Genetic and agronomic studies of non-elongating sub-crown internode in spring barley (Hordeum vulgare L.)

his dissertation reports on studies of non-elongating subcrown internode (NE) in spring barley and its role in plant performance under reduced water use. Chapter 1 covers the inheritance study of NE. Chapter 2 reports a two year study of seeding depth and subcrown internode length (SIL) effects in performance of barley, wheat and durum genotypes. Chapter 3 reports on genetic and environmental factors that affect crown depth and crown root development under a one-irrigation cultural regime. The research was conducted between 1990 and 1993 under field and greenhouse conditions.;The NE character appears to be controlled by a major recessive gene. Selecting the NE trait is relatively easy by conventional plant breeding. SIL variation is continuous and seems regulated by several modifiers that interact strongly with the environment. Expression of genes for SIL require deep seeding.;Under field conditions and regardless of genotype, shallow seeding inhibited SIL but produced shallow crowns while deep seeding stimulated SIL but produced deeper crowns. Deep seeding increased yield, 100-seed weight, seeds/spike, an days to anthesis, but reduced tillers/m;The time of crown root initiation varied tremendously among barley plants of CC XXXIX. Crown roots/plant could be predicted by leaves/plant (r = 0.92; P...