Microsporogenesis associated with seed yield in Urochloa sexual polyploid hybrids

Abstract

High seed yield is a fundamental characteristic of apomictic and sexual hybrids of the genus Urochloa P. Beauv. (syn. Brachiaria (Trin.) Griseb.). It has been suggested that there is an association between polyploidy, the presence of meiotic irregularities, and low seed formation in this genus. The present study aimed to correlate these characteristics in Urochloa polyploid sexual interspecific hybrids in relation to the production of pure seeds. Segregational and non-segregational abnormalities were shown to led to cause the formation of tetrads with micronuclei, microcytes, polyads, and anomalous end products. The correlation between the percentage of meiotic abnormalities and the total production of pure seeds was negative and significant. To our knowledge, this is the first research with sexual polyploid hybrids from Urochloa and is relevant to identify hybrids with less frequent meiotic abnormalities and higher seed yield, with promising female parents for the breeding program.

Keywords:
Brachiaria; segregational irregularities; micronucleus; polyad; seed set