Chromosome Numbers of Poinsettia

Chromosome Numbers for North American Euphorbiaceae

“…Aside from the 2n = 14 reported from a plant of E. dentata from Virginia (Perry, 1943), all other taxa in this subgenus are n = 14, 28 which presumably are polyploids suggesting a basic number of x = 7. This same conclusion was reached by Ewart and Walker (1960), who observed multivalent association in cultivars of Euphorbia pulcherrima having 2n = 28. That the subgen.…”

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“…El nivel de ploidia de los progenitores es un factor determinante en la producción de semillas; Bernuetz (2001) reporta que E. pulcherrima tiene información genética 2n = 28 o 56; el número de cromosomas somáticos de los cultivares es 28 o 56, aquellos con 2n = 28 son diploides, los que poseen 2n = 42 cromosomas se denominan triploides, pero de acuerdo con Ewart & Walker (1960) podrían ser hexaploides. De acuerdo con Milbocker & Sink (1969), la hibridación entre cultivares diploides genera una producción abundante de semillas; sin embargo, al cruzar diploides femeninos con tetraploides, se obtiene menos de 1% de semillas viables, el desarrollo de endospermo en Imported varieties present problems as the reduction or the excess of vegetative growth, early beginning of flowering (in September) or lack of pigmentation in the bracts; the previous mentioned is a consequence of the climatic differences among production zones and the generation areas of the varieties.…”

“…The ploidy level of progenitors is a determining factor in seed production; Bernuetz (2001) reported that E. pulcherrima has 2n = 28 or 56 genetic information; the number of somatic chromosomes of the cultivars is 28 or 56, those with 2n = 28 are diploids, those that own 2n = 42 chromosomes are called triploids, but according to Ewart & Walker (1960) they could be hexaploids. According to Milbocker & Sink (1969) w2, presenta un régimen de lluvias de 1200 mm anuales en promedio y una temperatura media anual de 21.5 °C (García, 1981 (García, 1981).…”