THE BASIS OF LOW GRAIN-YIELD AND INFERTILITY IN AUTOTETRAPLOID BARLEY (HORDEUM-VULGARE)

Under spaced plant conditions the grain yield of autotetraploid forms of two barley cultivars were shown to be less than half that of their diploid counterparts despite an increase in grain size. Lower yield was due to fewer tillers, fewer florets per spike and lower floret fertility. Nevertheless, it is concluded that incomplete seed set remains the main constraint to the utilization of tetraploid barley. The basis of infertility was examined at both pre and post fertilization stages. Genetic imbalance in aneuploid gametophytes, although a contributory factor, was ruled out as the sole cause of infertility. Non-fertilization of egg cell or polar nuclei and abortion of embryo and/or endosperm during early embryogenesis were also identified as contributing to loss of fertility. © 1990 The Genetical Society of Great Britain.