AN INVESTIGATION OF CHROMOSOME-NUMBERS IN THE GENUS BRACHIARIA (POACEAE, PANICEAE) IN RELATION TO MORPHOLOGY AND TAXONOMY
AN INVESTIGATION OF CHROMOSOME-NUMBERS IN THE GENUS BRACHIARIA (POACEAE, PANICEAE) IN RELATION TO MORPHOLOGY AND TAXONOMY
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DOI：
10.1139/b87-313
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发表时间：
1987-11-01
期刊：
影响因子：
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通讯作者：
CHINNAPPA, CC
中科院分区：
文献类型：
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作者：
BASAPPA, GP;MUNIYAMMA, M;CHINNAPPA, CC
对印度次大陆臂形属 32 个类群 260 个种群的染色体数目测定和形态学研究表明，所有有性繁殖的类群都没有染色体种族。六个无性系群，即 B. brizantha var. brizantha (n = 27), B. brizantha var. ciliata (n = 18)、B. decumbens (n = 18)、B.hybrida (n = 27)、B. mutica (n = 18) 和 B. setigera var. albistyla (n = 14)，基于 x = 7、8 和 9，始终表现出染色体数量的一致性。 setigera 是一种遗传不稳定的无融合生殖体，是唯一倾向于具有异倍体系列的分类单元（n = 16、17、18、21 和 32）。 B. setigera var. 的种群数量n = 17 的 setigera 是基于 x = 17 的次级碱基数。该属中有 6 个二倍体、20 个四倍体、5 个六倍体和 3 个八倍体。非整倍体和三倍体在该属中通常不存在，但不能排除它们在 B. setigera 复合体中可能存在的可能性。在一些物种中，某些先前报告的染色体数目与本研究存在偏差，被发现是错误识别的结果或分类学复杂情况的结果，例如在 B. brizantha、B. distachya 复合体和 B. ramosa 复合体中发现的结果。
Determinations of chromosome number and morphological studies of 260 populations, belonging to 32 taxa, of the genus Brachiaria from the Indian subcontinent reveal that all sexually reproducing taxa have no chromosome races. Six agamic taxa, viz., B. brizantha var. brizantha (n = 27), B. brizantha var. ciliata (n = 18), B. decumbens (n = 18), B. hybrida (n = 27), B. mutica (n = 18), and B. setigera var. albistyla (n = 14), have consistently shown uniformity in chromosome numbers, based on x = 7, 8, and 9. Brachiaria setigera var. setigera, a genetically unstable apomict, is the only taxon that tends to have a heteroploid series (n = 16, 17, 18, 21, and 32). The population of B. setigera var. setigera with n = 17 is based on a secondary base number of x = 17. There are 6 diploids, 20 tetraploids, 5 hexaploids, and 3 octoploids in the genus. Aneuploidy and triploidy are characteristically absent in the genus, although their plausible existence in the B. setigera complex cannot be ruled out. In several species certain previously reported chromosome numbers that deviate from the present study are found to be the result of erroneous identifications or the result of taxonomically complex situations such as those found in B. brizantha, the B. distachya complex, and the B. ramosa complex.