CHIASMA FREQUENCIES IN PRIMARY TRISOMICS OF PEARL MILLET

Abstract

Seven primary trisomics were obtained in the progeny of an autotriploid Pennisetum typhoides (Burm.) S. &H. The trisomics could be distinguished from the diploids and from one another morphologically and were designated Dwarf, Bush, Slender, Semidwarf, Purple, Robust and Pseudonormal. In Purple and Pseudonormal the mean chiasma frequencies were significantly higher than in the diploid sibs but in Dwarf the mean chiasma frequency was significantly lower. In the other trisomics the chiasma frequencies did not differ from the diploid sibs. The trivalent frequencies and configurations varied in the different trisomics and no correlation was noticed between the length of the chromosome and trivalent frequency but one was observed between trivalent frequency and chiasma frequency.