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Apomixis in American Polyploid Blackberries

John Einset
American Journal of Botany
Vol. 38, No. 10 (Dec., 1951), pp. 768-772
Stable URL: http://www.jstor.org/stable/2438199
Page Count: 5
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Apomixis in American Polyploid Blackberries
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Abstract

Somatic chromosome counts were made of 1,620 seedlings from selfed, crossed and open-pollinated polyploid American blackberries. Twenty-four different seed parents representing 5 different sections of the Eubati or true blackberries were included. The parental plants had somatic chromosome numbers of 21, 28, 35, 36, 49, and 63. All produced a high proportion (80 to 100 per cent) of apomictic seedlings with chromosome numbers like those of the seed parents. This was true after selfing, crosslng with plants having different chromosome numbers, or on open pollination. Apparently these seedlings were produced pseudogamously from unreduced eggs. Numerous cases of reduced parthenogenesis also were observed, notably in the tetraploid, 28-chromosome species where 43 individuals with 14 somatic chromosomes were found in a population of 681 seedlings., Hybrid seedlings resuked infrequently after fertilization of reduced or unreduced eggs.

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