Meiosis in Nine Species of Jute (Corchorus)

Meiotic analysis performed in nine species of jute (cultivated species - C. olitorius L., C. capsularis L.; wild species - C. fascicularis Lamk., C. aestuans L., C. pseudoolitorius I. and Z., C. pseudocapsularis L., C. tridens L., C. trilocularis L. and C. urticaefolius W. and A. - Family: Tiliaceae) revealed that C. olitorius (mean/cell: 7II), C. capsularis (mean/cell: 6.98 II + 0.03 I), C. tridens (mean/cell: 6.98 II + 0.03 I), C. trilocularis (mean/cell: 7 II) and C. urticaefolius (mean/cell: 7 II) formed 2n=14 chromosomes at metaphase I always with balanced (7/7) segregation at anaphase I; while, C. fascicularis Lamk. (24.42%-MI; 1.79%-AI), C. aestuans L. (33.33%-MI; 28.57%-AI), C. pseudoolitorius I. and Z. (24.69%-MI; 15.73%-AI) and C. pseudocapsularis L. (2.56%-MI; 0.00%-AI) exhibited numerical variations in chromosome number (n=1,2,3,4,5,6,9,10 and 14) in addition to normal (n=7). Average chromosome association per cell at MI was 0.002 VI + 0.006 IV + 6.98 II + 0.31I in C. fascicularis, 6.55 II + 0.60 I in C. aestuans, 6.60 II in C. pseudoolitorius and 7.08 II + 0.21 I in C. pseudocapsularis. Aneuploidy noted in jute species is attributed to cytomixis. Chromosome in the species were mostly bivalents (6.55 - 7.08 mean/cell; random in distribution - p> 0.05) and rarely univalents (0.00 - 0.60 mean/cell; nonrandomly distributed - pC. fascicularis. Bivalents in the species were of ring (1.44 ± 0.13 to 4.68 ± 0.14/cell) and rod (2.32 ± 0.14 to 5.44 ± 0.14/cell) configurations. Excepting C. capsularis, the species formed more of rod bivalents than ring. Ring and rod bivalents were nonrandom (p< 0.001); while chiasmata per cell (8.40 - 11.68) and per bivalent (1.20 - 1.67) was random (p> 0.50) in distribution among species as evident from chi - square test of heterogeneneity. Pollen fertility in the species varied from 59.82% - 96.91%.