Ph' gene derived from Aegilops speltoides induces homoeologous chromosome pairing in wide crosses of Triticum aestivum

Abstract

The present study was conducted to investigate the effectiveness of the Ph' gene transferred from Aegilops speltoides into bread wheat cultivar Chinese Spring (CS) in inducing homoeologous chromosome pairing in interspecific crosses using the Chinese Spring line, CS(Ph'), carrying the gene. Chinese Spring, as well as CS(Ph'), were crossed as female parents with three accessions of Ae. kotschyi (UUSS), one accession of Secale cereale (RR), two amphiploids of Triticum durum-Ae. caudata (AABBCC), and one amphiploid of Triticum durum-Ae. umbellulata (AABBUU). Meiotic metaphase I chromosome pairing was studied in all the interspecific crosses with CS as well as CS(Ph'). There was significant increase in chiasma frequency in all the crosses with CS(Ph') over those with CS. The extent of induced homoeologous chromosome pairing by Ph' in crosses of CS(Ph') with S. cereale was higher than with those of Ae. Kotscyi, as indicated by higher chiasma frequency per pollen mother cell. Significant reduction in frequency of univalents and increase in bivalents (>14), multivalents, and chiasma frequency in crosses of amphiloids with CS(Ph') as compared to those of CS indicated homoeologous pairing between C and D, D and U, and C, D, and U genomes with AB genomes in the presence of Ph'. The results of the present study unequivocally demonstrate the effectiveness of Ph' gene transferred from Ae. speltoides in hexaploid wheat in inducing homoelogous chromosome pairing and suggest that the line CS(Ph') can be effectively used for precise transfer of useful alien genetic variations with least linkage drag.