Genetic relationships among the annual species of Cicer L.

Summary Genetic relationships between 7 annual species of the genus Cicer, including the cultivated chickpea, have been studied. These species were assigned to 3 crossability groups. In each group interspecific hybrids could be obtained but their fertility differed considerably in the various cross combinations. Crosses between members of different groups yielded no viable seeds. The possibility of gene transfer from the wild species to the cultivated chickpea C. arietinum was also assessed. Only two species could be considered for this purpose, C. reticulatum, which is the wild progenitor of the cultivated species, and C. echinospermum, which is in the secondary gene pool of C. arietinum. A unique postzygotic reproductive barrier mechanism was found between the members of Group II, C. judaicum, C. pinnatifidum and C. bijugum. It is based on a disharmony in the growth rate of the stigma and the anthers at the time of anthesis of the F₁ interspecific hybrid so that selfpollination is avoided. It is proposed that this kind of mechanism has been involved only when an effective spatial isolation between the three species had been obtained.     

Clinical applications of cytometry: 6th annual meeting.

The Sixth Annual Clinical Applications of Cytometry Meeting was held September 11-14, 1991, in Charleston, SC. Attendance reached a record 470. The meeting provides a forum for interactions among investigators who utilize cytometry as a tool in their clinical immunology, cell biology, hematology, and cancer investigations. Clinical laboratory directors and their technical staff find the meeting of practical value because of the presentation of new applications that they can take home to their own laboratories. The emphasis of the meeting is on advances in the application of cytometry to clinical problems. Often, advances result from new dyes or reagents or improved instrumentation. Sometimes they result from advances in biology that make the studies possible. Occasionally a new way of looking at the same data provides a useful answer. In every case, the effort is to provide a reliable, straightforward way to quantitate biologic information in order to provide improved diagnosis or treatment of human disease.