The influence of temperature on chromosome pairing in diploid and triploid hybrids between Hordeurn- vulgare L. and H. bulbosum L

Pickering, R. 1990. The influence of temperature on chromosome pairing in diploid and triploid hybrids between Hordeum rdgare L. and H. bulbosum L. —Hereditas 113: 221–226. Lund, Sweden. ISSN 0018–0661. Received September 14, 1990. Accepted September 21, 1990 Differences in chromosome pairing at metaphase I were found in a diploid hybrid between Hordeum vulgare L. (2n%2x = 14) and H. bulbosum L. (2n%2x = 14) grown in contrasting environments, and therefore a larger scale investigation was initiated to assess the influence of temperature on chromosome pairing. This was carried out at 15°C and 21°C using diploid (VB: diploid H. vulgare x diploid H. bulbosum) and triploid hybrids (VBB: diploid H. vulgare x tetraploid H. bulbosum). In most of the hybrids analysed, allosyndetic pairing was significantly higher at 21°C compared with 15°C. but the stability of the hybrids was generally unaffected by temperature. The implications of these findings with regard to a wide hybridisation programme are discussed briefly.