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Physiological response of groundnut to plant population density Tarimo, J.P. Akwilin Abstract Two experiments were carried out in two seasons at the University of Queensland, Redland Bay Farm in Southeast Queensland, Australia to identify some physiological determinants of groundnut response to plant population density after anthesis. The first experiment was grown in square spacings while the second one was grown in rectangular spacings. Yield componet analysis (YCA) techniques were used to study the yield and yield component responses to the different levels of plant population density. The results show that variation in kernel yield m-2 among the plant population densities was associated with responses of some reproductive yield components, e.g. kernel mass (KDM/Nk) to the plant population densities. In contrast, the responses of vegetative components to those densities had little association with the overall kernel yield differences in this study. It is concluded that the two-dimensional partitioning (TDP) technique of YCA provides an effective method of identifying physiological and morphological determinants of yield variation in groundnut under field conditions. From the results, variation in kernel dry matter production was associated with responses of KDM/NK, Npg/Al, NPG, NK/NP and NB/N to the treatments. Keywords Arachis hypogaea L., lernel dry matter, plant population density, two-dimensional partitioning, yield components

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Tarimo, J.P. Akwilin Résumé Deux experimentations ont ete menees pendant deux campagnes a l'Universitede Queensland, Redland Bay Farm au Sud-est de Queensland, en Australie afin d'identifier quelques determinants physiologiques de la reaction de l'arachide a la densite de la population des plantes apres l'anthese. La premire experience etait menee aux ecartements carres tandis que la deuxieme etait menee aux ecartements rectangulaires. Les techniques d'analyse des composants de rendement (YCA) etaitent utilisees pour etudier le rendement et la reaction des composants de rendement en fonction de niveaux differents de la densitede la population des plantes. Les resultats ont demontre que la variation en rendement des graines m-2 parmi les densites de la population des plantes etait associee aux reactions de quelques composants reproductifs de rendement e.g. le rapport masse des graines (KDM/Nk) - densite de la population des plantes. Par contre, les reactions des composants vegetatifs ces densites-la avaient des effets minimes en rapport avec les differences en rendement des graines dans leur ensemble. On peut conclure que la technique de la division a double dimension (TDP) de la technique de (YCA) pourvoit une methode efficace pour identifier des determinants physiologiques et morphologiques de la variation de rendement d'arachide en conditions de champ. De ces resultats, on peut deduire que la variation dans la production des matieres seches des graines etait liee la reaction des traitements de KDM/NK, Npg/A1; NPG, NK/NP et NB/N. Mots Clés Arachis hypogaea L., matires seches des graines, densite de la population des plantes, division a double dimension, composants de rendement

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