Graca Pereira

Morphological characterization of a small common bean (Phaseolus vulgaris L.) collection under different environments

There is a long tradition in the cultivation of pulses in the Balkans and the Iberic Peninsula, mainly used for human consumption. Among the major food legumes common bean is the most important. A large range of landraces are still grown that have adaptation to local climatic conditions and resistance or tolerance to diseases and pests allowing high yield stability under a low input farming. The main purpose of this work was to analyze the morphological variability of 15 Portuguese and 15 Bulgarian landraces in different environmental conditions (in Bulgaria and Portugal) in order to generate information that can help identifying the most suitable resources with good adaptability to different environments. The landraces were evaluated for 16 morphological characters. A considerable morphological variation was found among genotypes. The majority of landraces had white seeds colour but some had also cream, purple and white with red colours around the hillum. The predominant seed shape was long but three accessions have round shape. The geographical site of the trials (Elvas, Portugal or Sadovo, Bulgaria) determined the cluster pattern of the majority of accessions. In Portugal, the plants required more days to reach the flowering and maturity phases and had higher biological yield. In both environments, the components that mainly determined yield were the number of pods and the number of seeds per plant. The highest value for these traits were found in one Portuguese accession (cat.№ PH2) and one Bulgarian accession (cat.№ 99E0128), in both experimental conditions.

Genotype by environment interactions in cowpea (Vigna unguiculata L. Walp.) grown in the Iberian Peninsula

Abstract. The aim of this work was to determine the variance components and genetic and environmental stability of 12 cowpea genotypes at three locations (South-east of Spain: Cartagena, South and North of Portugal: Elvas and Vila Real, respectively) in the Iberian Peninsula in two consecutive years (2015 and 2016). The genotype, the environment and the genotype × environment interaction significantly influenced all the morphological and agronomical parameters evaluated. For both years, the highest yields were observed at Elvas, whereas Cartagena and Vila real were the most suitable places to obtain crop precocity. Cartagena was the place where the filling of the seed was the fastest, probably due to the higher temperatures and radiation. The thermal time model (effective degree-days) could be used to predict the period of cowpea development, therefore predict flowering and pod maturity date. Correlation analysis showed that days to flowering, days to maturity and the seed yield vs protein content exhibited negative correlations. The highest heritability was found for plant height and pod length at Cartagena and for 100-seed weight at Elvas and Vila Real. In conclusion, the variations that exist in the studied accessions could give rise to a breeding program to develop cowpea cultivars with interesting agronomic traits.