title: Diallel analysis of provitamin A carotenoid and dry matter content in cassava (Manihot esculentaCrantz).
abstract: Global efforts are underway to biofortify cassava (Manihot esculentaCrantz) with provitamin A carotenoids to help combat dietary vitamin A deficiency afflicting the health of more than 500 million resource-poor people in Sub-Saharan Africa. To further the biofortification initiative in Uganda, a 6×6 diallel analysis was conducted to estimate combining ability of six provitamin A clones and gene actions controlling total carotenoid content (TCC), dry matter content (DMC) in cassava roots and other relevant traits. Fifteen F1families generated from the diallel crosses were evaluated in two environments using a randomized complete block design. General combining ability (GCA) effects were significant for TCC and DMC, suggesting the relative importance of additive gene effects in controlling these traits in cassava. On the other hand, non-additive effects were predominant for root and shoot weight. MH02-073HS, with the highest level of TCC, was the best general combiner for TCC while NASE 3, a popular white-fleshed variety grown by farmers in Uganda, was the best general combiner for DMC. Such progenitors with superior GCA effects could form the genetic source for future programs targeting cassava breeding for TCC and DMC. A negative correlation was observed between TCC and DMC, which will require breeding strategies to combine both traits for increased adoption of provitamin A cassava varieties.
authors: National Crops Resources Research Institute, 9 km Gayaza-Zirobwe Road, P.O. Box 7084, Kampala, Uganda; Department of Plant Sciences, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa.
authors: Williams
authors: W
authors: Esuma
authors: National Crops Resources Research Institute , 9 km Gayaza-Zirobwe Road, P.O. Box 7084, Kampala , Uganda.
authors: Robert S
authors: RS
authors: Kawuki
authors: Department of Plant Sciences, University of the Free State , P.O. Box 339, Bloemfontein 9300 , South Africa.
authors: Liezel
authors: L
authors: Herselman
authors: Department of Plant Sciences, University of the Free State , P.O. Box 339, Bloemfontein 9300 , South Africa.
authors: Maryke Tine
authors: MT
authors: Labuschagne
keywords: biofortification; cassava; combining ability; genetic improvement; provitamin A carotenoid