No description available.

This project involved two locations (Breda and Tel Hadya) over two seasons (1993 and 1994). Yield was found to have been affected by many factors including environment, genotype and morphological characters. A genotype-environment interaction (GEl) was also discovered. To investigate the influence of morphological characters on yield parameters, multivariate statistical techniques (canonical analysis, factor analysis and multiple regression analysis (linear and exponential)) were used. Multivariate statistical techniques were applied to three hybrids (Hybrid 1, 2 and 3) in replicated field plots at two locations (Breda and Tel Hadya) in two seasons. Canonical analysis and factor analysis revealed a significant relationship between yield parameters and morphological characters. However, this relationship was not significant for each hybrid because there were insufficient data for each hybrid. Stepwise multiple regression analysis showed that plant height, vegetative duration and length of growing season were the significant factors influencing yield parameters, while leafiness was not. The relationship can approximate nonlinear in that it gives more realistic predictions. Consequently, stepwise multiple exponential equation fitted the data better than stepwise multiple linear equation. The relationship between yield parameters and morphological characters was affected by environment but not by genotype.

No description available.

Naked, or hull-less, barley is gaining increased interest for human consumption because of its free-threshing habit (lowering processing costs and avoiding loss of bran during pearling) and higher f3-glucan (soluble fibre) content, implicated in lowering glycaemic index. The naked seed trait is coded by a single recessive gene, nud, where the palea and lemma do not adhere to the caryopsis. However, a persistent problem with naked barley is poor establishment in typical British cool, damp late winter sowing conditions. It was hypothesized that this was due to short coleoptile length in the few European varieties that possess the naked seed trait (most European barleys being hulled). However, the naked trait is widespread in those nations where barley forms a significant component of human diet such as Ethiopia and Central Asia, but where growing conditions are often harsh. Germination and establishment characteristics of several lines from these areas were tested in the field, cold room and glasshouse. Coleoptile length was found to vary significantly between genotypes and was correlated with successful establishment. However, many exotic genotypes have agronomic traits which are poorly adapted to British growing conditions, such as low disease resistance, unduly short or long duration, lax leaf habit and weak straw. The genotype with the longest coleoptile length, Tibet-37, was crossed with Taiga, a cultivar from Germany which has a short coleoptile and poor field establishment. From this cross a mapping population was produced using the single seed descent method by uni-culm micro plant. 145 recombinant inbred lines (RILs) were produced from which 68 were black, 47 grey and 30 were white seeded. Among these black colour and grey colour lines were true hybrids. However, white testa lines were doubtful; their performance was similar to the Taiga parent. Coleoptile length was fOUnd to be heritable in the progeny. Using the rapid micro-plant technique, it was POssible to advance to the F6 generation within two years. F7 RILs were phenotyped in the glasshouse as a first stage in genetic mapping, and the F8 RILs were field tested for coleoptile length and seedling emergence characteristics. Results show that coleoptile length is a continuously variable trait with Tibet-37 and Taiga at the upper and lower ends of the range, respectively. CL showed significant correlation between field and cold room experiment. Seed colour was significantly associated with CL, EP and SE. The black testa colour RILs showed highest CL length hence, it is concluded that black seed colour might be linked with long coleoptile traits and a good morphological marker for coleoptile length and establishment in this population.

In Orkney, Bere (a landrace of barley) is traditionally cultivated in marginal areas with very low inputs. There was little information on the effects of different agricultural inputs on Bere. Therefore this research investigated the effects of nitrogen, fungicide and plant growth regulator on grain yield, quality and economic returns of Bere which were compared with Optic (a modern malting barley variety) during 2008 and 2009. The present study found that ears m-2 and 1000-grain weight were two important components responsible for yield variations between Bere and Optic and were consistently lower in the former than the latter. The results indicated that disease score, lodging index and grain nitrogen content were higher in Bere than Optic, and the former had more stable yield than the latter during the study period. Increasing nitrogen fertilizer rate enhanced ears m-2 and grain yield of both varieties. However, the highest N rate (90 kg ha-1) resulted in the highest disease score and lodging index which consequently reduced grain quality of Bere. Fungicide application at Zadoks growth stage 37 reduced disease score and enhanced grain yield of both varieties compared with control plots and this was attributed to higher ears m-2 and 1000-grain weight. The plant growth regulator Upgrade (mixture of ethephon and chlormequat chloride) applied at the recommended rate at Zadoks growth stage 31 resulted in the lowest lodging index in Bere. However, it had no significant effect on grain yield and grain nitrogen content of both varieties. Gross margin analysis indicated that Bere compared favourably with Optic due to its higher grain price. Although, plant growth regulator did not justify its expenditure for controlling lodging, its application is recommended to ease harvesting and to avoid pre-harvest yield and quality losses in Bere.

Some physiological effects of freezing and flooding were studied on winter barley (Hordeum vulgare L.). The effects of freezing on plants grown under field conditions were determined by comparing plants exposed to naturally-occurring freezing temperatures with plants protected from such temperatures by thermostatically-controlled soil heating cables. The results from field trials in 1982/83 and 1983/84 showed the effects of freezing to include: (i) A reduction in the establishment of late-sown plants due to soil heaving. (ii) A retardation of plant and apical development. (iii) Occasional transient reductions in above ground dry matter and leaf area. (iv) Variable effects upon certain yield components. Attributes not greatly affected by such temperatures included cold hardiness and yield on a per plant basis. Controlled environment studies showed that non-lethal freezing temperatures ranging from -4 to -10oC significantly reduced shoot photosynthesis and dark respiration, the greater reductions being in photosynthesis. Factors involved in these reductions include damage to leaves and roots, neither of which were critical for plant survival. When a conductivity method was used to estimate the damage to different plant parts resulting from extracellular freezing, leaf laminae were found to be more freezing tolerant than roots, and young laminae were more tolerant than older laminae. Some effects of flooding were also studied using controlled environments, and cultivar differences in flooding tolerance were found. This tolerance was investigated by comparing the response to flooding of a tolerant cultivar (Athene) with a sensitive one (Maris Otter). Flooding sensitivity was shown as wilting in the leaves of Maris Otter, the onset of wilting being associated with the leakage of electrolytes and accumulation of ethanol in the leaf laminae. The results of exogenous application of ethanol to leaves, suggest the basis of this `tolerance' is ethanol exclusion. The production of aerenchyma was not associated with flooding tolerance.

Bibliography: leaves 114-141. / vi, 141, [42] leaves, [19] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Using RFLP, STS-PCR and isoenzyme techniques, maps the structural genes of hydrolytic enzymes important in seed germination processes, and determines the contribution of each gene to the activity of the enzyme. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1998

Errata attached to inside front cover. / Bibliography: leaves [156-188] / vi, 155, [33] leaves, [48] leaves of plates : ill. (some col.) ; 30cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 2001