Cassava

Varieties

Cassava Varieties

 

1. INTRODUCTION

Cassava growing in Rwanda was first introduced in Rwanda in 1930 by Belgians. Cassava   is a staple food crop ranking third in country after sweet potatoes and bananas in terms of importance. The production of cassava has drastically declined in the last decade due to mainly diseases, pests and lack of disease resistant varieties.

The cassava plant is grown for its roots which are used as food. Cassava has the ability to grow on poor soils where other crops do not grow well. Cassava is also a suitable crop to grow when there is drought. Because cassava roots can be stored in the ground for up to 24 months, and some varieties for up to 36 months, harvest may be delayed until market, processing, or other conditions are favorable.

The cassava plant is used mainly for food for human consumption. It can also be used as animal food. In many homes cassava provides a source of food and supplies energy. It can be made into flour for porridge of Ugali or roasted or boiled. Cassava leaves are also consumed as a green vegetable, which provides protein and vitamins A and B.

2. VARIETIES

Normally, there are two types of Cassava varieties: bitter and sweet cassava varieties.

Cassava is referred to as “sweet” it is less poisonous. Cassava contains large quantities of cyanide compounds, which must be processed out of the tubers before they can be safely eaten. The sweet variety of cassava has fewer of these compounds, and does not require as much processing. Bitter cassava is very similar in cultivation and general appearance to sweet cassava, but produces much higher quantities of cyanide compounds. Sweet cassava my contain as few as 40 parts per million, while bitter cassava varieties can range as high as 490 parts per million. Any quantity of cyanogens over 50 parts per million is considered to be hazardous. The presence of cyanide in cassava constitutes a clear threat to health, unless these compounds are removed before the cassava is consumed. Unprocessed cassava is toxic enough to cause death, but insufficiently processed cassava will also cause mortality over a period of time, especially when quality protein is absent from the local diet. There are several methods of removing the cyanide from cassava. Simple drying reduces the level of cyanide, though this may not be adequate to make it safe for consumption. Soaking the roots in water first, to leach out cyanide, produces a safer starch. So does fermenting the roots, either whole, shredded or in pieces, before drying. Roasting the tubers, or boiling them in multiple changes of water, will also reduce the cyanide content to manageable levels.

In Rwanda, we have a number of cassava varieties which are suffering from various diseases and pests.

Those varieties are described in the table below:

  Crop: Cassava ( Manihot esculentum Crantz)

Name

Code

Released

AEZ

Taste

Cycle (month)

Yield

(t/ha)

Other Important Traits

Gitamisi

Eala 07

1975

LA, MA

 

Bitter

18 – 24

40

Susceptible to CMD and Green mite, Dark brown stem, greenish red petiole, dark green leaves, dark brown external root color and white root pulp

Rutanihisha

Creolinha

1985

LA, MA

 

Bitter

15 – 18

40 - 45

Susceptible to CMD and Green mite, silver stem color, greenish red petiole, dark green leaves, cream external root color and white root pulp

Gacyacyali

Local

1985

 MA

 

Sweet

12 – 15

25

Susceptible to CMD and Green mite, silver stem color, purple petiole, dark green leaves, dark brown external root color and white root pulp

Gahene

Local

1988

LA, MA

 

Bitter

12 – 15

30

Susceptible to CMD and Green mite, silver stem color, purple petiole, purple green leaves, cream external root color and white root pulp

Bukalasa

Local

1985

LA, MA

 

Intermediate

12 – 15

25

Susceptible to CMD and Green mite, silver stem color, greenish red petiole, dark green leaves, light brown external root color and white root pulp

Iminayiro

Local

1985

LA, MA

 

Intermediate

12 – 15

20

Susceptible to CMD and Green mite, dark brown stem color, yellowish green petiole, dark green leaves, light brown external root color and white root pulp

Mavuta

Local

1988

LA, MA

 

Intermediate

12 – 15

20

Susceptible to CMD and Green mite, silver stem color, purple petiole, dark green leaves, light brown external root color and cream root pulp

Nyirakarasi

Local

1986

LA, MA

 

Bitter

12 – 15

25

Susceptible to CMD and Green mite, golden stem color, purple petiole, purple green leaves, cream external root color and white root pulp

Kiryumukwe

Local

1985

LA

 

Sweet

10 – 15

25

Susceptible to CMD and Green mite, silver stem color, yellowish green petiole, dark green leaves, light brown external root color and white root pulp

Maguruyinkware

Local

1985

LA, MA

Intermediate

12 - 15

20 -25

Susceptible to CMD and Green mite, grey stem color, greenish red petiole, dark green leaves, dark brown external root color and white root pulp

Nyiramabuye

Local

1985

LA

 

Intermediate

15

35

Susceptible to CMD and Green mite, green yellowish stem color, greenish red petiole, dark green leaves, dark brown external root color and white root pulp

Imisurupiyo

Local

 

1985

LA, MA

 

Intermediate

15

20

Susceptible to CMD and Green mite, green yellowish stem color, red petiole, light green leaves, light brown external root color and white root pulp

Ndamirabana

TME 14

2006

LA, MA

Sweet

10 - 12

40

CMD resistant, Tolerance to green mite, silver stem color, purple petiole, light green leaves, cream external root color and white root pulp

Cyizere

I92/0057

2006

LA, MA

Intermediate

15

40 - 45

CMD resistant, Tolerance to green mite, green yellowish stem color, yellowish green petiole, light green leaves, dark brown external root color and white root pulp

Mbakunga

haze

95/NA/00063

2006

LA, MA

Bitter

12

45

CMD tolerant, Tolerance to green mite, silver stem color, purple petiole, light green leaves, white external root color and white root pulp

Mbagaru

mbise

MH95/0414

2006

LA, MA

Intermediate

12 – 15

30 – 35

CMD tolerant, Tolerance to green mite, golden stem color, purple petiole, light green leaves, light brown external root color and white root pulp

Rwizihiza

MM96/3920

2009

LA, MA

Sweet

12

30 - 35

CMD resistant, Tolerance to green mite, silver stem color, purple petiole, light green leaves, light brown external root color and white root pulp

Seruruseke

MM96/5280

2009

LA, MA

Sweet

12

25 - 30

CMD resistant, Tolerance to green mite, silver stem color, purple petiole, light green leaves, dark brown external root color and white root pulp

Mavoka

MM96/0287

2009

LA, MA

Sweet

10-12

35 -40

CMD resistant, Tolerance to green mite, grey stem color, greenish red petiole, dark green leaves, dark brown external root color and yellow root pulp

Garukunsubire

MM96/7204

2009

LA, MA

Sweet

12

30 - 35

CMD resistant, Tolerance to green mite, sylver stem color, greenish red petiole, dark green leaves, dark brown external root color and yellow root pulp

AEZ = Agro Ecological Zone, LA = Low Altitude, MA = Middle Altitude