Growth and Yield Response of Improved Sweet Potato (Ipomoea batatas (L.) Lam) Varieties to Different Rates of Potassium Fertilizer in Calabar, Nigeria

Abstract

A two-year field study was conducted during the growing seasons of 2007 and 2008 in Calabar, south eastern Nigeria to evaluate the response of two improved sweet potato varieties (TIS 8164 and Ex-Igbariam) to five rates (0, 40, 80, 120 and 160 kg K/ha)of potassium fertilizer. Factorial combinations of the treatments were arranged into a randomized complete block design with three replications. Results showed that Ex-Igbariam was more responsive to K application than TIS8164 as indicated by the production of longer vines, higher number of leaves and branches/plant and heavier vine dry weight at all the applied K rates. Averaged across the two years, revealed that Ex-Igbariam out-yielded TIS8164 by 12.5, 12.7 and 13.3% for number of tubers/plant, weight of tubers/plant and tuber yield/ha, respectively. Application of K at the highest rate (160 kg/ha) significantly (P<0.05) increased vine length, number of leaves and branches/plant, whereas dry weight of vine, diameter of tubers/plant and weight of tubers/plant were statistically similar at 120 and 160 kg K/ha rates. Number of tubers/plant and tuber yield/ha peaked at 120 kg K/ha and 160 kg K/ha, respectively. Aggregate tuber yield/ha obtained at 120 and 160 kg K/ha rates were more than 7 and 8 times, respectively higher than the control treatments. Potassium fertilizer application at 120 to 160 kg/ha appeared appropriate for optimum yield for Ex-Igbariam in the study area and is therefore recommended.

Morpho-Physiological Evaluation of Sweet Potato (Ipomoea batatas L.) Genotypes in Acidic Soil

“…This might be due to the variation of genetic makeup of the different sweet potato genotypes. The results obtained from the present study are consistent with the results of Rashid et al (2002) and Uwah et al (2013) who stated that the numbers of storage root plantG 1 were found considerable variation. Farooque and Husain (1973) also showed that the storage roots number plantG 1 varied from 4.70-11 and it depends on the genotypes of sweet potato.…”

“…The variation was found among the genotypes both in the genetical and growth characteristics. The agreement of the present study closely related to the findings of Uwah et al (2013) who reported that the length of storage root plantG 1 in two years ranges from 14.4-16.3 cm. Rashid et al (2002) and Farooque and Husain (1973) showed that the length of the storage roots differed among the varieties.…”

Effect of Graded Levels of Nitrogen and Potassium on Yield and Quality of Sweet Potato (Ipomoea batatas L.)

“…But specific gravity (1.14 g ml -1 ) of tuber is increased with decreased nitrogen level. Graded levels of potassium application is significantly increases tuber yield (19,597 kg ha -1 ) and yield contributes are tuber diameter (5.96 cm), tuber length (17.94 cm), number of tubers per plant (9.0) are recorded in the application of 100 kg K 2 O ha -1 and quality attributes are fresh tuber weight (410.26 g), reducing sugar (0.231 %), non reducing sugars (6.23 %), total sugar (6.46 %), TSS (12.69 %), carbohydrates (17.29 %), protein (8.70 %) and specific gravity (1.12 g ml -1 ) of tuber was found @ 100 kg K 2 O ha -1 over control application (K 0 Uwah et al, (2013).…”

Sweet potato response to low-input agriculture and varying environments of KwaZulu-Natal, South Africa: implications for food security strategies

“…Information about incorporation of farmers' knowledge in the production of the crop is necessary. Most of the released sweet potato varieties have been evaluated on research farms Njoku et al 2007;Egbe & Idoko 2009;Uwah et al 2013) where the growth environment is supplemented with irrigation, fertilizers and pest and disease control. This article not only reports on the evaluation of locally bred sweet potato cultivars grown on resource-constrained small-scale farms but also provides information on the plant's physiological responses to growth environment and how it (environment) affects plant growth and yield of sweet potato.…”