Estimation of heterozygosity at genome-wide level and genotyping at loci for which homozygous sibs are discriminated against are discussed for marker-assisted background selection in outcrossing grapevines.     

Genetic analysis of two wheat cultivars, ‘Sonalika’ and ‘WL 711’ for reaction to leaf rust (Puccinia recondita)

Summary Genetic analysis for leaf rust reaction of two widely adapted cultivars, Sonalika and WL 711, has been done using 21 near isogenic Lr lines and rust culture IL004 — avirulent on the two cultivars and all the Lr lines used. The segregation pattern in the F₂ generation indicated the presence of a recessive gene in Sonalika and of a dominant gene in WL 711. These genes in cultivars Sonalika and WL 711 have been identified as Lr 11 and Lr 13, respectively. Gene Lr 13 is no longer effective in WL 711 but it continues to give field resistance in the backgrounds of Chris, Prelude and Thatcher. There has been no significant change in the virulence spectrum of the leaf rust pathogen in India with the release of WL 711. High susceptibility of WL 711 seems to be due to the evolution of more aggressive forms of the pathogen to this cultivar. The gene Lr 11, which behaves as a recessive in Sonalika, was effective against leaf rust when this cultivar was released. The high susceptibility of Sonalika is probably due to an increase in the frequency of race 77 virulent on Lr 11. Lr 11 has shown a dominance reversal in the background of Sonalika. Present results suggest that interaction of resistance genes with the background genotype must be studied for their effective use in breeding programme.     

Identification of two RAPD markers tightly linked with the Nicotiana debneyi gene for resistance to black root rot of tobacco

Linkage of randomly amplified polymorphic DNA (RAPD) markers with a single dominant gene for resistance to black root rot (Chalara elegans Nag Raj and Kendrick; Syn. Thielaviopsis basicola [Berk. and Broome] Ferraris) of tobacco (Nicotiana tabacum L.), which was transferred from N. debneyi Domin, was investigated in this study. There were 2594 repeatable RAPD fragments generated by 441 primers on DNAs of Delgold tobacco, a BC₅F₈ near isogenic line (NIL) carrying the resistance gene in a Delgold background, and PB19, the donor parent of the resistance gene. Only 7 of these primers produced eight RAPD markers polymorphic between Delgold and PB19, indicating there are few RAPD polymorphisms between them despite relatively dissimilar pedigrees. Five of the eight RAPD markers were not polymorphic between Delgold and the NIL. All of these markers proved to be unlinked with the resistance gene in F₂ linkage tests. Of the remaining three RAPD markers polymorphic between Delgold and the NIL, two were shown to be strongly linked with the resistance gene; one in coupling and the other in repulsion. Application of the two RAPDs in the elimination of linkage drag associated with the N. debneyi resistance gene and marker-assisted selection for the breeding of new tobacco cultivars with the resistance gene is discussed.     

Uptake of Zn++ and aflatoxin from perlite and liquid culture by Zea mays seedlings

