Cytology of F1hybrids and chromosome number of F2and BC1progeny of the crossBromus ripariusxB. inermis

✍ Scribed by K. C. Armstrong

• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 598 KB
• Volume: 79
• Category: Article
• ISSN: 0040-5752
• DOI: 10.1007/bf00223800

✦ Synopsis

Hybrids between B. inermis Leyss (2n=8x=56) and B. riparius Rehm. (2n=10x=70) were easily made. The F1 hybrids had a fertility of 20%-50% under open pollination and backcrossing to B. inermis. Chromosome pairing in B. riparius was predominantly as bivalents (29.04-33.85 per cell for plant means). Bivalents also predominated in the F1 hybrid (2n=9x=63) and there was a high level of pairing with no reduction in chiasma frequency. It was impossible to estimate the frequency of auto-versus allosyndetic pairing. Chromosome pairing in a hybrid between B. arvensis (2n=2x=14) and B. riparius confirmed that the B. riparius complement is capable of complete autosyndetic pairing. Chromosome numbers in the F2 progeny ranged from 2n=56 to 72 but they were skewed towards 2n=63 to 70. Backcrosses ranged from 2n=56 to 63, as expected, with the distribution skewed towards 2n=56. Selection towards the 2n=56 level would be difficult in the F2. Empirical observation suggested that cytoplasm had a major influence on morphology in the backcrosses. Additional studies are required to determine the best breeding scheme to introgress germ plasm between B. inermis and B. riparius.