Chromosome association and chiasma frequency of cultivated wheat (Triticum aestivum L.) in Bangladesh

Chiasma frequency estimation is usually considered a good indicator for genetic recombinations in a population, especially in polyploid organisms like hexaploid wheat (Triticum aestivum L.). The hexaploid wheat is functional as diploid with 21 bivalents (21 II), indicating the chromosome number 2n=6x=42. The aim of this study is to identify chromosome association and chiasma frequencies of seventeen cultivated wheat varieties in Bangladesh. Chiasma distribution and its frequencies were studied by using pollen mother cells (PMCs). Data were recorded from diakinesis and metaphase-I of meiotic-I cell division. Mean chiasma frequency per cell and per bivalent were varied in studied varieties which ranged from 40.28 to 40.87 and 1.92 to 1.95 in Sonora-64 and Barkat, respectively. The percentages of ring bivalent were extensively more than rod bivalent in all of the studied varieties. From our observation, it can be stated that chiasma distribution and its frequency varied marginally in seventeen commonly cultivated wheat varieties of Bangladesh. From this observation, it can be stated that commonly cultivated wheat varieties of Bangladesh are closely related to their primary genepool and it is possible to improve those varieties crossing with different genepool imported from other countries.