Aspects of the physiological basis of cultivar differences in yield of potato under droughted and irrigated conditions
Comparisons were made between droughted and irrigated crops in two field experiments conducted on cultivars of potato understood to exhibit a range of drought tolerance to identify important physiological attributes for drought tolerance. Drought reduced total dry matter production and tuber yields and increased tuber dry matter concentration. The better yield response of Désirée was due largely to the greater water content of its tubers. There were differences between cultivars in the number of tubers produced per unit area and in 1984 there were differences between treatments.
Functional differences in canopy growth were revealed in differences in the fractions of incident solar radiation which were intercepted.
The effects of drought were proportioned between components of yield, the principal effects being upon interception of solar radiation and on tuber dry matter concentration. Tuber number was an important factor influencing ware yield.
Effect of rainwater harvesting with ridge and furrow on yield of potato in semiarid areas
A new planting pattern for potato production in semiarid areas was designed and tested for enhanced tuber yield and for the benefit of collecting rainwater. This pattern comprised two elements: the ridge mulched by plastic film that acts as the runoff area and the furrow as the infiltration basin or planting area. The conventional planting pattern for potato production in semiarid regions of northwestern China is the opposite with mulched ridges for planting and the furrow as an infiltration zone. The purpose of this study was to examine the effect of the ridge with or without mulching on rainwater harvesting and the response in potato yield and to determine the optimal cross-sectional area of the ridge and furrow. A ratio defined as the width of the ridge to the width of the furrow or the planting area was used to evaluate the cross-sectional area. Three ratios of 0.5, 0.75, and 1.0 were tested under the conditions of mulched ridge, bare earth ridge, and no ridge or flat planting, respectively. No matter what ratio used, the width of the planting belt was the same at 0.6 m. The results showed that for tuber yield, the ridge with the plastic mulching was more effective than the bare earth ridge and that the bare earth ridge was better than flat planting. In the mulched ridges, a ridge width of 0.45 m or a ratio of ridge to furrow of 0.75 led to higher yield than that of ridges with a width of 0.3 and 0.6 m. For the bare earth ridges, the yield in the 0.6 m ridge width was higher than that of the other two ridges. Besides improving potato yield, the mulched ridge and furrow planting had the added advantage of collecting considerable rainwater for soil moisture. In addition, the percentage of small-sized potatoes was low. Therefore, we recommend that the mulched ridge with a ridge width of 0.45 m and a furrow width of 0.6 m as a successful method to increase potato yield in semiarid areas where potato production relies totally on rainwater. 
Effect of drip tape placement depth and irrigation level on yield of potato
Subsurface drip irrigation (SDI) is the most advanced method of irrigation, which enables the application of the small amounts of water to the soil through the drippers placed below the soil surface. One of the most commonly discussed aspects of SDI system is installation depth of drip lateral. Determining the appropriate depth of installation involves consideration of soil structure, texture, and crop’s root development pattern. Site-wise and crop-wise variations of these parameters preclude the possibility of framing general recommendations for installation depths of SDI system. An experiment was conducted on potato (var. Kufri Anand) during October–February for 3 years (2002–2003, 2003–2004 and 2004–2005) to study the effect of depth of placement of drip tape and different levels of irrigation application on potato yield. Drip tapes were buried manually in the middle of different ridges. Tests for uniformity of water application through the SDI system were carried out in the month of October every year. Three different irrigation levels of 60, 80 and 100% of the crop evapotranspiration and five depths of placement of drip tape namely, 0.0, 5.0, 10.0, 15.0 and 20.0 cm were maintained in the study. The coefficient of variation (CV) of flow rates was found 0.046, 0.047 and 0.064 during 2002–2003, 2003–2004 and 2004–2005, respectively. The low CV indicated good performance of the SDI system throughout the cropping season. The values of statistical uniformity (SU) and distribution uniformity (DU) were more than 92.0% during all the three cropping seasons. Soil water distribution at different growth stages of potato under different depths of placement of drip tape for varying irrigation levels was monitored. When drip tape was placed at surface and buried at 5.0 cm soil depth, upward movement of water takes place, 21.5% soil water content was found throughout the crop season of potato. When drip tape was buried 10.0, 15.0 and 20.0 cm below the surface, upward water movement due to capillary forces was not sufficient and soil surface remained relatively dry. 
