Experiments in plant hybridisation / Mendel's original paper in English translation, with commentary and assessment by Sir Ronald A. Fisher, together with a reprint of W. Bateson's biographical notice of Mendel ; edited by J.H. Bennett.

  • Mendel, Gregor, 1822-1884. Versuche über Pflanzenhybriden. English
Date:
[1965]
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Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Experiments in plant hybridisation / Mendel's original paper in English translation, with commentary and assessment by Sir Ronald A. Fisher, together with a reprint of W. Bateson's biographical notice of Mendel ; edited by J.H. Bennett. Source: Wellcome Collection.

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    l8 EXPERIMENTS IN PLANT HYBRIDISATION These two experiments are important for the determination of the average ratios, because with a smaller number of experi¬ mental plants they show that very considerable fluctuations may occur. In counting the seeds, also, especially in Expt. 2, some care is requisite, since in some of the seeds of many plants the green colour of the albumen is less developed, and at first may be easily overlooked. The cause of this partial disappearance of the green colouring has no connection with the hybrid- character of the plants, as it likewise occurs in the parental variety. This peculiarity [bleaching] is also confined to the individual and is not inherited by the offspring. In luxuriant plants this appearance was frequently noted. Seeds which are damaged by insects during their development often vary in colour and form, but with a little practice in sorting, errors are easily avoided. It is almost superfluous to mention that the pods must remain on the plants until they are thoroughly ripened and have become dried, since it is only then that the shape and colour of the seed are fully developed. Expt. 3. Colour of the seed-coats.—^Among 929 plants, 705 bore violet-red flowers and grey-brown seed-coats; 224 had white flowers and white seed-coats, giving the proportion 3-15 to I. Expt. 4. Form of pods.—Of 1181 plants 882 had them simply inflated, and in 299 they were constricted. Resulting ratio, 2*95 to I. Expt. 5. Colour of the unripe pods.—The number of trial [experimental] plants was 580, of which 428 had green pods and 152 yellow ones. Consequently these stand in the ratio 2-82 to I. Expt. 6. Position of flowers.—Among 858 cases 651 had inflorescences axial and 207 terminal. Ratio, 3*14 to i. Expt. 7. Length of stem.—Out of 1064 plants, in 787 cases the stem was long, and in 277 short. Hence a mutual ratio of 2-84 to I. In this experiment the dwarfed plants were carefully lifted and transferred to a special bed. This precaution was necessary, as otherwise they would have perished through being overgrown by their tall relatives. Even in their quite