DETERMINANTS OF RESOURCE ALLOCATION IN LOW INPUT AGRICULTURE: THE CASE OF BANANA PRODUCTION IN UGANDA

Replaced with revised version of paper 09/01/04.Crop Production/Industries,

First report of banana bunchy top disease caused by Banana bunchy top virus in Uganda

Banana bunchy top virus (BBTV) that causes banana bunchy top disease (BBTD) is ranked among the top 100 invasive species in the world. Despite being omnipresent in the Democratic Republic of Congo (DR Congo) and South-Western Rwanda for over 2 decades, BBTV had not been reported in neighbouring Uganda. However, in 2020, banana plants with BBTD characteristic symptoms were observed in Arua City located in the North Western part of Uganda, bordering DR Congo. BBTV in these plants was confirmed using PCR and the comparison of the genomic DNA nucleotide sequence with nucleotide sequences in NCBI data base (https://www.ncbi.nlm.nih.gov/). The gDNA nucleotide sequence had 98-99% similarity with BBTV isolates form different countries in Africa, Asia, South Pacific and the USA. These results constitute the first confirmation of BBTD in Uganda. This infection is anticipated to have been introduced from DR Congo, mainly through infected planting materials. Once established, BBTD is very difficult to control on small-scale farms. It is therefore crucial to urgently understand the current spread of the virus, determine its risk to banana production in Uganda and devise proactive measures for its management

'NABIO808' (Syn. 'NAROBAN5'): A tasty cooking banana cultivar with resistance to pests and diseases

Abstract 'NABIO808' is a newly released, conventionally-bred triploid cooking banana cultivar in Uganda. It produces an average bunch yield of 54.5 t ha-1 yr-1 and is resistant to weevils, nematodes, and black Sigatoka. Additionally, its food is yellow, soft, and tasty, like that of most preferred landrace cultivars, making it more acceptable to end-users

An economic assessment of banana genetic improvement and innovation in the Lake Victoria Region of Uganda and Tanzania

This research report highlights the findings from a set of studies undertaken by the International Food Policy Research Institute, along with several national and international research institutions, to assess the economic impact of improved cultivars and management practices on smallholder farmers in the Lake Victoria Region of Uganda and Tanzania— an area where the cooking banana is both economically and culturally important. Genetic transformation is a promising alternative for improving the resistance of banana plants to the pests and diseases that cause serious economic losses, because bananas, unlike rice, wheat, and maize, are difficult to improve through conventional breeding techniques. The team of researchers posed three broad questions: What is the current level of adoption of improved cultivars and management practices, given the constraints to banana production and marketing? What are the prospects that banana growers will adopt cultivars with transgenic resistance to pests and diseases, given existing constraints? What is the potential impact on the banana industry of a range of genetic technologies now under development by national researchers? Findings confirm that smallholder farmers value the crop traits targeted for introduction by current bioengineering efforts, and that transgenic bananas have the potential to benefit the poor. The focal role of farmers in developing and promoting planting material systems and the influence of social capital on technology adoption are both demonstrated by the baseline data, with implications for the design of extension systems. The research summarized in this report is new in several respects. First, it documents the uptake of newly released banana hybrids and other recommended banana practices on semisubsistence smallholder farms in East Africa. Second, a complete taxonomy of distinct banana cultivars grown in the region has been developed. Third, the research puts existing knowledge into perspective with advanced social science methods. The findings and recommendations resulting from this study will be useful for policy decisions in the region, contributing initially to technological development and dissemination, and ultimately to increased crop productivity

Isolation and characterisation of a banana CYCD2;1 gene and its over-expression enhances root growth

Stimulation of the cell cycle by over-expression of Arabidopsis CyclinD2;1 enhanced growth in tobacco and rice, but not Arabidopsis. To broaden the range of species and to improve an important crop species for developing countries, a CyclinD2;1 homologue was isolated from an East African highland banana cultivar ‘Nakasabira’ (Musa spp., AAA group) and designated Musac;CYCD2;1 (Genebank accession no HQ839770). Musac;CYCD2;1 amino-acid sequence exhibited 40, 54, 57 and 57% identity with CYCD2;1 sequences of Arabidopsis, rice, maize and wheat, respectively. Over-expression of Musac;CYCD2;1 driven by the CaMV 35S promoter in cultivar ‘Sukali ndizi’ (AAB) resulted in transformed plants with no significant increase in total banana CYCD2;1 transcripts in the shoot, but up to 66-fold increase of total banana CYCD2;1 transcripts in roots. Correspondingly, transformed plants had no change in above-ground growth but produced longer main roots and more lateral roots under in vitro conditions. A deeper root system was observed in one transgenic line relative to non-transformed plants when grown in soil. Results demonstrate that a banana homologue of Arabidopsis CYCD2;1 can also enhance growth in a homologous background and the potential of enhancing banana root growth.Key words: CyclinD2;1 gene, Musa spp., banana transformation, CyclinD2;1 over-expression, root growth

