Screening amaranth genotypes ("Amaranthus" spp.) for yield and resistance to leaf blight caused by "Rhizoctonia solani" Kuhn.

espanolLos cultivos vegetales de amaranto de Kerala estan amenazados por la mancha foliacea provocada por Rhizoctonia solani. En la Escuela Superior de Agricultura Vellayani de Trivandrum, India, se evaluaron en condiciones de campo seis accesiones de amaranto (Amaranthus spp.) recogidas de diferentes lugares, incluidos parientes silvestres, a fin de encontrar genotipos de alto rendimiento y resistentes a la mancha foliacea provocada por Rhizoctonia solani. Los genotipos se clasificaron con arreglo a una escala de 0 a 7 relativa al grado de dano en las hojas. La accesion A 57 registro el rendimiento mas elevado (304,5 g/ planta). El genotipo A24 perteneciente a A. tricolor registro la mayor relacion hoja:tallo de 1,57. Cuatro accesiones de A. dubius, a saber A 22, A 26, A 29 y A 61 eran completamente resistentes a la mancha foliacea y podran ser utilizadas para ulteriores mejoramientos. EnglishVegetable amaranth cultivation in Keralais hampered by leaf blight caused by Rhizoctonia solani. Sixty amaranthus (Amaranthus spp.) accessions, including wild relatives, collected from different sources, were evaluated under field conditions at the College of Agriculture, Vellayani, Trivandrum, India, to locate genotypes with high yield and resistance to leaf blight caused by Rhizoctonia solani. The genotypes were scored for leaf blight incidence on a O to 7 scale for extent of leaf damage. The highest yield was recorded by accession A 57 (304.5 g/plant). The genotypeA24 belonging to A. tricolor recorded the maximum leaf:stem ratio of 1.57. Four accessions of A. dubius, namely A 22, A26, A29 and A61, were completely resistant to leafblight and could be used for further breeding. Key words: Screening, amaranth, yield, disease resistance francaisLa culture maraichere de l'amarante au Kerala est affectee par Rhizoctonia solani qui provoque une brulure fongique sur les feuilles. Soixante accessions d'amarante (Amaranthus spp.), incluant des especes sauvages apparentees de differentes sources, ont ete evaluees dans des essais en champ au College of Agriculture, Vellayani, Trivandrum, Inde, afin de localiser des genotypes caracterises par un rendement et une resistance elevee a la brillure des feuilles provoquee par Rhizoctonia solani. L'importance des dommages foliaires sur les differents genotypes a ete evaluee sur une echelle de o a 7. Le rendement le plus eleve a ete observe dans le cas de l'accession A 57 (304,5 g/plante). Le genotype A24 appartenant a A. tricolor presente le rapport feuille:tige le plus eleve (1,57). Quatre accessions de A. dubius, A22, A26, A29 et A61, sont totalement resistantes a la brulure des feuilles et peuvent etre utilisees dans de futures programmes de selection.