Natural selection of allozyme polymorphisms: a microgeographic climatic differentiation in wild emmer wheat (Triticum dicoccoides)

Summary Allozymic variation in proteins encoded by 48 loci was analyzed electrophoretically in 1984 and 1985 in 137 individual plants of wild emmer wheat, Triticum dicoccoides, from a microsite in Yehudiyya, northeast of the Lake of Galilee, Israel. The test involved two climatic microniches in the open Tabor oak forest (1) sunny between trees and (2) shady under trees' canopies. Significant genetic differentiation at single-, two- and multilocus structures was found between neighboring climatic niches, which were only separated by a few meters. Our results suggest that allozyme polymorphisms in wild emmer wheat are partly adaptive, and differentiate primarily at the multilocus level by climatic factors presumably related to aridity stress.     

In situ hybridization as a rapid means to assess meiotic pairing and detection of alien DNA transfers in interphase cells of wide crosses involving wheat and rye

Summary The objectives of this study were to determine if biotin-labelled total genomic DNA of rye (Secale cereale L.) could be used to (i) preferentially label rye meiotic chromosomes in triticale and (ii) detect translocation stocks at interphase and/or early prophase by in situ hybridization. Welsh triticale, a wheat-rye segmental amphiploid, and Kavkaz wheat, a wheat-rye translocation were used. The results indicated that labelled chromosomes of rye and unlabelled chromosomes of wheat could be observed throughout all meiotic stages in the triticale. For Kavkaz wheat, the presence of the translocated 1RS chromosome arm of rye was detected at the interphase or very early prophase stage. Rapid assessment of feasibility of gene transfers and detection of alien DNA in somatic cells at the interphase stage by in situ hybridization allows for rapid decision-making and saves time and expense in plant breeding programs.Plant Research Centre Contribution No. 1276     

In vitro culture of the strobilar stage of Echinococcus granulosus from protoscoleces of human, camel, cattle, sheep and goat origin from Kenya and buffalo origin from India

Protoscoleces from human, camel, cattle, sheep, goat (all from Kenya) and buffalo (from India) hydatid cysts were cultured under identical conditions in vitro using the diphasic culture system of Smyth (1979b). Organisms from all sources grew and segmented in culture. Genital anlagen developed in all cultured worms but further genital differentiation occurred only in cultures of cattle (testes) and camel (testes and genital pore) material. The possible significance of these results is discussed in relation to the general epidemiology of hydatid disease and the potential infectivity of the different strains to man.     

Blood typing invalidates alleged evidence of fertility of XO mare

A mare with XO gonadal dysgenesis was reported to have produced two foals. Blood samples from the mare, her two foals, their sire and the mare's sire were typed for blood-group and serum protein variants in conjunction with registry requirements. Both foals qualified as offspring of the reported parents. However, the blood-typed mare could be excluded as an offspring of her alleged sire. An alternative hypothesis to explain the blood-type and karyotype findings was that a fertile mare had been substituted for the XO mare, as surrogate mother and blood-type donor. A computer search of 120,000 blood-type records identified only one other horse with the same blood type as the dam of the foals. That horse was a mare of the same breed and owned by the person who had attempted to register foals from the XO mare. These blood-type findings invalidated the allegation of XO fertility and emphasize the need for parentage verification to support reports of unusual reproductive performance.     

Resistance of wild wheat to stripe rust: Predictive method by ecology and allozyme genotypes

From 114 accessions of wild emmer wheat from 11 sites in Israel, known for their allozymic variation (Nevo & al. 1982), individual genotypes were tested for resistance to one isolate of stripe rust both in the seedling stage in a growth chamber and in the adult plant stage in the field. The results indicate that resistance to stripe rust in seedlings and adults are significantly correlated (r_s = 0.40, p < 0.001). Genetic polymorphisms of resistance to stripe rust vary geographically and are predictable by climatic, as well as allozymic markers. Three variable combinations of rainfall, evaporation, and temperature explain significantly 0.40–0.53 of the spatial variance in disease resistance to stripe rust, suggesting the operation of natural selection. Several allozyme genotypes are significantly associated with disease resistance. We conclude that natural populations of wild emmer wheat in Israel contain large amounts of disease resistance genes. These populations could be effectively screened and then utilized by the phytopathologist for identifying resistant genotypes and producing new resistant cultivars.Patterns of Resistance of Wild Wheat to Pathogens in Israel II.     

