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Cowpea Plant Architecture in Relation to Infestation and Damage by the Legume Pod Borer, Maruca Testulalis Geyer (Lepidoptera: Pyralidae) — 2. Effect of Pod Angle

  • S. Oghiakhe
  • L. E. N. Jackai
  • W. A. Makanjuola
Research Article

Abstract

The effect of pod angle on the resistance of cowpea, Vigna unguiculata (L.) Walp. to the legume pod borer, Maruca testulalis Geyer, was investigated under field conditions at the International Institute of Tropical Agriculture (UTA), Ibadan, Nigeria, using two cowpea cultivars: IT82D-716 (susceptible to borer damage) and T Vu 946 (resistant to borer damage). Three different pod angles were used In the study — a normal angle, a decreased angle and an increased angle. Negative and highly significant (P < 0.01) relationships were found between pod angle and per cent pod damage, as well as the seed damage Index In the two cowpea cultivars. Pods with wide angles ( ≥ 89°) were damaged on only one and rarely on both pods. Apart from biochemical and other bio-physical factors, selection and breeding for wide pod angle is suggested as a strategy for reducing M. testulalis damage to cowpea pods.

Key Words

Pod angle Marucatestulalis resistance cowpea Vigna unguiculata plant architecture 

Résumé

L’effet de l’angle des gousses sur la résistance du niébé, Vigna unguiculata à la foreuse des gousses, Maruca testulalis a été étudié en champ à l’institut international d’agriculture tropicale (UTA), Ibadan (Nigeria) sur deux cultivars de niébé: IT82D-716 (sensible) et TVu 946 (résistant). Trois angles différents des gousses ont été étudies: angle fermé, angle normal et angle ouvert.

Des relations négatives hautement significatives (P < 0.01) furent observées entre l’angle des gousses, le pourcentage de dégâts sur les gousses et l’indice de dégâts sur les graines chez les deux cultivars. Dans l’ensemble, pour les gousses à angle ouvert (>89°), M. testulalis a occasionné des dégâts sur une seule gousse par plant.

La sélection et l’amélioration du niébé pour l’obtention de gousses à angle ouvert ont été suggérées comme moyen de réduire les dégâts de M. testulalis sur les gousses de niébé.

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Copyright information

© ICIPE 1992

Authors and Affiliations

  • S. Oghiakhe
    • 1
  • L. E. N. Jackai
    • 1
  • W. A. Makanjuola
    • 2
  1. 1.International Institute of Tropical Agriculture (IITA)IbadanNigeria
  2. 2.Department of Biological SciencesUniversity of LagosAkoka-YabaNigeria

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