D. Karamura, W. Ocimati and E. Karamura BIOVERSITY

Assessment of possible climate change (temperature) effects on AAA EAH beer bananas

Introduction (Bananas in East Africa)

• A secondary centre of banana diversity with 80-120 clones grown on-farm

• Major staple but also sold in local markets for cash income

• About 20 million tonnes are produced and consumed by the region annually

• Annual percapita consumption is up to 600 kg. one of the highest globally

• Occupies 30-40 % of land under crops

• A host of threats to banana diversity since the last 20 years

New threats to bananas as a combination of biotic and a biotic stresses.

1. The unpredictability of seasons where farmers often lose their crops due to unexpected drought and floods.

2. The highland bananas are particularly threatened because the highland agro-ecologies are rapidly shrinking in the face of climate change:a. the ecological ranges of most pests and diseases have been extended-black sigatoka was originally a disease in low lands (, 1200 masl) but increasingly it is observed around 1400 masl in highland banana systems.b. In the western rift valley, banana bunchy top disease (BBTD) for more than 50 years has been confined to the Ruzizi Valley in Burundi. Recent surveys have revealed that the disease has climbed out of the valley into the surrounding highlands in Rwanda and DRCongo.

AAA-EAH Beer bananas

• Considered mutants of the green-cooking genotypes .

• The fruits are bitter and astringent due to the higher tannin content than the green-cooking types.

• Have plenty of very sticky, fast flowing milky latex.

• Have heavily pigmented stems and upper sheaths.

• Use of beer bananas for cooking gives food which is unpalatable due to its lumpy texture, poor colour as well as an astringent flavour. Hence used for beer.

Observations on the distribution of beer bananas in east Africa

• A higher proportion of beer clones in east Africa are grown above 1500 than below 1200 masl.

– In the Pare Mountains, the Ilalyi (AAA-beer bananas) grow between 1600-2500 masl,

– In the Uluguru mountains whose height goes above 2,500masl the Kitombo and Luholele (AAA-beer bananas) are the dominant cultivars.

– In Rwanda, 69% of Musa grown is AAA-beer banana, occupying altitudinal zones above 1600 meters.

• The possible role of cool temperatures in the reversion from green-cooking to beer remains unclear.

What is the role of altitude and (hence temperature) in the selection of mutations such as astringency?Although beer mutants have been observed in highland bananas for a long time their frequency of occurrence is still not well understood (De Langhe, 1964, Simmonds ,1966).What is the role of farmers in initiating and adjusting the numbers and proportions of cultivars in their fields?

Research questions

Methodology

• 24 Sites selected in major growing areas of Uganda, using GIS

• Sites grouped into 4 based on altitudinal zones.

• 5 farms randomly selected per site

• Determine cultivar proportions (beer visa-avis green cooking) across altitudinal zones

Site District Village Elevation

1 Kabale Bukinda 1760-1830 *

2 Bushenyi Mitooma 1510-1670 *

3 Bushenyi Ryeru 1340-1420 *

4 Mbarara Rukiri 1430-1460 *

5 Mbarara Bubare 1360-1410 *

6 Mbarara Rugaga 1430-1470 *

7 Kabarole Buhesi 1520-1560 *

8 Rakai Kagamba 1190-1330

9 Masaka Matete 1200-1270

10 Masaka Ntusi 1260-1290

11 Mpigi Kabulasokwe 1160-1200

12 Mpigi Buwama 1180-1260

13 Mubende Kitenga 1200-1215

14 Mubende Bulera 1250-1310

15 Mubende Madudu 1210-1280

16 Kibale Nkoko 1080-1180

17 Kibale Matale 1180-1240

18 Kiboga Bukomero 1160-1200

19 Luwero Nyimbwa 1230-1280

20 Luwero Butuntumula 1130-1180

21 Mukono Kayunga 1050-1070

22 Iganga Bulongo 1070-1120

23 Mbale Butiru 1250-1270

24 Kapchorwa Kaseren 1820-1870 *

Study sites

No.

Beer genotype Progenitor AAA-green cooking

Presence of either progenitor or mutant at given site

Presence of both mutant and progenitor at given site

1 Entukura Enzirabahima 4, 5 , 6 13 only cooking 1,2,3,5,7

2 Enshika Enshenyi 4,5,6, 24

3 Entundu Entundu 1,3,4,5,6,9,10,19,22

4 Enkara Nakayonga, 2,3, 4,5,6,7 12 only cooking

5 Engumba, Ingumba Mukazimugumba 5,6 ,9

6 Enyarukira Nalukira, 3,4,5,6,7,8, 9, 10, 11 7

7 Enywamaizi Nambi, 4, 5, 6,7, 8, 10, 11 13, 15, 16 , 17, 18, 19, 20,21 14 only cooking

9, 10,23

8 Kyamalindi Kafunze 5,6,8, 10

9 Mburiondet Beer Mburiondet 4,24

10 Konjowet Beer Konjowet 24

11 Oruhuuna Luwuna 4

12 Nalwezinga Nalwezinga 8

13 Musenzealanda Musenzealanda 19,20

14 Ensowe 8,9,10,11,12, 19,

15 Entatemwabagyenyi

1,2,4

16 Engote 1,3

17 Enyanzya 4

18 Mende 20

19 Bagandeseza 19,20

20 Nakanyala 8

21 Balekagabo 7

22 Endirira 2,4

23 Endembezi 2,4

Beer cultivars found in the 24 sites

Altitudinal Ranges (masl)

No. sites

Proportion of beer cultivars

1000-1200 4 0.25

1201-1400 9 3.67

1401-1600 4 7.75

1601-1800 2 9.51

Proportion of beer cultivars across altitudinal ranges

How will the varying and unpredictable climatic changes affect the distribution and proportions of cultivars/ landraces on farm?

What would be the implications to the livelihoods of poor communities that depend on land race diversity ?

Considerations

Thank you for your attention