Browsing by Author "Ibanda, Angele Pembele"

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    Genetics of Resistance in F2 Soybean Populations for Adzuki Bean Bruchid (Callosobruchus chinensis)
    (J Agric Sci, 2018-11-15) Msiska, Ulemu Mercy; Miesho, Belay Weldekidan; Tukamuhabwa, Phinehas; Kyamanywa, Samuel; Odong, Thomas Lapaka; Ibanda, Angele Pembele; Rubaihayo, Patrick
    Adzuki bean bruchid (Callosobruchus chinensis) is a significant pest of soybean in Uganda. To sustainably manage this pest, utilization of resistant soybean varieties is the key solution. Development of resistant varieties needs knowledge on modes of inheritance which is crucial in selection of parent materials. To identify parents, a study was initiated to determine the gene action and mode of inheritance of resistance to bruchids in soybean. Nine parental lines were crossed in a full-diallel at Makerere University Agricultural Institute, Uganda. The generated F1s were advanced to F2 and seeds were evaluated for response to bruchid infestation in a randomised complete block design. Ten seeds were infested with 10 randomly selected unsexed 1-3 day old bruchids. Genotypes showed significant differences in seed weight loss (swl), adult bruchid emergence (ABE) and Dobie susceptibility index (DSI) indicating that these parameters could be used to screen genotypes in genetic analysis. Mean squares of general combining ability (GCA) were significant (P < 0.05) for swl, DSI and number of ABE from the F2 seeds indicating additive gene action. Susceptibility parameters ABE and DSI showed significant specific combining ability (SCA) indicating non-additive gene action. Resistance was influenced by maternal effects indicating that direction of the cross was important. Genotypes S-Line 9.2 and S-Line 13.2A showed negative significant GCA effects for at least two of the susceptibility parameters indicating that they were the best parents for bruchid resistance breeding. The study established that additive, non additive and maternal effects governed the gene expression in soybean resistance to bruchids.
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    Relationship between 2-acetyl-1-pyrroline and aroma in Uganda rice populations with Oryza (barthi, glaberrima and sativa) backgrounds
    (African Journal of Biotechnology, 2019-11-30) Ocan, David; Odoch, Martin; Ibanda, Angele Pembele; Nuwamanya, Ephraim; Rubaihayo, Patrick Rutimbanzigu
    The sweet popcorn aroma conferred by 2-acetyl-1-pyrroline (2AP) is a highly economic trait of rice grain attracting premium price worldwide. This research study was conducted to determine the levels of 2AP in Ugandan rice lines with the aim of establishing a better understanding on the level and classes of 2AP and aroma phenotype. Concentration of 2AP was assayed using two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF-MS) in tandem with sensory evaluation. Substantial variations in aroma intensity within and between the Uganda rice families were recorded. However, the levels of aroma variation were strongly influenced by the type of rice, and the breeding population it was derived from. Hence, three aroma based categories, namely, nonaromatic, moderately aromatic and highly aromatic were identified. GC with complementary sensory evaluation suggested a highly complex nature of rice aroma, as several rice lines were re-classified on the basis of this study. The 2AP contents and aroma intensity for genotypes with O. glaberrima were low compared to O. sativa and O. barthi. Genotypes of Supa 5, Supa 1052, Yasmin aromatic and MET 3 contained high 2AP levels whereas MET 16, MET 6, AGRA 78, AGRA 55, AGRA 41 and Sande TXD 306 exhibited moderate 2AP contents. Therefore, in developing an optimal breeding strategy aimed at improving the aroma in rice, quantitative information about 2AP and complementary sensory evaluation are a prerequisite.