The present paper reports our attempts to determine whether the inclusion of 0.0014 mM Zn⁺⁺ within a hydroponic culture medium affects the ability of 12-day-old Zea mays, cv. SS-522 to take-up [³H]-aflatoxin B₁. Data from the corollary experiment, i.e., whether inclusion of aflatoxin affects the ability of Zea mays, cvs. Truckers White, X-Sweet and Merit to take-up ⁶⁵ZnCl₂ are presented also. This report is a preliminary to one regarding an in-progress analysis of whether pollutant levels of Zn⁺⁺ affect aflatoxin uptake and distribution. In the absence of irrigating seedlings, which were grown in Perlite containing ⁶⁵ZnCl₂, with a solution containing mixed aflatoxins, the stem contained the greatest amount of label with root plus seed the next highest and the leaf the least for each of the cvs. In contrast, when the seedlings were irrigated with a solution containing mixed aflatoxins, the root plus seed contained either an amount nearly identical to (cv. Truckers White) or in excess of that within the stem (cvs. X-Sweet and Merit). Calculation of the percentages of aflatoxin-induced diminutions in leaf, stem and root label suggested that the aflatoxins interfered with the translocation of ⁶⁵ZnCl₂ from the root to the stem and leaf, at least for cvs X-Sweet and Merit. When 0.0014mM Zn⁺⁺ as ZnSO₄ was added to an incubation medium in which 12-day-old seedlings were suspended and plant growth assessed over 72 hours, a 15% increase (significant at 0.05 level) in seedling height over that of Zn⁺⁺-deficient plants was observed. No differences in [³H]-aflatoxin B₁ uptake were noted between those seedlings which were grown in either Zn⁺⁺-containing or lacking media. Less than one % of the[³H]-aflatoxin B₁ which was taken-up was recovered within chloroform extracts of the seedlings. The distributions of radioactivity from [³H]-aflatoxin B₁ for leaf, stem, seed and root were 0, 57, 26 and 19% and 0, 26, 58 and 18% for Zn⁺⁺-containing and -lacking media, respectively.     

The inheritance of host plant resistance and its effect on the relative infection efficiency of Magnaporthe grisea in rice cultivars

The inheritance of host plant resistance and its effect on the relative infection efficiency for leaf blast was studied in the crosses IR36/CO39 (partially resistant × highly susceptible) and IR36/IR64 (both partially resistant). On the natural scale, gene action appeared multiplicative. After log transformation, additive effects described most of the genetic variation in the cross IR36/CO39, while additive and dominance effects were about equal in magnitude in the cross IR36/IR64. Dominance was towards increased resistance. No transgressive segregation occurred in the cross IR36/CO39. The number of genes that reduce lesion number was estimated to be zero in CO39 and five or more in IR36. The cross IR36/IR64 showed transgressive segregation in both directions, and IR36 and IR64 each contain at least one gene that is not present in the other cultivar. The heritabilities (narrow sense) in the F₂ were low (range 0.06–0.16), while narrow sense heritabilities based on F₃ lines were much higher (range 0.41–0.68). Lesion numbers in F₃ lines were reasonably correlated with those in F₅ progenies derived from the same F₂ plant (r was±0.6 in both crosses). Partial resistance can be effectively improved by selecting the most resistant plants from the most resistant F₃ lines.     

Heterosis among populations of maize (Zea mays L.) with different levels of exotic germplasm

Summary Thirteen maize (Zea mays L.) populations including five adapted, five adapted x exotic, two composites of adapted and exotic, and one exotic selected for adaptability were crossed in a diallel mating system. The parents and 78 crosses and nine check hybrids were evaluated for grain yield and plant height in five environments. The Gardner-Eberhart model Analysis II indicated that additive and nonadditive gene effects accounted for 60 and 40% of the total variation among populations, respectively, for grain yield and 86% and 14% of the total variation, respectively, for plant height. Components of heterosis were significant in the combined analysis for both traits. Adapted Corn Belt populations tended to have higher performance in crosses and greater values of variety heterosis than 50% adapted populations. Nebraska Elite Composite, Corn Belt x Mexican, and Corn Belt x Brazilian showed high mean yields in crosses, however, they were not among those with high estimates of variety heterosis. One exotic population (Tuxpeno x Antigua Grupo 2) and three adapted populations [307 Composite, NB(S₁)C-3, and NK(S₁)C-3] might be combined together to form a high-yielding population. It may be possible to synthesize two useful populations for reciprocal recurrent selection by grouping Tuxpeno x Antiqua Grupo 2, NB(S₁)C-3, and NS(FS)LFW-8 into one population and NK(S₁)C-3, KrugxTabloncillo, and 307 Composite in the other one.Contribution from the Department of Agronomy, University of Nebraska, Lincoln, NE 68583. Published as Paper No. 8011. Journal Series, Nebr. Agric. Exp. Station. Research was conducted under Project 12-049     

Comparative study on the chloroplast,mitochondrial and nuclear genome differentiation in two cultivated rice species,Oryza sativa and O. glaberrima,by RFLP analyses

