Authors: B J M Zonneveld
Publish Date: 2014/07/31
Volume: 301, Issue: 3, Pages: 931-953
Abstract
For the first time genome size was determined from a total of 343 wild collected plants from the succulent genera Haworthia and Astroloba Asphodelaceae Alooideae Genome sizes 2C values turned out to be rather close especially within genus Haworthia ss To improve the accuracy of the results in the end 2368 measurements were made The measured nuclear DNA contents provide a further basis for the separation of Haworthia sl into three genera This resulted in 69 recognized species of the new genera Haworthia Haworthiopsis and Tulista The 2C values for the largest genus Haworthia =Haworthia subgenus Haworthia with 45 species varies only from 217 to 247 pg An exception is some accessions of Haworthia nortieri var agnis with up to 272 pg The four varieties of H nortieri are here elevated to species level and placed in a new section Nortierae Zonn The genus Haworthiopsis =Haworthia subgenus Hexangulares are clearly divided in two sections each with 10 species section Coarctatae 252–276 pg and Venosae 289–336 pg The highest value so far for Haworthia sl has been H limifolia which is hexaploid with 998 pg The third genus Tulista =Haworthia subgenus QueryRobustipedunculares with only four species varies from 359 to 372 pg Closely related with Tulista also with respect to genome size is the genus Astroloba including Poelnitzia with nine species and from 304 to 340 pg The results also show that most but not all varieties are correctly attributed to the nominate species A few varieties have been reinstated as species of which two have been renamed in Haworthiopsis Further details are discussed in the main text The genome sizes were compared with the genome sizes of all species of Gasteria Chortolirion and 83 Aloe species Aloidendron =Aloe section Aloidendron with 245–374 pg comes out as the most basal in the published cladogram for the Alooidae It leads to the interesting suggestion that the amount of nuclear DNA of the two species in section Kumara =Aloe section Kumara namely K plicatilis 176 pg and K haemanthifolia 162 pg and species in Aloiampelos =Aloe section Macrifoliae 216 pg have decreased strongly which is a rare phenomenon
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