野生大豆基因文库的构建

以氯化铯密度梯度离心法纯化噬菌体λEMBL4,将纯化的EMBL4 DNA用BamH1/SalI双酶切制成载体。用CTAB(十六烷基三甲基溴化铵)法提取野生大豆(种名待定)大分子DNA,Sau3A部分酶解,从琼脂糖凝胶中回收10—22kb“目的”DNA片段,与载体连接,体外包装成重组噬菌体。所得重组子值为8×10(?)pfu(噬菌斑形成单位),达到了构建野生大豆基因文库要求的理论值。以栽培大豆7S贮藏蛋白a′-cDNA作探针,用噬菌斑原位杂交法从文库中筛选出一个阳性克隆。     

Genome size in wild Pisum species

Genome size was measured in 75 samples of the wild pea species Pisum abyssinicum, P. elatius, P. fulvum and P. humile by ethidium-bromide (EB) flow cytometry (internal standard: Triticum monococcum) and Feulgen densitometry (internal standard: Pisum sativum Kleine Rheinländerin). Total variation of EB-DNA between samples covered 97.7% to 114.9% of the P. sativum value, and Feulgen DNA values were strongly correlated with EB-DNA values (r=0.9317, P < 0.001). Only P. fulvum was homogeneous in genome size (108.9% of P. sativum). Wide variation was observed between samples in P. abyssinicum (100.9–109.7%), P. elatius (97.7–114.9%) and P. humile (98.3–111.1% of P. sativum). In view of the world-wide genome size constancy in P. sativum, the present data are interpreted to show that the pea taxa with variable genome size are genetically inhomogeneous and that the current classification is not sufficient to describe the biological species groups adequately.     

Genetic variation of trypsin and chymotrypsin inhibitors in pigeonpea [Cajanus cajan (L.) Millsp.] and its wild relatives

Variation in the trypsin inhibitors (TIs) and the chymotrypsin inhibitors (CIs) among 69 pigeonpea [Cajanus cajan (L.) Millsp.] strains from a wide geographical distribution and among 17 accessions representing seven wild Cajanus species was studied by electrophoretic banding pattern comparisons and by spectrophotometric activity assays. The TI and CI electrophoretic migration patterns among the pigeonpea strains were highly uniform but varied in the inhibitor band intensities. The migration patterns of the inhibitors in the wild Cajanus species were highly species specific. The mean TI activity of pigeonpea strains (2279 units) was significantly higher than that of the wild Cajanus species (1407 units). However, the mean CI activity in the pigeonpea strains (62 units) was much lower than that in the wild species (162 units). Kenya 2 and ICP 9151 were the lowest and the highest, respectively, in both the TI and CI activities among all the pigeonpea strains used in this study. A highly-significant positive correlation was observed between the TI and CI activities. The Bowman-Birk type inhibitors with both TI and CI activities were identified in all the pigeonpea strains and also in the accessions of all the wild species except C. volubilis (Blanco) Blanco. The C. volubilis accession ICPW 169 was found to be null for both CI bands and CI activity. Environment, strain, and environment x strain interaction showed highly-significant effects on both the TI and CI activities. Growing the pigeonpea strains at a different environment from their area of adaptation increased TI and CI activities and also altered the maturity period.     

On the origin of Spanish two-rowed barleys

To investigate the phylogenetic origin of Spanish two-rowed barleys, we studied 44 accessions of old land-races both morphologically and biochemically to ascertain their similarity with 51 entries of old cultivars and land-races of widespread origin across Europe. They were also compared with 20 accessions of Hordeum spontaneum from the Mediterranean basin and other regions of its distribution range, 14 accessions of Moroccan cultivated six-rowed barley land-races, and different six-rowed Spanish and two-and six-rowed European cultivars. CM-(trypsin inhibitors and subunits of the barley tetrameric -amylase inhibitor) proteins and hordeins, all of which are endosperm proteins, were used as biochemical markers. The appearance of separate clusters of the Spanish barleys in the numerical classifications for both protein systems as a result of the existence of characteristic gene combinations that do not exist in entries from other origins permitted us to postulate the existence of local ancestors for most of the Spanish two-rowed barleys studied, and, therefore, a possible in situ domestication.