2015 Volume 80 Issue 3 Pages 303-309
Numerous naturally occurring mutations are heterozygous, and thus, a contributing source of variation. Their crucial fate rests on the gametic fertility and viability. Translocations have been reported in many plant species; however, no previous report is available in this regard in Trachyspermum ammi (L.) Sprague (ajwain). During meiotic analysis, a heterozygote for reciprocal translocation has been isolated from the population through EMS treated set in ajwain var. AA-1. The results of the cytological studies showed the predominance of ring quadrivalents along with seven bivalents. Some extent of univalents and bivalents with multiple chromosomal associations along with rings and chains were also observed at metaphase I. Heterozygous plant showed reduced pollen fertility up to 36.23% due to the predominance of adjacent orientation over alternate. At anaphase I, some pollen mother cells (PMCs) showed normal 9 : 9 separation but simultaneously, abnormal 8 : 10 chromosomal separation was also observed. This study deals with the cytological behavior of heterozygote and its occurrence and consequences in the present crop.
