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dc.contributor.authorKawere, Brasio Kigongo
dc.date.accessioned2019-11-14T13:39:52Z
dc.date.available2019-11-14T13:39:52Z
dc.date.issued2019-11-14
dc.identifier.citationKawere, B.K. (2019). Evaluation of compatibility of selected sweetpotato cultivars and optimization of a sweetpotato seed scarification protocol for sufficient germination of progeny seeds. Makerere Universityen_US
dc.identifier.urihttp://hdl.handle.net/20.500.12281/7176
dc.description.abstractSweetpotato (Ipomoea batatas) plays indispensable food, feed and industrial roles in many countries. In Uganda, the crop’s average yield is very low. Virus infections have been noted as critical at limiting the crop’s production although some local varieties have been characterized to possess varying degrees of resistance to virus infections through reversion. Imported American cultivars, high in β-carotene but with barely any revertive potential, remain susceptible to viruses. Conventional hybridization, for the development of progenies that revert and also having high βcarotene containing roots is yet to be done. For effective introgression of genes, the involved parents have to be compatible. The compatibility between the reverting East African cultivars and the two non-reverting best American cultivars is not known. Seeds from compatible crosses often fail to germinate due to hard seed coat. This humpers success in breeding of sweetpotato. Many of the available scarification methods give low and non-uniform seed germination. In this study, incompatibility and crossability/compatibility relationships were determined in series of hybridization crosses between five parental (p) sweetpotato cultivars; two American (Beauregard (BQ) and Resisto (Rs) and three East African improved cultivars (NEW KAWOGO (NK), NASPOT 1 (N1) and NASPOT 11 (N11). Variability between the compatibility indices (CI; number of seeds per capsule) of the combinations was used to assess level of compatibility. For scarification, nine methods; two mechanicals, three- thermal (hot water), three chemical (sulfuric acid) and a control with water at room temperature were evaluated and assessed for their germination indices (GI). Variance analysis, revealed significant variability (P< .001) between the cross combinations evaluated for CI. Combination N1XNK had the highest C.I (3.65) that is, a 91.25 % capsule fill. Three reciprocal crosses of NKXN1, BQXNK and N1XNK were unsuccessful. Cultivars New Kawogo and NASPOT 11 appeared to be completely incompatible. The variability observed in the protocols evaluated for their GI was significant (P ≤ 0.05). Mechanical (GI =76.7%) and Sulfuric acid (GI=68.1%) scarification methods significantly improved germination of sweetpotato seeds in this study. The mechanical method of pin pricking induced the highest seed germination (78.9%) followed by sand papering (74.4%). Thermal scarification methods were unpredictable. These results imply that involvement of these parents in hybridizations according to the compatible combinations identified can effectively reduce the time and resources that could be wasted on incompatible crosses. Likely, employing mechanical and sulfuric acid scarification protocols will reduce the risk of genetic loss of improved progeniesen_US
dc.language.isoenen_US
dc.publisherMakerere Universityen_US
dc.subjectCompatibilityen_US
dc.subjectSweetpotatoen_US
dc.subjectCultivarsen_US
dc.subjectSeed scarification protocolen_US
dc.subjectGerminationen_US
dc.subjectProgeny seedsen_US
dc.titleEvaluation of compatibility of selected sweetpotato cultivars and optimization of a sweetpotato seed scarification protocol for sufficient germination of progeny seedsen_US
dc.typeThesisen_US


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