In this study 384 Turkish originated oat genotypes obtained from different gene banks, were characterized and evaluated for agronomical traits with four commercial cultivars (Checota, Sebat, Faikbey and Seydişehir) under augmented experiment design for 2012-2013 and 2013-2014 cropping years. Oat landraces were evaluated for stem diameter (SD), plant height (PH), panicle length (PL), vegetative period (VP), grain filling period (GFP), days to maturity (DM), grain number per panicle (GNP), grain weight per panicle (GWP), thousand kernel weight (TKW), lodging (LOD), barley yellow dwarf virus (BYDV) and single row yield (SRY) under Kahramanmaraş conditions. According to the results of field trail for two years, differences of genotypes were significant for SD, PH, PL, VP, DM, TKW and SRY. However, the components such as SD, PL, VP, GFP, DM, GNP, GWP, TKW and SRY were significantly changed for the years and year x genotype interactions were also significant for PL, VP, DM, TKW and SRY. The landraces performed better than the commercial ones for the most of the evaluated traits. The SRW ranged between 4.65 g (TL444) to 202.1 g (TL614). Moreover, the other genotypes with the higher SRY were TL708, TL714, TL734 and TL703 genotypes with 167.85, 160.25, 153.90 and 149.7 g SRY, respectively.

In order to investigate diversity and explain the relationships of essential oil yield with morphological traits, 84 populations T. polycephalum, were sown in the field using randomized complete blocks design (RCBD) with three replicates in Research Institute of Forest and Rangeland, Tehran, Iran in 2013-2014. Data were collected for flowering date, growth degree days (GDD), stem number, plant height, dry matter (DM) yield, essential oil percentage, and essential oil yield. The relationships among traits were determined using correlation, regression and factor analysis. The genetic distance and genotype classification were determined using cluster analysis. DM yield was positively correlated with plant height, canopy cover, stem number and oil yield (ρ<0.01), whereas oil% was negatively correlated with plant height and stem number (ρ<0.05). Result of stepwise regression in which essential oil yield were considered as dependent variable showed that essential oil%, and DM yield accounted for 39.95 and 47.75%, of the total variations in essential oil production, respectively. In factor analysis, the Eigen values obtained from 1 to 3 factors were higher than one with 88.9% of total variations. In the first factor, traits of DM yield, plant height, canopy cover, stems number, and in the second factor flowering date, GDD and oil yield and in the third factor oil% had higher Eigen vector coefficients for genotype classification. In cluster analysis, genotypes were categorized in four groups. According to the obtained results, cluster 1 for early maturity, clusters 3 for plant height canopy cover, stems number, DM yield and essential oil production and cluster4, for essential oil%, had significantly higher mean values than other groups. There was a good agreement between the results obtained from cluster and factor analyses in scatter diagram representation of 84 genotypes based on the first and second factors. It was concluded that population of cluster 3 are capable to breeding improved new cultivars and should be focused on selection higher aerial biomass yield, plant height, flower number, essential oil%, coupled with early flowering date. | Para investigar la diversidad y explicar las relaciones del rendimiento de aceite esencial con rasgos morfológicos, 84 poblaciones de T. polycephalum fueron sembradas en el campo utilizando diseño de bloques completos al azar (BCA) con tres réplicas en el Instituto de Investigación de Bosques y Pastizales, Teherán, Irán en 2013-2014. Los datos fueron colectados para la fecha de floración, días de grado de crecimiento (DGC), número de tallos, altura de planta, rendimiento de materia seca (MS), porcentaje de aceite esencial y rendimiento de aceite esencial. Las relaciones entre las características agronómicas se determinaron mediante correlación, regresión y análisis factorial. La distancia genética y la clasificación del genotipo, se determinaron mediante análisis de conglomerados. El rendimiento de MS se correlacionó positivamente con la altura de la planta, cobertura del dosel, número de tallos y rendimiento de aceite (ρ <0.01), mientras que el% de aceite esencial se correlacionó negativamente con la altura de la planta y el número de tallos (ρ <0.05). El resultado de la regresión gradual en la cual el rendimiento de aceite esencial se consideró como variable dependiente mostró que el% de aceite esencial y el rendimiento de MS representaron 39.95 y 47.75% de las variaciones totales en la producción de aceite esencial, respectivamente. En el análisis de factores, los valores de Eigen obtenidos de 1 a 3 factores fueron mayores que uno con 88.9% de las variaciones totales. En el primer factor, los rasgos de rendimiento de MS, altura de la planta, cobertura del dosel, número de tallos y en la segunda fecha de floración del factor, DGC y producción de aceite esencial y en el tercer factor, % de aceite esencial, tuvieron coeficientes de vectores Eigen más altos para la clasificación del genotipo. En el análisis de conglomerados, los genotipos se categorizaron en cuatro grupos. De acuerdo con los resultados obtenidos, el grupo 1 para madurez temprana, los grupos 3 para cobertura vegetal del dosel, el número de tallos, el rendimiento de MS y la producción de aceite esencial y el grupo 4, para% de aceite esencial, tuvieron valores promedio significativamente más altos que otros grupos. Hubo una buena concordancia entre los resultados obtenidos de los análisis de grupos y factores en la representación del diagrama de dispersión de 84 genotipos en función del primer y el segundo factor. Se concluyó que la población del grupo 3 es capaz de producir nuevos cultivares mejorados y debe centrarse en la selección de mayor rendimiento de biomasa aérea, altura de la planta, número de flores, % de aceite esencial, junto con la fecha de floración temprana.