Summary Restriction fragment length polymorphisms of chloroplast (ct), mitochondrial (mt) and nuclear DNA were investigated using eight cultivars of Oryza sativa and two cultivars of O. glaberrima. Relative variability in the nuclear and cytoplasmic genomes was estimated by a common measure, genetic distance. Based on the average genetic distances among ten cultivars for each genome, the evolutionary variabilities of the mitochondrial and nuclear genomes were found to be almost the same, whereas the variability of the chloroplast genome was less than half that of the other two genomes. Cluster analyses on ct and mt DNA variations revealed that chloroplast and mitochondrial genomes were conservative within a taxon and that their differentiations were well-paralleled with respect to each other. For nuclear DNA variation, an array of different degrees of differentiation was observed in O. sativa, in contrast with little variation in O. glaberrima. As a whole, differentiation between O. sativa and O. glaberrima was clearly observed in all three genomes. In O. sativa, no notable difference was found between the cultivars Japonica and Javanica, whereas a large differentiation was noticed between Japonica (including Javanica) and Indica. In all three genomes, the average genetic distances within Indica were much larger than those within Japonica (including Javanica), and almost similar between Japonica (including Javanica) and Indica. These facts indicate that differentiation in O. sativa was due mainly to Indica.     

Wheat chromosome 2D carries genes controlling the activity of two DNA-degrading enzymes

DNA-degrading enzymes of 24.0 kDa and 27.0 kDa were observed to have different activities in two common wheat (Triticum aestivum L.) cultivars, Wichita and Cheyenne. A substrate-based SDS-PAGE assay revealed that these two enzymes were much more active in Wichita than in Cheyenne. Genes controlling the activities of these two enzymes were localized on chromosome 2D by testing DNA-degrading activities in reciprocal chromosome substitution lines between Wichita and Cheyenne. While the allele on Wichita chromosome 2D stimulated the activities of the 24.0- and 27.0-kDa enzymes in Cheyenne, the allele on Cheyenne chromosome 2D did not reduce the activities of the 24-kDa and 27-kDa enzymes in Wichita. Whether these genes code for the DNA-degrading enzymes themselves or for factors that regulate the enzyme activities remains unknown.This work was supported in part by USDA-Competitive Research Grants Office grant No. 90-37140-5426 to P.S.B. Contribution from Agricultural Research Division, University of Nebraska. Journal Series Number 10304     

Mutagenic effectiveness and efficiency of EMS,DES and gamma-rays in rice

Summary Data on chlorophyll mutation frequency after treatment with EMS, DES and gamma-rays and sequential administration of gamma-rays and the two alkylating agents in three varieties of rice have been used to work out quantitatively the effectiveness and efficiency of each mutagen and combination treatment. For effectiveness, the order is EMS > DES and for efficiency it is EMS > DES > gamma-rays. In some sequential treatments (Gamma-rays + DES in IR8 and Basmati; DES + gamma-rays in IR8 and Jhona; Gamma-rays + EMS in IR8 and Basmati; and EMS + gamma-rays in IR8, Jhona and Basmati) mutation frequency is more than additive (synergistic) but these treatments are decisively less efficient because of their relatively high injurious effects in the M₁. generation. EMS induces more albinas than gamma-rays do. The mutational spectrum patterns induced by gamma-rays and DES are alike. In general, combination treatments tend to increase the frequency of albinas over other types of chlorophyll mutants.     

Monosomic analysis of heading date and spikelet number in the common wheat (Triticum aestivum L.) multispikelet line ‘Noa’

Summary Genetic analysis of heading date and spikelet number was carried out in the common wheat (Triticum aestivum L.) multispikelet line Noa, by using the monosomic series of the regular line Mara. Noa's high number of spikelets was found to be controlled by a recessive major gene on chromosome 2D; a slight reduction in spikelet number was induced by another recessive gene on Noa's 7A chromosome. Noa's late heading date was found to be controlled by two recessive genes, located on chromosome 2D (a major effect) and 6B (a minor effect). The nature of the genes located on Noa's 2D chromosome and the relationship between spikelet number and heading date are discussed.     

