• W. B. Turrill

      Articles written in Journal of Genetics

    • Studies inRanunculus - I. Preliminary account of petal colour and sex inRanunculus acris andR. bulbosus

      E. M. Marsden-Jones W. B. Turrill

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    • The history of a tetraploid Saxifrage

      E. M. Marsden-Jones W. B. Turrill

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    • Studies in variation ofAnthyllis vulneraria

      E. M. Marsden-Jones W. B. Turrill

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      1. It is shown thatAnthyllis Vulneraria L. is a very polymorphic species, especially in habit and flower colour. The studies deal almost entirely with wild British material.

      2. A considerable number of true-breeding phenotypes have been collected or have appeared in bred generations. Some of these can be included under published varietal names, but it has been necessary to make an arbitrary choice in fixing a standard for the names var.lutea, var.ochroleuca, and var.coccinea. The work shows that taxonomic varieties within wild species may consist of more than one phenotype.

      3. It is shown that a limited number of parental “varieties” by natural crossing can produce heterogeneous populations which consist of very many different phenotypes, some homozygous, some heterozygous.

      4. The introduction of an alien type (var.Amaranth Purple) at Par Sands resulted in a hybrid swarm consisting mainly of phenotypes totally distinct from those occurring where the var.Amaranth Purple was absent.

      5. The results of field studies so strongly confirmed what would otherwise have been tentative suggestions regarding the origin of hybrid phenotypes, that it seems desirable to urge that field studies should always be made in connection with breeding work whenever possible.

      We desire to express our very sincere thanks to Mr G. Atkinson, artist to the Royal Botanic Gardens, Kew, for the excellent coloured figures he has made from our material.

      The research on which this paper is based has been aided by a Royal Society Government Grant.

    • Further breeding experiments withSaxifraga

      E. M. Marsden-Jones W. B. Turrill

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      1. Forty-eight hybrid families involvingSaxifraga granulata andS. rosacea have been made under fully controlled conditions and the results of their analysis are given in this paper.

      2. Segregation was found frequently for corolla characters. This is considered to have a genic basis.

      3. One series of five families showed marked segregations in parental characters. In addition there occurred various plants morphologically peculiar.

      4. In twenty-nine families (with a total of 4068 plants) no segregation into parental characters occurred although all these plants had chromosome complements from bothS. granulata andS. rosacea in their nuclei and were ofF2,F3, or back-cross origin.

      5. In addition to plants not separable fromS. potternensis two new clearly distinguishable but non-segregating types appeared. One was a type with large coarse leaves (with two dosages ofS. granulata) and the other (with two dosages ofS. rosacea) was intermediate in habit and other characters betweenS. potternensis andS. rosacea. The latter was carried through three generations.

      6. In all non-segregating families, except those with two dosages ofS. rosacea, the vegetative characters ofS. granulata dominated completely or largely over those ofS. rosacea.

    • Studies inRanunculus - III. Further experiments concerning sex inRanunculus acris

      E. M. Marsden-Jones W. B. Turrill

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      1. Six “sex” types are recognised inRanunculus acris, normal hermaphrodite, female, male, and neuter, and two intermediate conditions between hermaphrodite and female, termed, for convenience of scoring, minus normal and abnormal.

      2. Variations are not due to differences in chromosome numbers.

      3. Apomixis occurs in a low percentage of ovules, successfully in less than 1 per cent. under the most favourable experimental conditions tested.

      4. The “male” condition is completely recessive to the hermaphrodite and segregates in a ratio probably representing 3:1.

      5. Constant or almost constant female, and constant hermaphrodite plants occur in the wild and as segregates from crosses; male and neuter plants are always constant; many other plants fluctuate between the hermaphrodite and female condition.

      6. A possible genetical scheme is suggested, comparable to that accepted inRubus idaeus, with the hermaphrodite (and types intermediate between this and the female)FM, the femaleF, the maleM, and the neuterfm.

    • Genetical studies inCentaurea scabiosa L. andCentaurea collina L

      E. M. Marsden-Jones W. B. Turrill

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    • Further interspecificSaxifraga hybrids

      E. M. Marsden-Jones W. B. Turrill

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    • A quantitative study of petal size and shape inSaxifraga granulata L.

      E. M. Marsden-Jones W. B. Turrill

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    • Studies onRanunculus ficaria

      E. M. Marsden-Jones W. B. Turrill

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      An account is given of a wide range of plants ofRanunculus ficaria collected from a number of English counties. Various stock plants from among these were selfed and crossed together under full control. Analysis of stock plants and families has been for: presence or absence of tubers in the axils of the cauline leaves, leaf shape, leaf margin, mottling of leaf surface, anthocyanin blotch on leaf surface, petal colour, anthocyanin on back of petals, and sex. Many of the plants have been examined cytologically. The characters listed have been shown to have genetic bases, and for some it has been possible to suggest genetic details.

    • Studies inRanunculus - IV. Additional experiments withRanunculus bulbosus andR. Acris

      E. M. Marsden-Jones W. B. Turrill

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      This paper is a continuation of two previous papers on the genetics ofRanunculus bulbosus andR. acris. Characters studied are flower colour and sex in both species, poor development of petals in the former and leaf blotch in the latter species. Evidence is given that these have all a genetic basis, but the ratios are often disturbed by the occurrence of apomixis and, particularly inR. acris, semi-lethality and perhaps of lethality with certain gene combinations.

    • Additional breeding experiments withSaxifraga - With plates 6–10

      E. M. Marsden-Jones W. B. Turrill

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      Comparative descriptions are given of British material ofSaxifraga rosacea, S, caespitosa, andS. hypnoides.

      Families have been raised from selfings and from crossings of our stock plants of these taxa, and from reciprocal crosses ofS. hypnoides andS. granulata.

      In the discussion it is shown that genetical sterility barriers are not important in keeping the taxa distinct and their absence or incompleteness explains the occurrence of ‘intermediates’ in certain wild populations and in some plants in cultivation.

      The doubtful taxonomic value of the differences betweenS. caespitosa andS. rosacea is considered and the need for further comparative researches, especially on Welsh and Scottish populations, is suggested.

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