Intercropping of Faba Bean with Barley at Various Spatial Arrangements Affects Dry Matter and N Yield, Nitrogen Nutrition Index, and Interspecific Competition

Intercropping is the cultivation of two or more crop species on the same area of land, and can improve yield, forage quality, and soil health. Despite the fact that intercropping is an old practice, it received significant attention the last years because of the environmental impact that it has. However, the effect of the various spatial arrangements of the different species that are used in an intercropping system was not determined. The objective of the present study was to study the yield, growth and nitrogen (N) uptake rate, N nutrition index (NNI) of barley, interspecific competition, quality and financial outcome of intercrops of faba bean (Vicia faba L. var. equina) and barley (Hordeum vulgare L.) with various spatial arrangements (1:1, 2:2, 2:1 alternate rows, and mixed in the same row). The land equivalent ratio (LER), relative crowding coefficient (K), actual yield loss (AYL) and system productivity index (SPI) values were greater for the FB:B intercrop of 2:1, indicating the advantage of intercropping in terms of dry matter and N yield. Sole cropping of barley showed a reduction in NNI by 7 %, whereas NNI for barley increased by an average of 14% in intercropping treatments. Based on biomass production and the competition indices for dry matter and N yield, and NNI the FB:B intercrop of 2:1 was more advantageous than faba bean and barley monocrops, as well as the other intercropping treatments that were tested

Evaluation of physiological characteristics as selection criteria for drought tolerance in maize inbred lines and their hybrids

Improvement for maize drought tolerance has always been a significantobjective for breeders and plant physiologists. Nowadays, climate change sets new challenges to major crop adaptation at stressful environments. For such a purpose, the measurement of physiological traits related to maize response to drought might prove to be useful indices. The objective of the present study was to establish whether the physiological traits can be used as reliable physiological markers to evaluate the performance of parental genotypes and their hybrids under both dry and normally watered conditions, and under two densities an ultra-low density (ULD) and a normal dense stand (DS). Thirty (30) maize inbred lines and 30 single-crosses among them were evaluated across three diverse locations in Greece. The ULD was 0.74 plants/m-2, while the DS comprised 4.44 plants m-2 in the water deficitregime, and 6.67 and 7.84 plants m-2 in the normal water treatment for lines and hybrids, respectively. There was a very good association between the physiological characteristics studied and grain yield under the ultra-low density and especially for inbred lines. It was shown that the physiological characteristics can facilitate the selection of stress-adaptive genotypes under the low-density conditions and may permit modern maize to be grown at a wider range of environments. At the normal densities such a possibility was not evidenced since physiological parameters and yield did not correlate for either parents or hybrid

Comunicación corta. Efecto de la densidad de la plantación en la variabilidad planta a planta del rendimiento expresado como coeficiente de variación en cebada

The effect of plant density on the coefficient of variation (CV) for individual plant yield was studied in barley (Hordeum vulgare L.). An F2 population originating from the cross Niki x Carina was planted in three densities: high (51.32 plants/square m), intermediate (4.61 plants/square m), and low (1.15 plants/square m) using the honeycomb design. In each of the experiments, the most promising 15 plants were selected based on the individual plant yield. Progeny (F3) of the 30 plants selected from the intermediate and the low plant density were grown the following year in two experiments under an intermediate and low density. It was observed that in the F2 population the CV was reduced from 71 to 55% when the density reduced from 51.32 to 4.61 plants/square m, whereas the CV value was increased when the density was further reduced to 1.15 plants/square m. Similarly, the following year the CV was increased from 39 to 56% when the density was decreased from 4.61 to 1.15 plants/square m in the F3 generation, and from 22 to 58% in the control. It was concluded that for barley an optimum plant density might exist under which the CV for individual plant yield is minimized and therefore the effectiveness of selection might be optimized.Se estudió en cebada (Hordeum vulgare L.) el efecto de la densidad de plantación en el coeficiente de variación (CV) del rendimiento individual de la planta. Se plantó una población F2 originada desde el cruce Niki x Carina en tres densidades: alta (51,32 plantas/m cuadrado), intermedia (4,61 plantas/m cuadrado), y baja (1,15 plantas/m cuadrado) utilizando un diseño en colmena. En cada uno de los experimentos se seleccionaron las 15 plantas con mayor potencial según el criterio de rendimiento de planta individual. La descendencia (F3) de las 30 plantas seleccionadas de zonas de densidades baja e intermedia se cultivó el año siguiente en dos experimentos en condiciones de densidad intermedia y baja. Se observó que en la población F2 el CV se redujo desde 71 al 55% cuando la densidad bajó de 51,32 a 4,61 plantas/m cuadrado, mientras que el valor del CV aumentó cuando se redujo aún más la densidad, a 1,15 plantas/m cuadrado. De forma similar, el año siguiente el CV aumentó de 39 a 56% cuando la densidad bajó de 4,61 a 1,15 plantas/m cuadrado en la generación F3 y de 22 a 58% en el control. Se concluye que, para cebada, podría existir una densidad de plantación óptima bajo la cual el CV del rendimiento individual se minimiza y, por tanto, la efectividad de la selección se puede también optimizar

