In all the flowers of Vigna species studied under Ibadan conditions, anthesis took place just before, or simultaneously with, the opening of papilionaceous corolla. Hence, flower buds destined to open the following morning are ready for emasculation. These buds have reached their maximum unopened size and have started to pale slightly from the deep rich green of earlier development.
Emasculation and pollination can be carried out at almost any time of the day. Under Ibadan conditions, emasculation and pollination in the late afternoon were highly successful. Apparently, cool nights provide better conditions for fertilization than the hotter daytimes.
Grasp the bud selected for emasculation firmly but gently in such a way as to avoid any stress at the fragile attachment of the bud and raceme. Cut about two-thirds the width of the unopened bud in the center of the bud starting from its straight edge. (The opposite, curved or hooked edge encloses the style and stamens, which must not be injured).
Use small finely pointed forceps, dissecting scissors, scalpels
or even long thumbnails to make the cut
Dip the scissors or forceps in alcohol (75-95%) between crosses, and do not touch the receptive green tipped stigmatic surface before pollinating. This emasculation procedure requires no longer than 15-25 seconds per flower.
|Objectives, Study materials, Practicals|
|1||Principles of cowpea crossing|
|7||Suggestions for trainers|