Highest Tuber Yield Research Articles

Rhizosphere Engineering for Improving Productivity and Quality Constituents In Asparagus Racemosus

The medicinal crop, Asparagus racemosus is valued for its tuberous roots that are used in medicinal and tonic preparations. Root is diuretic and galactogouge. Its demand is ever increasing as it is indispensable for ayurvedic medicine manufacturing units for the formulation of umpteen drugs and neutaceuticals. An experiment was conducted to standardize the eco-physiological requirements for sustainable utilization of natural resources and cultural inputs to achieve higher productivity without affecting the quality of officinal parts. The experiment was conducted in Factorial RBD with two replication. The technical programme consisted of combinations of six containers, viz, Polythene bags bags partially buried in soil, empty cattle feed bags partially buried in soil, micro site enrichment with lining, micro site enrichment without lining, pit followed by mound and control, two rooting medium, viz,special rooting medium for root induction and root development and control; and two soil moisture levels, viz, rain fed condition and irrigated condition. The experiment was continued for eighteen months and vine length, number of branches, yield and yield attributes, viz, number, length and girth of tubers were recorded and biochemical constituents estimated. Economic analysis of the system was carried out. Cultivation of Asparagus under irrigated condition in empty cattle feed bags filled with enriched rooting medium and partially buried in soil recorded the highest tuber yield and enhanced gross income, profit and benefit cost ratio besides improving quality attributes like osmotic potential and oleoresin.

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Potato late blight is one of the major constraints to potato cultivation in the north eastern hill region of India. Eight popular potato cultivars (Kufri Girdhari, Kufri Megha, Kufri Himsona, Kufri Himalini, Kufri Giriraj, Kufri Jyoti, Kufri Kanchan and Kufri Shailja) were evaluated for late blight disease progress and yield potential with or without the application of fungicide in the field. Blight appeared 103 days after planting (DAP) in Kufri Girdhari and 89 DAP in Kufri Megha in sprayed and unsprayed plots. Minimum terminal disease severity was recorded in Kufri Girdhari (6.5 and 7.5%) followed by Kufri Megha (22.5 and 35%), Kufri Himsona (62.5 and 70%) and Kufri Himalini (70 and 75%) in sprayed and unsprayed plots, respectively. Area under the disease progress curve was lowest on Kufri Girdhari (22.75 and 26.25) followed by Kufri Megha (253.75 and 402.5), Kufri Himalini (934.5 and 1333.5), Kufri Himsona (813.75 and 1162), Kufri Giriraj (1347.5 and 2082.5), Kufri Jyoti (1382.5 and 2117.5), Kufri Kanchan (1277.5 and 1951.25) and Kufri Shailja (1333.5 and 2073.75) in sprayed and unsprayed plots, respectively. There was no significant difference in areas under disease progress curves (AUDPCs) and yield of sprayed and unsprayed plots of Kufri Girdhari, whereas, significant differences (cultivar and spray) were recorded in Kufri Megha, Kufri Himalini and Kufri Himsona. The highest tuber yield was obtained in Kufri Girdhari (34.08 t/ha) and Kufri Himalini (33.48 t/ha). The study revealed that Kufri Girdhari gave highest yield with and without fungicidal applications.   Key words: Late blight, Phytophthora infestans, Solanum tuberosum disease severity, fungicidal spray, cultivars, yield.

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Little is known about the effects of nitrogen supply on plant productivity and defensive response to pathogen exposure. Here, tuber yield and resistance to the fungal pathogen Phytophthora infestans were investigated in potato plants supplied with four different nitrogen levels (N1: 45 kg-hm-2, N2: 90 kg-hm-2, N3: 135 kg-hm-2, and N4: 180 kg-hm-2). The N2 level of nitrogen promoted the highest tuber yield and largest tubers under pathogen-free conditions. However, N3 promoted the strongest pathogen resistance and highest potato production in response to P. infestans exposure. Also, the highest level of chlorophyll accumulation was observed with N3 relative to the other treatment groups under pathogen-infected but not pathogen-free conditions. Further study showed that, in response to pathogen infection, the N3 level of nitrogen induced the highest activity levels for the defensive enzymes polyphenol oxidase and phenylalanine ammonia-lyase (but not chitinase and β-1,3-glucanase) and the most abundant accumulation of phenolic and flavonoid compounds. Our data demonstrated that modest increases in the nitrogen supply provided potato plants with optimum growth and defensive capability in response to P. infestans exposure. Key words: Nitrogen, tuber yield, pathogen resistance, Phytophthora infestans, Solanum tuberosum.

