Field experiments were conducted at Ebonyi State University, Faculty of Agriculture Research Farm Abakaliki, Nigeria during 2009/10 growing seasons to evaluate the effects of staking and planting dates on the grain/tuber yields of seven accessions of African yam bean (Sphenostylis stenocarpa, Hochst. Ex. A. Rich). The results indicated that all the African yam bean accessions performed better w...

We screened the pharmacological effects of a 50% ethanol extract of Yacon tubers and leaves on spermatogenesis in rats. As a result, we found that Yacon tuber extracts increased sperm number and serum testosterone level in rats. It has been reported that the crude extract of Yacon tubers and leaves contain phenolic acids, such as, chlorogenic acid, ferulic acid and caffeic acid by HPLC/MS analy...

INTRODUCTION In an extensive review of organic mulches applied on conventionally tilled (plow-disk) fields, Dutton (1957) concluded: 1) that organic mulches such ashay and straw often increasedboth yield and quality of Irish potato (Solanum tuberosum L.) and 2 ) that improved soil physical properties under the mulch, particularly lower soil temperatures and conservation of soil moisture, were r...

Maximum potato (Solanum tuberosum L.) tuber yields occur when an active plant canopy is maintained until normal plant maturation. Plaid nutrient concentrations and uptake rates play a major role in maintaining an active plant top. The objectives of this study were to relate the plant P concentrations to the P and dry matter balance between tuber and total plant growth needs. Growth analysis dat...

Modification of tuber carbohydrate metabolism by the tuber-specific expression of a yeast invertase targeted to the cytosol or apoplast has previously been demonstrated to have diverse effects on tuber growth and metabolism. In the current study, we generated plants exhibiting tuber-specific expression of the same enzyme targeted to the vacuole. Enzymatic analysis of the carbohydrate levels of ...

To define plant 'nutritional quality' for aphids, the causal basis of the variation in aphid performance between host plants of different developmental ages was explored using the aphids Myzus persicae and Macrosiphum euphorbiae on potato plants (Solanum tuberosum). Both aphid species performed better on developmentally young ('pre-tuber-filling') plants than on mature ('tuber-filling') plants....

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR, EC1.1.1.34), the key enzyme in isoprenoid biosynthesis, was purified from microsomes of potato tuber tissue, and a polyclonal antibody and two monoclonal antibodies against the purified enzyme were prepared. HMGR protein content was measured by immunotitration and radioimmunoassay using these antibodies. HMGR activity was very low in the fr...

Dormancy is one aspect of tuber physiological age that begins with potato tuber initiation. During dormancy, biochemical and physiological processes do occur but they do not trigger immediate morphological changes, yet these processes are relevant for the number of sprouts produced after breaking of the dormancy and for the growth vigour of the seed tuber. This review article reports that dorma...

Nitrogen fertilizer applications, for maximum fertilizer efficiencies and crop yields, should be based on the N required by the crop during its various growth stages. The objectives of this paper were to identify the N requirements of the potato plant (Solarium tuberosurn L.) during growth and to evaluate selected soil and plant tissue tests as indicators of the plant's N status. Growth analysi...