Browsing by Author "Uwimana, Brigitte"

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    Evaluation of banana germplasm and genetic analysis of an F1 population for resistance to Fusarium oxysporum f. sp. cubense race 1
    (Euphytica, 2019) Kabiita Arinaitwe, Ivan; Teo, Chee How; Kayat, Fatimah; Tumuhimbise, Robooni; Uwimana, Brigitte; Kubiriba, Jerome; Swennen, Rony; Ann, Jennifer; Rofina Yasmin Othman, Harikrishna
    Fusarium wilt of bananas (Musa spp.), caused by Fusarium oxysporum f. sp. cubense (Foc) causes up to 100% yield loss in bananas. Foc race 1 in particular is very devastating to dessert bananas in Uganda. One of the effective control strategies for the disease is the development of resistant cultivars through breeding. The objectives of this study were to identify suitable banana germplasm for generating a segregating population for resistance to Foc race 1 and understand the mode of inheritance of resistance to Foc race 1. Twenty-two banana accessions sourced from the National Agricultural Research Organisation in Uganda were challenged with Foc race 1 in a screen house experiment. Monyet, resistant to Foc race 1 and Kokopo, susceptible, were selected and crossed to generate 142 F1 genotypes. These F1 genotypes were also challenged with Foc race 1 in a screen house experiment. Data were collected on rhizome discoloration index (RDI), leaf symptom index (LSI) and pseudo-stem splitting (PSS), and analysed for variability. The banana accessions evaluated showed varying degrees of resistance to Foc race 1. Segregation ratios for resistant versus susceptible progenies fitted 13:3 (v2 = 0.12, P = 0.73) for RDI and 11:5 (v2 = 3.04, P = 0.08) for PSS. Estimated broad sense heritability was 27.8% for RDI, 13.9% for LSI and 14.7% for PSS. The results suggest that resistance to Foc race 1 in banana is controlled by at least two dominant genes with epistatic interaction and that
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    Molecular Markers and Their Application in Fusarium Wilt Studies in Musa spp.
    (Sains Malaysiana, 2019) Kabiita Arinaitwe, Ivan; Teo, Chee How; Kayat, Fatimah; Tumuhimbise, Robooni; Uwimana, Brigitte; Kubiriba, Jerome; Harikrishna, Jennifer Ann; Othman, Yasmin
    Bananas and plantains (Musa spp.) are an important socio-economic fruit crop grown worldwide. Their production across the regions where they are grown is largely hampered by pests and diseases. Fusarium wilt is a disastrous diseases of bananas caused by the fungal pathogen Fusarium oxysporum f.sp. cubense (Foc). Managing it with chemicals, biological control agents and cultural methods is ineffective. Host plant resistance is the most effective and durable approach of managing most pest and disease epidemics in most plant species and could equally be effective in managing Fusarium wilt in bananas. Crossbreeding as one of the ways to introgress disease resistance genes and phenotyping for biotic and abiotic stresses currently used in banana breeding is apparently difficult to apply because of banana’s low fertility, gigantic size, and long-life cycle which prolongs its breeding cycle. There is, therefore, a need to apply molecular markers in banana genetic improvement for Fusarium wilt resistance because of their accuracy, speed, robustness and effectiveness of operation. The objective of this article was to review and discuss molecular markers that have been successfully used in studying Fusarium wilt in bananas and some other important crops. Molecular markers discussed in this article include Random Amplified Polymorphic DNA, Sequence Characterized Amplified Region, Simple Sequence Repeat, Inter-Simple Sequence Repeat, and Single Nucleotide Polymorphism. The information discussed in this article informs future decisions to identify suitable marker systems for fine mapping of target regions and accelerated identification of quantitative trait loci for Foc resistance in bananas.
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    Use of timelapse photography to determine flower opening time and pattern in banana (Musa spp.) for efficient hand pollination
    (Scientific Reports, 2021) Waniale, Allan; Swennen, Rony; Mukasa, Settumba B.; Tugume, Arthur K.; Kubiriba, Jerome; Tushemereirwe, Wilberforce K.; Uwimana, Brigitte; Gram, Gil; Amah, Delphine; Tumuhimbise, Robooni
    Sterility and low seed set in bananas is the main challenge to their conventional genetic improvement. The first step to seed set in a banana breeding program depends on pollination at the right time to ensure effective fertilization. This study aimed at determining bract opening time (BOT) to enhance efficient pollination and seed set in bananas. A Nikon D810 digital camera was set-up to take pictures of growing banana inflorescences at five-minute intervals and time-lapse movies were developed at a speed of 30 frames per second to allow real-time monitoring of BOT. Genotypes studied included wild banana (1), Mchare (2), Matooke (4), Matooke hybrid (1), and plantain (1). Events of bract opening initiated by bract lift for female flowers (P < 0.01) started at 16:32 h and at 18:54 h for male flowers. Start of bract rolling was at 18:51 h among female flowers (P < 0.001) and 20:48 h for male flowers. Bracts ended rolling at 02:33 h and 01:16 h for female and flowers respectively (P < 0.05). Total time of bract opening (from lift to end of rolling) for female flowers was significantly longer than that of male flowers (P < 0.001). On average, the number of bracts subtending female flowers opening increased from one on the first day, to between one and four on the fourth day. The number regressed to one bract on day eight before start of opening of bracts subtending male flowers. There was a longer opening interval between bracts subtending female and male flowers constituting spatial and temporal separation. Bract rolling increased from partial to complete rolling from proximal to the distal end of the inflorescence among female flower. On the other hand, bracts subtending male flowers completely rolled. Differences in BOT of genotypes with the same reference time of assessment may be partly responsible for variable fertility. Hand pollination time between 07:00 and 10:00 h is slightly late thus an early feasible time should be tried.