TY  - BOOK
AU  - Palomino,G.
AU  - Martínez,J.
AU  - Méndez,I.
AU  - Muñoz-Urías,A
AU  - Cepeda-Cornejo,V
AU  - Pimienta-Barrios,E.
TI  - Nuclear genome size, ploidy level and endopolyploidy pattern in six species of Opuntia (Cactaceae)
KW  - ENDOPOLYPLOIDY
KW  - GENOME SIZE
KW  - OPUNTIA
KW  - PLOIDY LEVEL
N2  - This study describes the haploid chromosome number (n), recombination index (RI), ploidy level and DNA content by DNA flow cytometry of six Opuntia (prickly pear)species from Mexico. Opuntia heliabravoana was diploid (2n =2x = 22, x = 11)with RI = 26; O. jonocostle, O. matudae and O. oligacantha were hexaploid (2n = 6x = 66)with RI = 74, 71, and 83, respectively; and O. hyptiacantha and O. tomentosa were octoploid (2n = 8x = 88)with RI = 99 and 103, respectively. The 2C DNA content was 3.81 pg in Opuntia heliabravoana. For hexaploid species 2C DNA content was: O. jonocostle = 5.84, O. matudae = 5.91 and O. oligacantha = 5.98 pg. The octoploid species O. hyptiacantha and O. tomentosa showed 2C DNA = 7.39 and 7.43 pg, respectively. The 1Cx = 1.91 pg for diploid O. heliabravoana was 52 percent higher than the hexaploid species (mean 1Cx = 0.99 pg)and 48 percent higher than the octoploid species (mean 1Cx = 0.93 pg). These results suggest a loss of some DNA sequences after polyploidization in these Opuntia species. All accessions showed endopolyploidy, defined by the presence of nuclear populations of 2, 4 and 8C in cells of the stem parenchyma. The presence of endopolyploidy and polyploidy in prickly pear provide these plants with adaptive advantages in arid and semiarid environments. These results provide useful guidelines to set conservation strategies and breeding approaches for Opuntia species. © 2016 Dipartimento di Biologia Evoluzionistica, Università di Firenze
UR  - https://drive.google.com/file/d/1rO8W4kKmEopAG1fU3pJIcT5F6X5_ErmI/view?usp=drivesdk
ER  -