The final thermal preferendum of fishes: Shuttling behavior and acclimation overshoot

The concept of final preferendum is reexamined in light of data concerning acclimation in a cyclic thermal regime. Because of Shuttling behavior to temperatures above and below the mean preferendum, and because of faster acclimation upward than downward, which result in acclimation to a temperature exceeding the mean of the cycle, a fish may finally gravitate to a preferendum which does not equal acclimation temperature. It is suggested that a distinction be made between the crossover-point preferendum, where preference and acclimation are equal, and the ultimate preferendum to which a fish will ultimately gravitate.     

Directional components derived from initial-orientation data of inexperienced homing pigeons

Summary 1,324 vanishing bearings of individual pigeons, completely inexperienced in homing, were recorded during 100 releases at 36 sites symmetrically distributed around their home loft near Würzburg at distances ranging from 7 to 180 km. Two directional components could be derived from the data: (a) a weak but significant homeward component pointing to the loft site and (b) a more pronounced compass component pointing to the northwest (Fig. 1). With the latter kind of tendency the pigeons clearly demonstrated what earlier had been described as preferred compass direction (PCD).Homeward directedness at the 36 differently situated release sites is negatively correlated with angular divergence between PCD and homeward direction (Fig. 2). Compass preferences derived from different quartets of symmetrically arranged sites were similar. Over a period of 11 years the PCD varied significantly in time but did not change fundamentally (Figs. 3, 4). Interrelations between various parameters of initial-orientation data were investigated by correlation analyses (Table 3).PCDs have not only been found in the Würzburg area but around many other loft sites as well. They are, however, differently pronounced, and in experienced pigeons they are generally weaker than in first-flight birds. Various reasons (partly evident, partly thought possible) for variability of PCDs, and for their absence in some series of experiments, are discussed.As a PCD persists, and even tends to become clearer, after elimination of homeward orientation by olfactory deprivation, it is concluded that it reflects directional tendencies which are independent of the process of site localization. A great deal of what is called release-site biases, i.e., site-specific deviations from the beeline course towards home, can be understood on a PCD basis. The functional background of the PCD is unknown. Hypothetical advantages for the pigeons homing strategy are considered.Abbreviations RSB release-site bias - PCD preferred compass direction     

Thidiazuron substitution for chilling requirement in three apple cultivars

Thidiazuron [(TDZ)N-phenyl-N-1,2,3-thidiazol-5-ylurea] at 750 M was applied to buds of apple trees to determine if it could substitute for the chilling requirement to induce bud break. Shoots of cv. Anna (low chill), Delicious cv. Redchief (medium chill), and Northern Spy (high chill) were untreated, treated with TDZ prior to chilling (before-chill), and treated with TDZ at various intervals after the accumulation of specific amounts of chilling (after-chill). Shoots were stored in a cold room at 4°C. TDZ applied prior to chilling reduced the chill unit (CU) requirement (1 CU = 1 h at 4°C) for the promotion of bud break on 1-year-old shoots of Anna and Northern Spy and 1- and 2-year-old wood of Delicious. TDZ applied after-chill promoted bud break only for Anna and buds on 2-year-old wood of Delicious. While accumulating CUs, untreated buds or buds treated with TDZ on 1-year Delicious and Northern Spy did not respond to the cold treatment even after 1848 h of CU accumulation. For all three cultivars, TDZ treatment was more effective in promoting bud break when applied before the initiation of chilling.The use of a company or product name does not constitute an endorsement by USDA or the University of Maryland nor imply approval to the exclusion of other suitable products.     

