Abstract

Selection for manual tripping (MT) was effective in improving self-fertility (SF) in all populations and generations over original parents. Selection for MT was accompanied by improving fertility of open pollinated (OP) populations. Self-seed set (ST) was very poor. Some individual selections set seeds up to 88% in MT materials. The enigma of fertility, sterility and absence of inbreeding depressions in berseem was discussed. This was explained as inbreeding tolerance, due to selection for good vigor accompanying inbreeding. The results indicated that selection for high MT seed set could be accompanied by selection for good forage yield. An approach was suggested to develop new composite varieties characterized by high seed fertility and high forage yield. Improved selections for seed production was mainly due to profuse flowering and more flowers/ inflorescence, whereas improved forage yield was mainly due to more tillers / plant and to less degree of plant height. An approach was outlined to produce new composites with high seed setting and good forage. T. alexandrinum is self-compatible, but needs tripping to stimulate self seeds. This is mainly due to the relative position of male and female organs and the presence of bubbles on stigma. Molecular characterization revealed polymorphic differences between I_o and selected inbred.

Key words: Trifolinm alexandrinum, fertility, yield, tripping, compatibility, inbreeding.