Chromosome Numbers and DNA Content in Some Taxa of Leucaena (Fabaceae Mimosoideae)

Abstract

Somatic chromosome numbers and 2C DNA values of seven taxa of Leucaena are reported. Leucaena diversifolia subsp. diversifolia, L. d. subsp. stenocarpa, L. lancoelata subsp. lancoelata and L. 1. subsp. sousae were diploid. Leucaena confertiflora subsp. adenotheloidea and L. esculenta subspa paniculata were tetraploid. Leucaena esculenta subsp. esculenta, showed diploid and tetraploid froms. Diploid taxa showed intra-individual variation with 2n=52, 54 and 56, the most frequent being 2n=56. Tetraploid taxa showed 2n=104, 108, 110 and 112, the most frequent being 2n=112. In five diploid taxa of Leucaena studied 2C DNA values showed significant) variation only between L. diversifolia subsp. diversifolia (1,81pg) and L. esculenta subsp. esculenta (1.35pg). Genome size did not differ among subspecies pairs (L. d. subsp. diversifolia vs L. d. subsp. stenocarpa and L. lanceolata subsp. lanceolata vs L. 1. subsp. sousae). In three tetraploid taxa analyzed, DNA content varied between 2.66 pg (L. esculenta subsp. paniculata) and 3.31 pg (L. confertiflora subsp. adenotheloidea). DNA content of tetraploids was approximately twice that of diploids, suggesting that the polyploid taxa studied have a relatively recent origin. No relation was found between incipient domestication of L. confertiflora subsp. adenotheloidea and ploidy level. © 1995, Japan Mendel Society, International Society of Cytology. All rights reserved.