Evaluation of faba beans for resistance to sclerotinia stem rot caused by Sclerotinia trifoliorum

Sclerotinia stem rot, a fungal disease caused by Sclerotinia trifoliorum, is often a serious problem in faba beans (Vicia faba). The levels of resistance to sclerotinia stem rot were evaluated in 23 faba bean cultivars originating from various European countries, 18 cultivars from ICARDA, five cultivars from Canada, 58 populations originating from various provinces of Greece, and five V. narbonensis populations. Evaluation was done under controlled conditions following artificial inoculation with carrot root pieces colonized by the fungus. Faba bean plants were scored for resistance on a 0 to 3 severity scale. There was significant variability for resistance to S. trifoliorum among faba bean cultivars and among populations. Seven cultivars and 15 Greek faba bean populations showed a satisfactory level of resistance (≤ 1.50), whereas 22 cultivars and 25 populations were susceptible (> 2.00). However, all V. narbonensis populations were resistant to S. trifoliorum (disease severity from 1.11 to 1.44) without significant variability within populations. Variability in the resistance of faba beans to S. trifoliorum would allow selection within appropriate genotypes for breeding in an effort to provide an effective alternative for sclerotinia stem rot management in this crop.La pourriture à sclérotes, une maladie fongique causée par le Sclerotinia trifoliorum est souvent un grave problème pour la production de féverole (Vicia faba). À la suite d’une inoculation artificielle avec des morceaux de carottes colonisés par le champignon, l’intensité de la résistance à la pourriture à sclérotes a été évaluée en conditions contrôlées chez 23 cultivars de féverole provenant de divers pays européens, 18 cultivars de l’ICARDA, cinq cultivars canadiens, 58 populations issues de diverses provinces de Grèce et cinq populations de V. narbonensis. Une cote de résistance a été attribuée à chaque plante sur une échelle d’intensité de maladie allant de 0 à 3. Il y avait des différences significatives pour la résistance au S. trifoliorum parmi les cultivars et parmi les populations de féverole. Sept cultivars et 15 populations grecques de féverole ont démontré un degré satisfaisant de résistance (≤ 1,50), alors que 22 cultivars et 25 populations étaient sensibles (> 2,00). Par contre, toutes les populations de V. narbonensis ont été résistantes au S. trifoliorum (intensité de maladie entre 1,11 et 1,44) sans qu’il n’y ait de différence significative entre les populations. Les différences de résistance au S. trifoliorum dans la féverole signifient qu’il serait possible de procéder à de la sélection au sein de génotypes choisis afin d’offrir l’amélioration génétique comme moyen efficace de lutte contre la pourriture à sclérotes de cette culture

MODELLING YIELDS OF NON-IRRIGATED WINTER WHEAT IN A SEMI-ARID MEDITERRANEAN ENVIRONMENT BASED ON DROUGHT VARIABILITY

Regression models for the prediction of grain yields of non-irrigated winter wheat in a semi-arid Mediterranean environment were developed based on drought variability. Twenty-five years (1980-2004) of climate data and yield data from four soils (sandy loam, clay, clay loam and sandy clay loam soil) in northern Greece were used for this purpose. Two variables were selected as explanatory variables of the models: (a) the monthly precipitation versus the monthly reference evapotranspiration ratio (P/ETo ), which describes the monthly drought and consequently the water deficit conditions during the wheat-growing season and (b) the mean observed yield ( y) of each soil, which indirectly describes the intrinsic fertility of the soils. A resampling technique using subsets of the data (bootstrapping) was applied to estimate the coefficients of the models, to assess the uncertainty of the selected explanatory variables and to validate the models. The models showed adequate predictive ability of wheat yields, defining the time and intensity of drought effects. The most crucial period for winter wheat was found to be primarily the vegetative-reproductive stage period between late winter and mid-spring (i.e. February to April). Soil clay content was found to be the most representative parameter in describing most of the physico-chemical parameters and properties of the soils and consequently the mean yield, indicating that yield is non-linearly correlated with most soil properties. With the proposed models, yield gap (YG) predictions between two growing seasons of the selected soils presented 84% accuracy in all years in the identification of the correct signal (+ or -) of yield increase or decrease, respectively, and adequate performance in the prediction of the mean YG