The Genetics of Squareheadedness and of Density in Wheat, and the Relation of These to Other Characters

The Genetics of Squareheadedness and of Density in Wheat, and the Relation of These to Other Characters

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 edition. Excerpt: ... dominant. Four of these crosses, of which two were with squareheads and the other two with vulgare, were carried through the F2 generation in order to test whether the assumption of the presence of one factor was correct. The results obtained are condensed and given in table 18. Of the 125 F2 plants tested, 30 were homozygous dense, 67 produced both dense and lax forms, and 28 were homozygous lax. These figures, compared with the calculated propot-tions--31.2 1 3. 3, 62.5 1 3.9, and 31.2 r 3.3, respectively--sh0w a very close agreement with the 1:2: I ratio. The proportion of plants obtained in each cross taken separately agrees also with the theoretical expectancy, the largest departure being but 25 per cent more than its probable error. l I TABLE 18. PROPORTIONS or Homozvcous D1-: NsE, HETEROZYGOUS DENSE, AND Homozvcous LAX PLANTS or THE F12 GENERATION or SER1Es TESTED IN THE F3 GENERATION The behavior of each individual F2 plant of the four crosses under consideration is shown respectively in tables 19, 20, 21, and 22, Of the TABLE 19. BEHAVIOR or F2 PLANTS IN F3. 52R1125 131_72a, MEALY (VULGARE) x 669 heterozygous plants obtained in series I 3172a (table 19), 517 were dense and 152 were lax, the deviation from the calculated ratio being about twice its probable error. In series 13173a (Itable 20), the ratio between the probable error and the deviation from expectation is I: 5.22, which is rather high. In series 1317421 (table 21) this ratio is I: 5.02, and in series 13214a (table 22) it is only 1: 0.46. All these results, in spite of the differences between observed and calculated ratios which TABLE 20. BEHAVIOR or F2 Pumrs IN F3. SERIES 13174a, New Souuas (CAPITATUM) x DALE GLORIA only one factor is involved in the production of density...show more

Product details

  • Paperback | 24 pages
  • 189 x 246 x 1mm | 64g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236637364
  • 9781236637369