Genetic Interrelations of Two Andromonoecious Types of Maize, Dwarf and Anther Ear

Attention was called by Montgomery (1906)to the occasional appearance of perfect flowers in the staminate inflorescence of maize and similar cases were reported by Kempton (1913). Montgomery (1911) described with illustrations a true-breeding type of semi-dwarf dent maize, the ears of which were perfect-flowered. Perfect-flowered maize was described and illustrated also by Blaringhem (1908, pp. 180-183). East and Hayes (1911, pp. 13, 14) noted and illustrated a perfect-flowered sweet corn. Weatherwax (1916, 1917) showed that typically pistillate flowers of maize exhibit in microscopic sections the rudiments of stamens and that staminate flowers show rudiments of pistils

Control of Flowering in Teosinte: Short-Day Treatment Brings Early Flowers

Attempts to force teosinte into flower in mid-summer, in order to facilitate hybridizing it with maize, have afforded considerable information concerning the flowering time of teosinte under diverse conditions. The possibility that some of this information may be of use to others suggests its publication. The paper is, therefore, to be considered as a help in the technique of teosinte and maize hybridization rather than a contribution ~to the solution of the physiological problems involved

The Inheritance of Sizes and Shapes in Plants

Some years ago Lock reported a cross of a tall race of maize with a shorter race which produced an intermediate height in F1 and exhibited no segregation in F2 when crossed back with one of the parents. Castle\u27s results with rabbits are very similar to those of Lock with maize. Castle summarizes his results in part as follows: A cross between rabbits differing in ear-length produces offspring with ears of intermediate length, varying about the mean of the parental ear-lengths. . . . A study of the offspring of the primary cross-breds shows the blend of the parental characters to be permanent. No reappearance of the grand parental ear-lengths occurs in generation F2, nor are the individuals of that second generation as a rule more variable than those of the first generation of cross-breds.. . It seems probable that skeletal dimensions, and so proportions of skeletal parts, behave in general as blending characters. The linear dimensions of the skeletal parts of an individual approximate closely the mid-parental dimensions

Heritable Characters of Maize II.-Pistillate Flowered Maize Plants

In the freak class at the Annual Corn Show held at Lincoln, Nebraska, in the winter of 1913-14, there was exhibited a corn tassel with a heavy setting of seeds. A few seeds are not infrequently found in the staminate inflorescence of maize, particularly in pod com, and tillers of various corn varieties often end in ears instead of in tassels or have tassels, the central spikes of which are ear like. The freak exhibited at the com show, however, was a large. much branched affair. wholly tassel-like in form except for the fact that it bore a heavy crop of seed like. a well-filled head of broom corn or sorghum. It retained no indication of having had any staminate flowers. It was apparently a wholly pistillate inflorescence, though tassel-like in form

A Genetic View of Sex Expression in the Flowering Plants

It seems a conservative statement to say that studies of the past twenty years among animal forms have tended increasingly to link the phenomena of sex inheritance with the behavior of chromosomes. To this result, cytology and genetics have contributed perhaps almost equally. The number of forms in which one sex is known to have a morphologically different chromosome complex from the other sex are many. That, with respect to the chromosomes, the female of certain forms produces gametes of a single kind, whereas the male produces two kinds, and that in turn an egg fertilized by one kind of sperm gives rise to a female and with the other kind to a male, cytological studies leave no doubt. In other forms it is the female that produces two kinds of gametes and the male one kind. The fact that in some animals sex dimorphism is associated with unequal numbers of chromosomes while in others, though the numbers are the same, the sex chromosomes differ morphologically in the two sexes, makes it seem not unlikely that functional dimorphism may exist even where no morphological differences in the chromosomes are seen

A Genetic Study of Plant Height in Phaseolus vulgaris

When pole and bush beans are crossed, 3:1 segregation results whether the pole bean is very tall or only medium in height and whether the bush bean is very short or relatively tall. To determine the interrelation of these two types of behavior by an analysis of the factors concerned in height of plants in beans and by a study of their mode of inheritance was the object of the investigations reported here

The Frequency of Somatic Mutation in Variegated Pericarp of Maize

Some years ago (Emerson 1922) the writer announced that in F2 of certain crosses of variegated with colorless pericarp in maize the heterozygous individuals changed to self color more frequently than did the homozygous individuals of the same cultures. No “explanation” of this phenomenon was then apparent, but later results, though still far from affording an adequate solution of the problem, have furnished at least a working hypothesis. The original unpublished paper, with minor modifications, is given below, under the heading. “Somatic mutations in heterozygous and in homozygous variegated pericarp.

Discussion and Correspondence Coupling vs. Random Segregation

To the editor of science: The suggestion offered by Morgan, in SCIENCE of September 22, to account for the coupling and repulsion of factors for various characters in inheritance in such forms as Abraxas, Drosophila, fowls, sweet peas, etc., incites this note. Briefly Morgan\u27s hypothesis is (1) that the materials representing factors that couple are near together in a linear series in the chromosomes; (2) that, when pairs of parental chromosomes conjugate, like regions stand opposed ; (3) that homologous chromosomes twist around each other, but that the separation of chromosomes is in a single plane ; (4) that, thereby the original materials will, for short distances be more likely to fall on the same side of the split, while more remote regions will be as likely to fall on one side as on the other; (5) that, in consequence, whether characters are coupled in inheritance or are independently inherited depends upon the linear distance apart of the chromosomal materials that represent factors

The Genetics Congress

Mice and men reported from Edinburgh after the Congress (JOURNAL OF HEREDITY for September 1939) but since then there has been silence, as far as getting into the record any details of the Congress. On account of the disruption to trans-Atlantic travel caused by the declaration of war between England and Germany, September 3, the American delegation to the Congress was considerably delayed in getting back. Only two failed ultimately to return, Dr. and Mrs. F. W. Tinney of the Division of Farm Crops of the University of Wisconsin. They were among about a dozen members of the Congress who took passage on the ill-fated Athenia. Just how they were lost is uncertain, but there is reason to believe they may have been on the lifeboat which was struck by the propeller of one of the rescue ships

Shorter Articles and Reports: The Simultaneous Modification of Distinct Mendelian Factors

In another paper on the inheritance of a recurring somatic variation in variegated ears of maize, it was shown that the amount of red color developed in the pericarp of variegated seeds bears a definite relation to the development of color in the progeny of such seeds. The relation is such that the more color there is in the pericarp of the seeds planted the more likely are they to produce plants with wholly self-red ears and correspondingly the less likely to produce plants with variegated ears. Self-red ears thus produced behave just as if they were hybrids between self-red and variegated races or self-red and white races, the behavior in any given case depending upon whether the parent variegated ears were homnozygous or heterozygous for variegated pericarp and whether they were self-pollinated or crossed with white