Genotypic variation in fresh root colour, harvest period and dry matter content of improved cassava genotypes Njoku, D.N; Egesi, C.N; Vernon, G; Offei, S.K; Asante, I and Kulakow, P

Introduction White cassava varieties are low in beta-carotene but high in dry matter content. Newly introduced yellow cassava varieties high in beta-carotene are usually very low in dry matter content and this may affect adoption. development of higher B-carotene cassava in Nigeria will contribute to: 1. a sustainable solution of vitamin A deficiency already identified among regular cassava consumers in Nigeria. 2. market potential of cassava as food and feed can be enhanced. 3. other by-products or value -added products of cassava such as chips, starch, gari, bio-fuel and bio-fertilizer can provide employment opportunity and economic empowerment to agricultural sub-sector in Nigeria.

Objectives This study was undertaken to screen some selected genotypes in NRCRI cassava germplasm with a view to: determine total carotene content dry matter content compare the spectrophotometric and standard colour chart methods of total carotene content determination available at NRCRI

Materials and Methods 8 cassava genotypes were planted at NRCRI Umudike in 2008. 5 genotypes have yellow fleshed root while 3 were white fleshed root. Harvesting were carried out at 11 and 13 MAP. Samples were prepared for analysis according to Harvest-Plus procedure. Visual observation using colour and total carotene content were determined spectrophotometrically, using the formula: A x volume (ml) x 104 TCC (μg/g) = ———————– A1%1cm x fresh sample weight (g)   where A= absorbance; volume = total volume of extract A 1%1cm = absorption coefficient of β-carotene in PE (2592). The dry matter was done by oven drying about 30g of the sample at 700C until no moisture remains and a constant weight was obtained. %DMC = dry weight of sample x 100. fresh weight

Results and Discussion

Fig 1: dry matter content of cassava genotypes at different harvesting periods

Fig 2: Relationship of total carotene with dry matter content

Fig 3: Relationship of total carotene with CMD

Conclusion Carotene content of cassava roots screened with available standard colour chart and Spectrophotometer readings were positively correlated and also high. This demonstrate the potential of yellow roots cassava as contributing in overcoming vitamin A deficiency (VAD) found especially among daily consumers of cassava in Nigeria. Although delay harvesting may lead to an increase in carotenoid content, but it negatively affects dry matter content which may also affect adoption by farmers. So, there is need to overcome this challenge by breeders.

Acknowledgement References: Chavez et al, 2008; Esuma et al, 2012 Mrs. Njoku, Sylver Dr. Eke-okoro, ON Dr. Ceballos, H Mr. Alamu Dr. Akinbo, O Dr. Bunmi, O Onwuka Samual Ivory Chimaobi Dr. T.O. Ezulike References: Chavez et al, 2008; Esuma et al, 2012

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