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This study was done to determine the effect of initial node strength on dry matter yield of cassava. Studies were conducted at the Waterloo Research Campus, University of Trinidad and Tobago using the sets of Mexican variety (Mx) at 6 months with 1 to 3 nodes, 4 to 9 cm, and dry matter of 6 to 15 g/set. The crop was established at 60 × 80 cm and treated with a compound NPK fertilizer. Growth analysis (functional approach) was carried from 20 to 340 Days after emergence (DAE), and the best fit polynomial regression applied. The results indicated that tuberization started after 120 DAE and tuber dry weight increased with increasing set size (YTDW = -1177 + 9.90D - 1.26-2 D2 + 37.7N2). The 3 node sets produced (P > 0.05) the highest tuber yield. The leaf area ratio (LAR) showed (P > 0.001) a quadratic response (Ylar = 12.8 - 1.94 H - 2.39 N + 0.08 H2 + 0.18 N*H), peaked at 2 g/cm2/day1, and declined at harvest. Both the net assimilation rate (NAR) and the relative growth rate (RGR) were not affected by the number of nodes, however, the NAR peaked 0.046 g/m2/day at 60 DAE. The initial strength of 3 nodes sets proved to be superior to the single node sets. Key words: Cassava, growth analysis, tuberization, nodes, sets.

Effect of different irrigation regimes on yield, water use efficiency and quality of potato (Solanum tuberosum L.) in the lowlands of Tashkent, Uzbekistan: A field and modeling perspective

In the lowlands of Central Asia, summer grown potato is increasingly affected by soil moisture deficit due to inadequate irrigation and high evaporative demand. Many farmers cannot apply irrigation schedules that fully respond to the water demand because of reduced water availability throughout the Aral Sea basin, caused by global warming, and the competing use of irrigation by the cotton crop. The effects of different irrigation regimes were evaluated on ten potato clones in the lowlands of Tashkent, Uzbekistan, during the summer cropping season (July–October) of three consecutive years (2008, 2009 and 2010). The applicability of a growth model to predict yield under the different water regimes was tested. Significant treatment and genotype effects on yield and yield components were observed. The significant correlation for tuber yield among treatments suggested that yield under water limitation was driven more by potential yield than water restriction tolerance. Tuber yield was more associated to tuber weight than to tuber number, a component already largely determined when the different water treatments were initiated. The reduction of water supply after tuberization had a limited effect on yield and consequently drastically enhanced water use efficiency. It increased starch and dry matter content, but decreased vitamin C content. Some clones maintained high yield across years and treatments and appeared as good candidates for being recommended to farmers. Others showed interesting quality traits and are proposed for use as progenitors in breeding programs targeting at the improvement of the nutritional value of potato. A good prediction of yield was obtained using the growth model except for year 2009 when trials were heavily affected by weed infestation. The present study contributes to the improvement of water management and the identification of clones with high tuber yield and quality for the lowlands of Tashkent. Additional experiments are required to address the constraints to potato cultivation in other agro-climatic zones of Central Asia.

Yield and yield components response of potato genotypes in selected agro-ecologies of Rwanda

Potato (Solanum tuberosum L.) is an important food security crop in Rwanda but its productivity is low at 9 t/ha. In the past, the major potato research and development focused on seed production and distribution without targeted breeding to enhance productivity. The objective of this study was to determine yield and yield components response of potato genotypes in selected agro-ecologies of Rwanda to identify breeding parents. Fifteen agronomically stable genotypes were evaluated during 2011 at three locations: Kinigi, Rwerere and Nyamagabe with a randomised complete block design using three replications. Data were collected on yield and yield components. Further, a number of flower and tuber characteristics such as flower colour, pollen production, tuber shape, tuber flesh and skin colour, and depth of eyes were recorded. Across locations, genotype Kigega had the highest tuber yield at 32.4 t/ha, followed by Ngunda (32.3 t/ha) and Kirundo (26.9 t/ha), whereas Mabondo had the lowest yield (10.8 t/ha). At Nyamagabe genotype Kivu had the highest tuber yield of 16.7 t/ha, while Kinigi displayed the lowest at 1.8 t/ha. Genotype Ngunda was excellent yielder at Kingi with 47.2 t/ha tuber yield, while Bineza yielded low at 2.2 t/ha. At Rwerere, genotypes Victoria and Kigega were the best yielders at 45.7 and 44.7 t/ha, respectively, while Mabondo was the least yielder with 13.1 t/ha. Overall, the study identified potential breeding parents including genotypes Ngunda, Kirundo, Gikungu, Kigega, Victoria, Nderera and Bineza on the basis of medium to high responses for yield, desirable tuber characteristics and productive flowers for crosses. Location had strong effect on trait expression and contributed as the main source of variation. Genotypes Kigega and Kirundo had stable performance across locations in Rwanda. There is a need to develop potato varieties for specific agro-ecological adaptation in Rwanda.

Effects of seaweed saps on soil health and productivity of potato (Solanum tuberosumL.)

