Past, Present, and Future X-Ray and Gamma-Ray Missions

X- and -ray astronomy began in the early sixties of the last century with balloons flights, sounding rocket experiment and satellites. Long before space satellite detected X- and -rays emitted by cosmic sources, scientists had known that the Universe should be producing these photons. In this chapter we provided an overview of past and present missions that has made the X- and -ray astronomy an integral part of astronomical research, and prospects of future developments

Controlled self and cross-pollination of Trifolium

The difficulties encountered in making reliable controlled self- and cross-pollinations are limiting factors in breeding and genetic studies with many species. Several investigators have made successful self- and cross-pollinations with white clover, but only Williams has published his technics in detail. In the course of breeding and genetic studies with white clover since 1937 there have been developed several pollination technics which are relatively simple to execute and which yeild reasonably precise results

Natural crossing of white clover by bees

ALTHOUGH an understanding of the mode of pollination is generally considered a prerequisite to the intelligent planning and pursuing of a profitable breeding program, detailed information on this subject has not been available previously for white clover (Trifolium repens L.). It has long been recognized, however, that honey bees are the most common pollinating insects for white clover and that seed set in the open is usually good if pollination has been adequately effected under proper environmental conditions. Since it was also known that most clones of white clover are self-sterile (9, 7, 2) it has generally been assumed that the species should be classed as naturally cross-pollinated under most circumstances. Though this assumption may hold for the majority of clones, the present study shows that it certainly does not apply to those bearing the self-compatibility factor (4)