The mean C-band number varied from 11.0 to 20.6 in the 0B class, 10.8-18.6 in the 1B class and 10.5-18.6 in the 2B class, showing a negative trend between the B chromosome and C-band number.
Generally only one form of B chromosome is found, although variants can come in fairly frequently resulting in metacentric chromosomes, subtelocentric chromosomes, and minichromosomes (Jones and Houben, 2003).
(2016) suggested that as the maize B chromosome increases in copy numbers, it has a stronger influence on A-genome transcription.
The goals of this study were to (i) estimate B chromosome polymorphisms based on their occurrence, morphology, and frequency in maize landraces from Southwest China, (ii) provide evidence for the evolution of maize landraces from Southwest China, and (iii) infer the geographical origin of landraces in southwest China.
The B chromosome may be cytologically identified as the smallest chromosome in addition to the normal karyotype, and has a size slightly larger than half of the smallest A complement, chromosome 10 (Carlson and Rosemon, 1992).
Three forms of Bs were detected: a metacentric B chromosome (BT), morphologically similar to first chromosomal pair of the standard karyotype (Fig.
It is not know whether Bs in Lolium perenne drive, but several studies have shown that the more densely plants with B chromosome are planted, the better they survive.
Thus, the objective of this study was the assessment and comparison of the number and behaviour of B chromosome during the meiosis and mitosis of an accession of Lolium multiflorum.
Only one accession (ETBAZ 055--from Capao do Leao, Rio Grande do Sul State, Brazil) showed B chromosome. Ten plants from this accession were analysed.
In meiocytes with one B chromosome, they (chromosomes) appear as univalent in diakinesis and metaphases I; when in number of two, they form bivalents.
Studies on B chromosome stability during development.