Variation among banana weevil Cosmopolites sordidus (Germar) populations in Uganda as revealed by AFLP markers and corm damage differences

Abstract Background The banana weevil Cosmopolites sordidus (Germar) is a major production constraint of bananas and plantains (Musa spp.) in the world. Differences in damage levels and pesticide response across regions led to the postulation that there might be considerable variation between banana weevil populations (biotypes) with varying levels of virulence. One of the most sustainable options for banana weevil control is the use of host plant resistance. While new resistant varieties are being developed through both conventional crossbreeding and biotechnology, there is a need to assess the genetic variation of banana weevil populations from eastern, central, southern, southwestern and midwest regions of Uganda to determine whether there are biotypes with different virulence levels. This would help guide new control strategies to target all the possible biotypes. The amplified fragment length polymorphism (AFLP) technique was used to analyze population genetic diversity using four primer combinations (EcoRI/MSeI). Results Analysis of molecular variance results presented no evidence to support significant genetic variability among the banana weevil populations from eastern, central, southern, southwestern and midwest regions. Practically, all the genetic variation was found to reside within populations (97% for sites and 98% for regions), with only approximately 3% and 2% residing among populations of sites and regions, respectively. Conclusions and recommendations AFLP markers clustered the banana weevils into two distinct populations consequently supporting the hypothesis of possible presence of banana weevil biotypes in Uganda. However, attempts should be made to make follow-up studies on the seemingly unique population of eastern Uganda using more robust molecular techniques to establish whether the eastern Uganda population constitutes a different biotype

Changing Dynamics in the Spread and Management of Banana Xanthomonas Wilt Disease in Uganda Over Two Decades

Banana Xanthomonas wilt (BXW) is a destructive disease caused by Xanthomonas vasicola pv. musacearum (Xvm), a bacterium that indiscriminately infects all banana varieties grown in East and Central Africa (ECA). In this region, BXW was first reported in 2001 in Uganda and was projected to eliminate >90% of Uganda's banana crops (worth USD4 billion) if not controlled in less than 10 years. Lack of basic information led to application of control approaches that were based on similarity of BXW symptoms to those of Moko disease of banana. However, the approaches were unsuccessful and, in 7 to 9 years, BXW had covered six countries and threatened to wipe out the banana industry in ECA. However, BXW has been tamed to date, mainly due to relentless and systematic deployment of carefully crafted and packaged cultural control practices based on epidemiological information generated within target banana cropping ecosystems. In Uganda, the initial “top-down” communication approaches reached >85% of banana farming communities but did not mobilize the communities enough into action; hence, only 30% impact in controlling BXW was registered. In contrast, participatory approaches mobilized farming communities into action and effectively controlled BXW at field and community levels to near eradication. The approaches effectively controlled BXW in Uganda and, consequently, in eastern Kenya, northern Tanzania, Rwanda, Burundi, and the Democratic Republic of Congo. This article reviews step-wise processes leading to success over the 2 decades and identifies critical research gaps. Deployment of resistant genotypes is urgently needed as a significant addition to the BXW management toolbox to create BXW-free banana cropping systems in ECA. [Graphic: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license

Early Withering of Enlarged Ovules in Pollinated Fruits of Bananas (<i>Musa</i> spp.) Suggest Abortion after Fertilization

Sterility in edible bananas is as a result of a long history of anthropogenic-driven selection for sterile genotypes, since seed is not desirable in fruit pulp for human consumption. However, this poses a challenge to conventional genetic improvement by slowing breeding pipelines. In this study, we investigated whether pollen tubes reach all parts of the ovary, the position of fertilized ovule development in fruits, and potential seed set in selected banana genotypes. We selected four cultivars of East African Highland Cooking bananas (EAHBs), a Matooke hybrid ‘222K-1’, improved diploid ‘2905’, and wild bananas ‘Zebrina (G.F.)’ and ‘Calcutta 4’. There was evidence of pollen tubes in the distal, mid and proximal sections of the fruit, irrespective of hand position and genotype. Fertilization, as indicated by an increase in ovule size, happened along the entire length of the fruit but complete development was biased at the distal end in some genotypes. There were some differences in ovule fertilization rates between hands, with distal hands having more ovules and higher ovule fertilization rates. Ovule fertilization happens in bananas but the vast majority aborts, especially at the proximal end of the ovary. Ovule fertilization rates are generally much lower than available ovules