AGRONOMIC EVALUATION OF SOME ELITE CASSAVA GENOTYPES IN THE RAIN FOREST AGROECOLOGY OF SOUTHEASTERN NIGERIA

Cassava (Manihot esculentus) is a first-ranking carbohydrate staple in Nigeria and is very popular in the food systems of the humid and subhumid agroecological areas. It has high potential needs with diverse utilization capacities. Unfortunately, the current annual output of the crop is very low due to the predominant use of local clones which are disease-prone with characteristically low yield potential. Authentic information on yield capacity of the recently released CMD-resistant genotypes is still lacking. This formed the basis of the study. The design of the trial was a randomized complete block (RCB) involving fifteen clones (96/1565, 96/1642, 96/1089A, 96/2205, 94/0561, 95/0289, 02/0026, 04/0026, 95/0379, 92B/00061, 94/0039, 97/3200, 91/02324 and 95/0166) and three checks (4(2) 1425, 82/00058 and TME 30572) as treatments, each replication four times. The experiment was set at the Crop Production Farm of the University of Calabar in 2004 and 2005 main cropping seasons.  Cassava Mosaic Diseases (CMD) resistant clones were planted at 10,000 plants/ha in the first week of April each year and harvested after ten months of growth. Data collected were plant height (at harvest), total number and weight of marketable tubers/roots (weighing> 300g and > 20cm long), unmarketable tubers/roots (weighing < 300g and < 20cm long), per plot, foliage yield, and roots/tuber yield per hectare. Results obtained showed significant variations among the cultivars in all the parameters measured. Clones 96/1642, 96/0603 94/0561, 95/0289 and 92/0026 exhibited tall plant height like the check 82/0026, 97/3200 and 95/0166 produced high proportion of marketable tubers ranging from 45-75 per plot compared to the check TME 30572 with 52 of such roots/tuber per plot. Superior forage production capacity was demonstrated by 96/0603 and 94/0561 which produced 46.47 tons/ha and 41.67 tones/ha respectively while the highest root/tuber yield of 40-50 tones/ha was produced by the clones 97/2205, 96/0603, 95/0289 and TME 30572. It is concluded that most of the clones evaluated performed well with capacity to produce high quantities of forage to support livestock production. Cassava growers are therefore advised to source planting materials from clones 97/2205, 96/0603, 94/0039, 91/02324, 95/0289, 94/0026, 97/3200, 95/0166, TME30572 which have high tuber yield and high forage production capacity to generate additional revenue from the sale of forage/hay.