BREEDING

INTRODUCTION
Uganda is a country well-endowed with significant natural resources, including ample fertile land, regular rainfall, and mineral deposits. The economy is basically agricultural, and it occupies 80% of the working population.

Uganda’s moderate climate is especially pivotal to the production of both livestock and crops such as bananas. Different banana varieties that are hybrids with AAA, AAB and ABB genome constitu­tions are a staple food for a billion people in Asia and Africa and have 2n=3x=33 chromosomes.

The most widely grown cultivars are cooking types belonging to the East African highland banana (EAHB) subgroup (AAA genome).  The other bananas grown in the country include dessert bananas, such as 'Sukali Ndizi’  (ABB genome) and 'Bogoya’ (AAA genome), Plantain cultivars (locally called 'Gonja') (AAB genome) for roasting and 'Kayinja’  (ABB genome), and 'Kisubi'  (ABB genome) for making beer.

Background:
East African Highland bananas (commonly known as “matooke” in Uganda) are triploid banana cultivars originating from the African Great Lakes region. Bananas and plantains (Musa spp.) are a major staple food for more than 20 million smallholder farmers in Uganda. EAHB are also known as the Mutika/Lujugira subgroup.

The Biology of EAHBs (growth cycle) has 3 stages: Vegetative development (6-8 months), Flowering (3 months) and Fruit stage (3 months).  This means the time between planting a banana plant and the harvest of the banana bunch is from 9 to 15 months, depending on the variety grown and growing conditions. Banana fruits are seedless. Such fruits are called parthenocarpic, i.e., they produce fruit without fertilisation.

EAHB (Matooke) bunches are harvested at fruit mature green stage, peeled, wrapped in banana leaves, steamed or boiled, mashed, then can be eaten with or without a sauce.  The fruits may also be eaten directly after boiling or steaming. About 70% of matooke production is consumed at household level while 30% is sold through agents/brokers, wholesalers and retailers to the urban consumers as bunches, clusters or fingers. In Uganda, the annual domestic banana consumption is between 220-460 kg/person and is the highest in the world.

Banana and Plantation Production

Banana and plantain production information in most banana-growing countries in Africa between the year 2000 (FAOSTAT, 2000) and 2017 (FAOSTAT, 2017) (Arinaitwe et al. 2019). Although bananas have the estimated production potential of >70 tonne/ha/yr, from the recent 1990's, the production reduced to 10-15 tonnes/ha/year in Uganda. It's plantation life also reduced from about 30 yrs to 5 yrs. This declining productivity was because of the complex problems such as pests and diseases, reduced soil fertility, poor agronomy practices, inferior varieties, drought and socio-economic problems. All these led to the reduced yield ad short plantation life. Some of the common pests and diseases included; Nematodes, Weevils, Black Sigatoka, Fusarium wilt and the Banana bacterial wilt (BBW).

The image (below) is of the common pests and diseases that affect bananas in East Africa.

The EAHB crossbreeding programs by the National Agricultural Research Organization (NARO) were established in the mid-1990s in Uganda with aim to;

• Devise means to control pests and diseases
• Develop and release bananas similar to local varieties but with increased resistance to pests and diseases
• Develop farmer acceptable high yielding banana varieties

In matooke breeding, there are mainly four components; parent improvement, variety development, evaluation trials and data management.Below image is an illustration of the main components of banana breeding.

The Parent Improvement component involves selection and evaluation of improved parents for incorporation. The main objective is to develop quality parents with desirable traits absent in the local preferred varieties such as resistance to pests and diseases and tolerance to drought.

After, the genotypes that are generated from crosses are planted. This stage is called Early Evaluation Trials (EETs). All the genotypes which are planted in EET trials are different from each other and there is always a single copy of each genotype. Agronomic, yield, disease, indicative sensory data are collected from each genotype. All genotypes which show up good and promising traits are taken for sensory evaluation.

After the sensory evaluation, then the genotypes advance to Preliminary Yield Trials (PYTs). The main objective of this component is to evaluate and recommend quality and resistant matooke hybrids for advancement to advanced yield trials.

This involves accessing agronomic and yield performance of matooke hybrids, determining the resistance of matooke hybrids to black sigatoka, weevils and nematodes, accessing the indicative cooking qualities of matooke hybrids and selecting and delivering matooke hybrids bunches for sensory evaluation.

The Advanced Yield Trials component involves Distinct Variety Selection (DVS) data collection and Participatory Variety Selection (PVS) which also involves both sensory evaluation + yield evaluation. Below is pictorial on the activities under the advanced yield trials or on-farm trials ongoing in different regions in the country.

A number of improvements have been made in East African Highland Banana breeding between 1990 and 2020. The NARO Banana breeding team has bred and released seven banana (matooke) hybrids since 1990’s. These hybrids are high yielding coupled with resistances to common pests and diseases. They include:

• Pest and disease resistant
• Give higher yields
• They have improved crop quality / nutritional value
• Cycling, plant architecture, bunch orientation
• Shorter cropping cycle
• Improved taste
• Tolerant to harsh weather conditions i.e drought.