Wheat family biosystematics. Volume 2

Author: Yan Ji, Yongliang
Publisher:
Publish Date: 2004-05-01
Features: In the genera of Hordeum and Taeniatherum included in this book, there is a strong reflection of specific genetic effects in heterosis and sexuality, which must be taken into account when performing systematic analysis. For example, in Chinese wheat landraces, there are some containing four pairs of high- genes, namely kr1, kr2, kr3, and kr4. If such materials are crossed with rye, their seed-setting rate can reach over 95%, suggesting no reproductive isolation. However, the new chromosomes fail to pair during meiosis in the offspring, and the hybrids remain sterile. In the genus Taeniatherum, Taeniatherum asperum has evolved strict self-pollination under extreme drought conditions through natural selection, resulting in a special genetic system. This leads to potential incompatibility between different populations, causing high intraspecific reproductive isolation. Yet, their morphological characteristics and chromosome types are identical. Although these are extremely rare and special phenomena, they are indeed objective realities that we must pay attention to. Such special phenomena will be encountered in this volume.