The effects of Hordeum spontaneum C. Koch. germplasm on barley production

Abstract

The cytoplasmic genome affects both physiological and agronomic traits in many crop species. It can affect a trait directly or by in­ teracting with the nuclear genome. The objectives of this study were to (1) determine whether Hordeum vulgare L. and H. spontaneum C. Koch, cyto­ plasmic genomes differentially affect grain yield, straw yield, harvest index, plant height, unit straw weight, heading date, and vegetative growth index, (2) determine whether nuclear-cytoplasmic genomic inter­ actions occur, and (3) ascertain the nature of nuclear cytoplasmic inter­ actions. Eighty-four populations of 14 lines each, representing recipro­ cal crosses of the SCO, BCl, and BC2 generations from all possible matings among seven H. spontaneum and two H. vulgare cultivars were evaluated in the field in two years. Cytoplasmic effects were significant for grain yield, straw yield, harvest index, unit straw weight, and vegetative growth index. Lines with H. spontaneum cytoplasm had greater means for straw yield, unit straw weight, and vegetative growth index than did lines with H. vulgare cytoplasm. Conversely, lines with H. vulgare cytoplasm showed a greater mean grain yield and harvest index. Cyto­ plasmic effects were consistent through backcross generations for straw yield, unit straw weight, and vegetative growth index; however, cyto­ plasmic effects did interact with generations for grain yield and har­ vest index. Cytoplasm x mating interaction was significant in all gen­ erations for straw yield but only in the BC2 for unit straw weight and vegetative growth index, indicating specific nuclear-cytoplasmic genomic