Synthesis of hexaploid (AABBCC) somatic hybrids: a bridging material for transfer of ‘tour’ cytoplasmic male sterility to different Brassica species

Most of the alloplasmic cytoplasmic male sterility (CMS) systems are known to be associated with a number of floral abnormalities that result from nuclear-cytoplasmic incompatibilities. One such system, tour, which is derived from Brassica tournefortii, induces additional floral abnormalities and causes chlorosis in Brassica spp. While the restorer for this CMS has been reported to be present in B. napus, in B. juncea, where the abnormalities are more pronounced, no restorer has yet been identified. Rectification of these floral abnormalities through mitochondrial recombinations and chloroplast replacement might result in the improvement of this CMS system. As organelle recombinations can possibly be achieved only by somatic cell hybridization, fusion experiments were carried out between hygromycin-resistant B. juncea AABB carrying tour cytoplasm and phosphinotricin-resistant, normal B. oleracea CC to generate AABBCC hexaploid somatic hybrids. The presence of selectable marker genes facilitated the selection of hybrids in large numbers. The resulting hybrids showed wide variation in floral morphology and organelle composition. Regenerants with normal, male-sterile flowers having recombinant tour-or oleracea-type mitochondria and oleracea-type chloroplasts were obtained. Hybrids with male-fertile flowers were also obtained that had recombined tour mitochondria. The AABBCC hexaploid hybrids synthesized in the present study were successfully utilized as a bridging material for transferring variability in the organelle genome simultaneously to all the digenomic Brassica species, and all of these hybrids are now being stabilized through repeated backcrosses to the allopolyploid crop brassicas.     

Variation in the karyotype of three cultivars of Narcissus tazetta L. (Amaryllidaceae)

Three cultivated varieties of Narcissus tazetta, Grand Soleil d'Or, Chinese Sacred Lily and Cypri, are triploid (2n = 3x+30) with the basic number 10. Grand Soleil d'Or has three homomorphic sets, each comprising 2 long submetacentrics, 4 long acrocentrics and 4 short acrocentrics. Karyotypes of the other two varieties are heteromorphic. Both possess one telocentric satellited chromosome. In addition, Cypri shows translocation between two chromosomes belonging to the seventh and eighth triplets. The number of secondary constrictions varies between 3 (Chinese Sacred Lily) and 4 (Grand Soleil d'Or and Cypri) which is also the number of nucleoli observed in the respective varieties.     

For Doctors‘ Eyes Only: Medical Records in Two Israeli Hospitals

Scientific and craft representations of medicaldiagnosis can be regarded as complementary discursivesystems used by physicians in order to legitimate andmonopolize their professional power. This paperexamines the medical record as a context for theinterplay of these two discourses. During interviewsconducted with 78 Israeli physicians, 94% haverefused to give patients access to their medicalrecords. This refusal is discussed vis-à-vis a readingof the actual contents of medical records, which areshown to contain many errors, inconsistencies andambiguities. The paper concludes by offering analternative, anthropological model for medical recordsas fieldnotes.     

Regeneration strategy of mangroves along the Kenya coast: a first approach

In June 1990 a research project sponsored by DANIDA and AWF was carried out by botany students of Nairobi University to investigate the regeneration strategy of mangroves at Gazi bay and Mida creek. Statistical analysis of 449 quadrats (5 × 5 m) sampled along 35 line transects in 4 mangrove forests showed that mangrove seedlings follow the same distribution pattern in the intertidal zone as their parent trees. In other words, mangrove seedlings mainly develop within a well-defined species specific zone. These distribution zones for the various mangrove trees and their seedlings are defined in terms of elevation above the mean low water level of spring tides.Through assigning mangrove seedlings in the intertidal zone to the categories (i) fixed or not-fixed, and (ii) covered or not-covered, evidence was found that propagule dispersal followed both the self-planting theory and the stranding theory. The self-planting theory appeared to be the major mechanism of propagule dispersal in undisturbed mangrove forests, whilst the stranding theory proved to be predominant in colonizing over-exploited and cleared mangrove forests.It is concluded that re-afforestation of mangrove seedlings in the intertidal zone will be most successful when the seedlings are planted in their specific distribution zones under fixed conditions.