Agronomic and post-harvest characterization of three quality protein maize (QPM) hybrids developed in Ghana

Three 3-way quality protein maize (QPM) hybrid varieties, GHII0-5, GH132-28 and GH2328-88, developed in Ghana were the most productive among several varieties tested between 1994 and 1996 within Ghana and elsewhere in Africa, South America, and East Asia. Yield potentials of the three hybrids ranged from 6.3 to 7.3 t ha-I, representing 19 to 38 per cent yield advantage over the leading open-pollinated variety, Obatanpa. These were subsequently released in 1997 with the common names, Mamaba. Dadaba and CfDA-ba. respectively. To satisfY the requirement of the Ghana National Varietal Release Committee tor their release, and also guide seed growers and germplasm conservators, among others, in their operations, the hybrids were characterized by their agronomic traits, seed characters, and reaction to common t'oliar diseases. Among the agronomic traits, days to silking, tassel number, tassel arrangement, plant and ear heights, 'husk cover tightness, and leaf angleowere the most useful characters in distinguishing among tile three hybrids. The hybrid, GH110-5 (Mamaba), had the least number and the most compactly arranged tassels, and was also the shortest in plant height and ear placement. For the post-harvest characters, GH II 0-5 had the highest number of rows per cob, followed by GH132-28 (Dadaba) and GH2328-88 (CIDA-ba) in that order. Cob length and 1000-seed weight were highest in Dadaba (which was a mixture of flint and dent seeds), followed by Mamaba (flint) and CfDA-ba (dent). The long cobs, high number of rows, flinty nature, and high 1000-seed weight of Mamaba and Dadaba which possibly contributed to their high-yielding potential, are traits that plant breeders should be looking for when developing high-yielding crop varieties. All the hybrids showed high to moderate tole,rance to -common foliar diseases such as the maize streak virus disease, rust (Puccinia po/ysora), and Bipolaris maydis. The implications of these and other differences RESUME ~IEOU, E. A., $ALLAH, P. Y. K., TWUMASI-NRlYIE, S., OBENGANTWI, K., AHENKORA, K. & AOUSEI-AKOWUAH, P Caracterisation agronomique et de poste-reco/te de trois hybrides de mais qua/itatif riche en proteines (MQP) dlve/oppes au Ghana. Trois varietes des hybrides de mars qualitatif riche en proteines (MQP) a 3caracteres, GHIIO-5, GH132-28 et GH2328-88 developpees au Ghana etaient decouvertes d'etre les plus productifs parmi plusieurs varietes mises a I'essai entre 1994-1996, au Ghana et ailleurs en Afrique, Amerique du sud et Asie orientale. Les potentiels de rendement de trois hybrides variaient de 6.3 a 7.3 t ha-I, representant 19 a 38 pour cent d'avantage de rendement,sur la variete precedente de pollinisation libre, Obatanpa. Ceux-ci ttaient sorties par la suite en 1997 avec les noms communs respectifs de Malflaba. Dadaba, et CfDA ba. Aftn de satisfaire I'exigence de la Commite Nationale Ghaneenne de la Sortie de Varitte, pour les sortir et pour guider les produeteurs de graine et les gardiens de germeplasme parmi d'autres, dans leurs operations, les hybrides etaient caracterises bases sur leur traits agronomiques, les caraettres de graine et la reaction aux maladies foHaires communes. Parmi les traits agronomiques, jour a I'apparition de soies, nombre de gland, arrangement de gland, hauteur de plante et d'epi, etroitesse d'enveloppe de couverture et I'angle de feuille etaimt decouverts d'etTe les caracttres les plus utHes pour distinguer entre les trois hybrides .. L'hybride GHlIO-5 (Mamaba) avait Ie moindre nombre de gland qui est arrange d'une falton Ie plus compacte et etait Ie plus, court en taille de plante et en placement d'epi. Pour les caraettres de poste recolte, GHlIO-5 avait Ie plus eleve nombre de rayons par epi, suivi par GHJ3;Z-28 (Dadf!ba) et GH 2328-88 (CIDA ba) .dans I'ordre logique. La longueur d' epi et Ie poids de 1000-graine etaient les plus elc;ves en Dadaba (qui etait un melange des graines de silex et d'entaille), stiivi par Mamaba (silex) et CfDA ba Accra: National Science & Technology Press Original scientific paper. Received 4 Jan 2000; revised 29 May 200