Sweet Potato (Ipomoea batatas) Yield Parameters, Soil Chemical Properties and Cost Benefit Ratios Following Incorporation of Poultry Manure and Inorganic NPK Fertilizers in Low Nutrient Ghanaian Soils
The impact of sole poultry manure (6t PM ha-1), sole NPK (200kg NPK ha-1) and their combinations (3t PM + 100kg NPK ha-1 and 1.5t PM + 150kg NPK ha-1) on sweet potato yield parameters and soil nutrients was assessed at Adiembra and Fiaso in Ghana between June, 2011 to November, 2011 using RCBD. Nutritional levels of the sweet potato tubers and the amended soils were analysed with standard laboratory procedures. The 3t PM + 100kg NPK ha-1 produced significantly (P=0.05) the highest tuber yield (tonnes ha-1), tuber length and diameter, and also had the highest percentage of marketable tubers. The total percentage soil nitrogen, organic matter, Total Base Saturation (TEB) and Effective Cation Exchange Capacity (ECEC) were significantly (P=0.05) highest in the 6t PM ha-1 treatment. The 6t PM ha-1 treatment had the highest tuber nutrient values for Ca, Mg, P, S and N. The 3t PM + 100kg NPK ha-1 had the highest cost benefit ratios of 1:4.38 and 1:8.15 at Adiembra and Fiaso respectively. The results demonstrated that combined application of PM and NPK increased sweet potato tuber yield and soil nutrient levels in a cost effective manner. 
Evaluation of Potato Varieties against Salinity Stress in Bangladesh
Aims: The main aim of this study was to find out the salinity tolerant varieties of potato and to evaluate the growth and yield performance of potato varieties under different salinity level.
Study Design: The experiment was laid out in the two factor completely randomized design (CRD) with the three replications.
Place and Duration of Study: A pot experiment was conducted at the Horticulture Research field and Horticulture Laboratory of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh during December 2011 to April 2012.
Methodology: The possible combination of the ten potato varieties (Diamant, Lady Rosetta, Provento, Felsina, Granola, Asterix, Cardinal, Sagita, Shilbilati and LalPakri) and the four levels of salt (NaCl) (So= 0.50 dS/m, S1= 3.25 dS/m, S2= 6.95 dS/m and S3= 8.90 dS/m) were considered as the treatment variables. There were 120 earthen pots and the tubers of selected genotypes were planted in each pot. After 20 days of planting treatment was applied and irrigated every two days interval. 2 ds/m and 6 ds/m saline water was used to raise 0.5 ds/m and 3.25 ds/m respectively. To reach 6.95 ds/m first fifteen days pots were irrigated at 6 dS/m and then 8 ds/m at 2 days interval. Similarly, pots were irrigated at 6 ds/m (first 7 days) and 8 ds/m (next 7 days) and then 12 ds/m to reach 8.90 ds/m at the same interval to avoid osmotic shock. Finally, the electrical conductivity of the soil against treatment reached and measured by Electrical Conductivity meter. It was taken 30 days to raise the soil salinity up to the treatment. These levels of salinity were maintained up to final harvest. After harvesting some important physiological, and yield contributing attributes such as chlorophyll content, membrane leakage, ion uptake and tuber weight were measured.
Results: In respect of leaf chlorophyll content, membrane leakage, per plant tuber weight, and ion uptake were better in Sagita and Felsina. The variety Sagita followed by Felsina had less membrane injury upto 32.14% where as Shilbilati and Lalpakri exhibited upto 69.45% membrane injury at 6.95 dS/m of salinity. At the same time, Sagita gave the highest yield followed by Felsina, Lady Rosetta and Provento.
Conclusion: Finally, the present results revealed that variety Sagita and Felsina responded well under salinity stress condition. Lady Rosetta and Provento performed moderately at 6.95 dS/m. The varieties Shilbilati and Lalpakri were salt sensitive among the selected genotypes 
 Jefferies, R.A. and MacKerron, D.K.L., 1987. Aspects of the physiological basis of cultivar differences in yield of potato under droughted and irrigated conditions. Potato Research, 30(2), pp.201-217.
 Tian, Y., Su, D., Li, F. and Li, X., 2003. Effect of rainwater harvesting with ridge and furrow on yield of potato in semiarid areas. Field Crops Research, 84(3), pp.385-391.
 Patel, N. and Rajput, T.B.S., 2007. Effect of drip tape placement depth and irrigation level on yield of potato. Agricultural water management, 88(1-3), pp.209-223.
 Agyarko, K., Dapaah, H.K., Buah, S. and Frimpong, K.A., 2013. Sweet potato (Ipomoea batatas) yield parameters, soil chemical properties and cost benefit ratios following incorporation of poultry manure and inorganic NPK fertilizers in low nutrient Ghanaian soils. International Journal of Plant & Soil Science, pp.129-138.
 Munira, S., Hossain, M.M., Zakaria, M., Ahmed, J.U. and Islam, M.M., 2015. Evaluation of potato varieties against salinity stress in Bangladesh. International Journal of Plant & Soil Science, pp.73-81.