J. M. Ramos

Integration of statistical and physiological analyses of adaptation of near-isogenic barley lines

Seven near-isogenic barley lines, differing for three independent mutant genes, were grown in 15 environments in Spain. Genotype x environment interaction (G x E) for grain yield was examined with the Additive Main Effects and Multiplicative interaction (AMMI) model. The results of this statistical analysis of multilocation yield-data were compared with a morpho-physiological characterization of the lines at two sites (Molina-Cano et al. 1990). The first two principal component axes from the AMMI analysis were strongly associated with the morpho-physiological characters. The independent but parallel discrimination among genotypes reflects genetic differences and highlights the power of the AMMI analysis as a tool to investigate G x E. Characters which appear to be positively associated with yield in the germplasm under study could be identified for some environments.

Image Analysis of Grain and Chemical Composition of the Barley Plant as Predictors of Malting Quality in Mediterranean Environments

ABSTRACT We have explored the possibility of predicting the malting quality of barley grain, indicated by malt extract yield, by characteristics measured either on plants at anthesis or in mature dry grain by image analysis. To produce barley samples with varying levels of all the characteristics studied, we used grain from an experiment designed to study the influence of lowinput husbandry practices on malting quality of barley by growing five malting genotypes at each of four environments (site × season) and with two different agronomic treatments (N fertilization and herbicide-mechanical roguing of weeds). The results showed that nitrogen content in the plant at anthesis was a good predictor of grain protein content, this characteristic in turn being positively correlated with embryo size and grain volume, as estimated by image analysis, and negatively correlated with nonstructural carbohydrate content in the plant at anthesis. Extract yield was positively correlated with Kolbach index (ratio of solubl...

Barley response to nitrogen rate and timing in a Mediterranean environment

Nitrogen is an important factor determining grain yield of barley ( Hordeum vulgare L.). Optimal rates and application timing can vary according to the environmental conditions under which the crop is grown. For 8 years (1979–86) barley yield, tillering, and leaf-area response to N application rates and timing were studied in southern Spain. The results showed that, under our experimental conditions, the most advantageous N rate for grain yield was 60 kg/ha, either split equally between sowing and tillering, or else with the greater proportion applied at tillering. Nitrogen applied at sowing increased number of tillers per plant, and N applied at tillering favoured tiller survival for later spike formation. In addition, N applied at tillering increased the number of leaves per plant, leaf area per plant, and the leaf area index, the maximum value of which occurred at anthesis.

Apex and ear development in relation to the number of grains on the main-stem ears in spring barley (Hordeum distichon)

Apex and ear development in nine spring barley genotypes were studied at two sites in southern Spain in 1988. The genotypes were grouped into medium and early types, depending on the time from sowing to anthesis. Medium genotypes had significantly more spikelet primordia than early ones at both sites. Spikelet mortality was similar between genotypes and sites, resulting in a higher final number of grains/ear in the medium than the early genotypes.There was a positive correlation between the maximum number of spikelet primordia and the duration of three stages of apical development: lemma-, stamen- and awn-primordia. Negative correlations were observed between spikelet mortality and the duration of certain developmental phases of the ear.

Quantitative phenotypical expression of three mutant genes in barley and the basis for defining an ideotype for Mediterranean environments.

SummaryThree mutants induced in the two-rowed barley variety Beka and their three binary recombinants have been used in an attempt to define an ideotype suitable for Mediterranean agroclimatic conditions. Physiological methods (classical plant growth analysis) together with the study of genotype x environment interaction for grain yield were used to characterize the genotypes. That characterization brought out the huge phenotypical variation produced by only three mutant genes, suggesting that single Mendelian genes may alone explain the quantitative variation, including grain yield, without the necessity of using the polygenic concept. The genotype best adapted to the environments studied is later in heading and has shorter straw and denser spikes than Beka; it also has higher inverse of leaf area rate and grain: leaf area ratio, a lower rate of leaf senescence, and a shorter grain filling period than the original variety.

Grain yield, biomass and leaf area of triticale in response to sowing date and cutting stage in three contrasting Mediterranean environments

The effects of sowing date and cutting stage on grain yield, biomass and leaf area were analysed in three spring triticale genotypes (× Triticosecale Wittmack) grown at three different sites in Spain during 1990/91. Results indicated that the most appropriate sowing date for grain yield in these environments seemed to be from the last 10 days in November to mid-December. Cutting reduced grain yield, biomass and leaf area at anthesis, and these decreases were greater in a drier environment (the only exception being cutting at Zadoks growth stage (GS)31 at Lleida), and when the cutting was done at GS31 rather than GS30. The significant relationships found between the percentage loss in grain yield and biomass and leaf area at anthesis after cutting suggest that genotypes intended for grain and forage production need to be able to regenerate leaf area rapidly after cutting.

Apical Development in Triticale Grown for Dual Purpose in a Mediterranean Environment

Apical development in three triticale varieties grown for dual use (forage and grain) was studied in southern Spain during 1991. Three treatments were compared: CO, an uncut control; C30, one cutting made at Zadoks’ stage 30 (pseudo stem erection); and C31, one cutting made at stage 31 (first node detectable). The cuttings significantly delayed the terminal spikelet stage, this effect being more pronounced after cutting at stage 31. The treatments, however, significantly reduced the duration from this last stage to the anthesis. The number of primordia at the terminal spikelet stage, anthesis and physiological maturity, was only significantly diminished after C31 treatment. The forage removal reduced the rate of spikelet initiation, the lowest values obtained from C31 treatment. The spikelet losses from the terminal spikelet stage to maturity were significantly higher in the treatment C30.