Male Sterility in Pea II. Male sex specific dys-synapsis.

Towards male sterility in Cryptomeria japonica using the male strobilus-specific genes of C. japonica

Background Cryptomeria japonica D. Don (sugi) is one of the most important Japanese conifer species. Rapid improvement of the wood trait (e.g., growth speed and wood quality) using a conventional breeding approach is not possible, because breeding of coniferous tree requires a very long time. Genetic modification might be a powerful tool to shorten the time needed to breed trees compared with t...

Mechanisms of Genic Male Sterility

For normal sexual reproductive development, coordination must occur between both male and female organ ontogeny. An abnormality at any point in this process may lead to sterility. Classification of sterility can be divided into heritable and nonheritable sterility. Numerous schemes for mechanisms controlled by nuclear genes (genic male sterility) have been devised to identify the timing and loc...

Cytoplasmic male sterility in Brassicaceae crops

Brassicaceae crops display strong hybrid vigor, and have long been subject to F1 hybrid breeding. Because the most reliable system of F1 seed production is based on cytoplasmic male sterility (CMS), various types of CMS have been developed and adopted in practice to breed Brassicaceae oil seed and vegetable crops. CMS is a maternally inherited trait encoded in the mitochondrial genome, and the ...

Cytogenetic Investigations in Couples with Male Sterility

Sterility in mutant ( tLxjtLy ) male mice

The results from a comparative ultrastructural study of spermiogenesis in 6-, 10-, 14and 17-month-old sterile t/t, and fertile T/t«, T/t and BALB/c, mice are reported. The studies show that all of the males contained the same types of defective spermatids and that defects were not limited to specific spermatid stages. Younger males had fewer abnormal spermatids than older males of the same geno...