Parametres genetiques du manioc.
1984
Mahungu N.M. | Chheda H.R. | Fatokun C.A. | Hahn S.K.
We investigated six diverse cassava populations grown during 1979-80 and 1980-81 at the International Institute of Tropical Agriculture (IITA), Ibadan, to estimate genetic parameters for 22 traits of cassava. The data when analyzed, revealed that: considerable variation existed both within and between the populations for most of the characters; the coefficients of variation for phenotype and genotype were largest for root yield (85% and 62%, respectively), quite large for the roots per plant and root size (60% and 40%), moderate for harvest index and total number of branches (45% and 30%, respectively) and low (less than 30% and 15%) for stem girth, canopy width, and plant height at harvest. Heritability estimates as well as expected genetic gain also varied considerably. On average, root yield and number of roots showed moderately high heritability (50%) and high expected response to selection (88% and 64%, respectively). Relatively high heritability values were obtained for harvest index (49%) and dry matter content (52%), but they were associated with expected genetic gains of only 50% and 29%, respectively. Agronomic traits such as stem girth, canopy width and plant height at harvest showed moderate to low heritability values (32-42%) associated with low expected genetic advance (15-18%).
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