Meiotic and breeding behaviour of primary trisomics in pearl millet

The meiotic behaviour of the primary trisomies of Pennisetum typhoides indicated that the transmission frequency should be high. At diakinesis 52-8% cells showed 1_III+6_II, and at anaphase-I, 8–7 chromosome distribution was observed in 93⋅6% cells. In the progenies of the selfed trisomies and trisomic-diploid crosses, only 3⋅4 and 7⋅7 per cent plants respectively were trisomies, while 1 ⋅ 3 per cent plants were trisomies in the crosses where trisomies were used as the pollen parent. The low trisomic frequency is mainly attributed to the subnormal development of trisomic seeds, their poor and delayed germination and reduced vigour of the trisomic seedlings. Selecting small seeds from the different trisomies and growing them separately improved the recovery of the trisomies, 2⋅1% plants raised from the large seed and 26⋅8% from the small seed were trisomies.