EFFECT OF DROUGHT/IRRIGATION ON PROXIMATE COMPOSITION AND CARBOHYDRATE CONTENT OF TWO ENSET [ENSETE VENTRICOSUM (WELW.) CHEESMAN] CLONES

Abstract

Enset [Ensete ventricosum (Welw.) Cheesman] is an important root crop serving as a
carbohydrate rich food source in Ethiopia. Perennial crops, like enset, are often exposed to recurrent dry
periods which could greatly affect their growth, physiology and yield. The effect of induced
drought/irrigation on the proximate composition and carbohydrate content of harvestable plant parts
(pseudostem and corm) of two field grown enset clones (Ameratye and Yesherakinkye) was investigated.
Proximate analysis showed that extended drought significantly (P £0.05) reduced crude protein, ash
content, potassium and phosphorus contents of enset pseudostem and corm of the two clones. On the
other hand, crude fibber content and calcium levels were significantly higher in droughted groups than
irrigated ones. There were no significant treatment effects on crude fat content and /or magnesium
levels. Moreover, drought resulted in a significant increase in the level of soluble sugars and a decline in
starch content of plant parts in both clones. Droughted plants accumulated 2–4 fold more soluble
sugars than irrigated groups while the latter group gained 14–23% more starch. There was no
significant difference between the two clones for the parameters considered. Low nutrient content of
droughted plants could be the result of reduced nutrient uptake and assimilation caused by low soil
water content and limited energy source (carbon skeleton). The observed increase in soluble sugars
could be an indication of osmotic adjustment mechanisms in droughted enset plants. On the other
hand, the decline in starch content could be due to reduced carbon assimilation and/or starch
degradation.