Publisher: Bachudo Science Co. Ltd

Use of Polycross Technique In The Development of Sweetpotato Hybrid Lines For Resource-Poor Farming Systems

S. O. Afuape, P. I. Okocha, E. C. Nwauzor, D.n. Njoku
KEYWORDS: Polycross technique, resource-poor systems, clonal evaluation


Polycross has been variously used to generate half-sib sweetpotato hybrid seeds. Nine sweetpotato genotypes were used in 2003 to establish 81 crossing blocks at the eastern farm of the National Root Crops research Institute, Umudike, Abia State, using the polycross method. Each crossing plot was 6m2 in size. The hybrid seeds produced were raised to seedlings in 2004 in a nursery. The seedlings that emerged were visually screened based on their resistance/tolerance to sweetpotato virus disease. 54genotypes (51 selected clones from the seedling evaluation and three check cultivars) were evaluated in 2005 for yield traits using augmented incomplete block design. The soil was a poor acid soil typical of the eastern Nigerian soils, and fertilizer was not added to simulate the peasant farmers· condition. Data colleded on hybrid seeds included number of seeds per genotype, mean seeds per capsule, and percent capsule-tilling ability. while data colleded on clonal evaluation trial were yield (kg/plant), number of progenies of each parent evaluated, percent progenies selected per parent, and percent parental contribμtion to total offspring selected. Fifteen promising clones out of the 51 evaluated were selected. The progeny, 2532.0P.1.13-03NRSP.2 recorded the highest yield (600g/plant). Tanzania contributed 40% and TIS 2532.0P.1.13 contributed 33.33% of the seleded promising progenies. This study has confirmed the fact tbat clones that can be productive in resource-poor farming systems can effedively be developed through the polycross method.

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