A field experiment was conducted during the rabi season of 2012–13 at Raipur to study the effects of seaweed saps on yield, nutrient uptake and nutrient use efficiency of potato (Solanum tuberosum L.) and soil fertility status in Inceptisol of Chhattisgarh. Foliar spray was applied thrice at different concentrations (0, 2.5, 5.0, 6.25, 7.5, and 10.0% v/v) of seaweed extracts, viz. Kappaphycus and Gracilaria. Foliar applications of seaweed extract significantly enhanced the yield, nutrient uptake and soil fertility parameters. The highest tuber yield was recorded with the application of 10% Gracilaria Sap + recommended dose of fertilizer (RDF), followed by 10% Kappaphycus Sap + RDF extract resulting in an increase by 11.31 and 9.38% tuber yield, respectively comparedto the control (water spray +RDF). The highest NPK uptake by tuber and haulm were observed under 10% Gracilaria Sap + RDF. After the harvest of the crop indicated maximum available N (265.51 kg ha−1) and available K (389.39 kg ha−1) was observed under 10% Gracilaria Sap+ RDF. Higher values of available P (11.77 kg ha−1) was recorded with 6.25% Kappaphycus Sap + 50% RDF.

Efficacy of Chemical Weed Control in Potato (Solanum tuberosum L.)

In this paper the results of efficiency of combined application of six herbicides in weed control in potato were presented. The study was done during 2007 and 2008 in Kolašin, on acid brown soil, at an altitude of about 900 m. In the experiment the following herbicides were examined: S-metalachlor, Bentazone, Acetohlor, Flurochloridone, Metribuzin and Dimetenamid-P. The study was conducted in the Kennebec variety crop. All applied herbicides had satisfactory effect in decreasing number and biomass of weeds. As the most effective variants in two-year average, Sencor 70 WP and Genius were expressed (95 and 94% for the number and 92 and 88.8% for weed biomass) and the weakest effect had combination of Dual Gold 960 EC + Basagran (82.3; 69.4, respectively). In all investigated combinations of herbicides significantly higher tuber yield was achieved comparing to the control. The highest yield of tubers was measured in variant where Acenit 800 EC was applied - 33 t ha-1, while the lowest yield had the control variant - 18.4 t ha-1.

Эффективность применения возрастающих доз минеральных и органических удобрений при выращивании картофеля в условиях лесостепи Среднего Поволжья

The article titles the role of mineral nutrition in the formation of the potato crop of Aroza variety on gray forest soils. During the research years the highest tuber yield on average was obtained 22.56 tons per hectare while treatment by ZHUSS -1 for the treatment of tubers before planting and ZHUSS -2 for conjunction with foliar fertilizers at a dose N150, P150, K150. The yield increased in this variant to 12.89 tons per hectare. The significant fluctuations in productivity of potato Aroza variety were revealed on gray forest soils due to climatic factors. In 2010 dry year the yield ranged from 7.10 tons per hectare up to 12.10 tons per hectare against 80 tons per hectare of organic fertilizers. In humid provided 2012 year, it amounted up 11.43 tons per hectare to 28.87 tons per hectare in the way of application of ZHUSS-1 for the treatment of tubers before planting and ZHUSS-2 in conjunction with foliar fertilizers at a dose N150, P150, K150. 16.90% of nitrogen, 8.27% of phosphorus and 20.03% of potassium were used from the potato plant soil. The fertilizer, depending on the dose were introduced at the following amount: 43,05-43,74% of nitrogen, 15,68-18,06 % of phosphorus, 70,05-75,26 % of potassium. As for the organic fertilizer, the plants have learned 17,34-20,28% of nitrogen, 15,19-17,38% of phosphorus and 25,68-31,31% of potassium. Despite the increase in costs with increasing doses of fertilizers, the highest net income 73001 rubles per hectare and the level of profitability - 106.65% were obtained at the option of applying ZHUSS -1 for the treatment of tubers before planting and ZHUSS -2 in conjunction with foliar fertilizers in N150, P150, K150 dose . In this version there was the lowest cost - 3034 rubles per ton.

Comparative Proteomics Reveals a Role for Seed Storage Protein AmA1 in Cellular Growth, Development, and Nutrient Accumulation

Seed storage proteins are known to be utilized as carbon and nitrogen source for growing seedlings and thus are considered as potential candidates for nutritional improvement. However, their precise function remains unknown. We have earlier shown that ectopic expression of a seed storage protein, AmA1, leads to increase in protein besides high tuber yield in potato. To elucidate the AmA1-regulated molecular mechanism affecting increased protein synthesis, reserve accumulation, and enhanced growth, a comparative proteomics approach has been applied to tuber life-cycle between wild-type and AmA1 potato. The differential display of proteomes revealed 150 AmA1-responsive protein spots (ARPs) that change their intensities more than 2.5-fold. The LC-ESI-MS/MS analyses led to the identification of 80 ARPs presumably associated with cell differentiation, regulating diverse functions, viz., protein biogenesis and storage, bioenergy and metabolism, and cell signaling. Metabolome study indicated up-regulation of amino acids paralleling the proteomics analysis. To validate this, we focused our attention on anatomical study that showed differences in cell size in the cortex, premedullary zone and pith of the tuber, coinciding with AmA1 expression and localization. Further, we interrogated the proteome data using one-way analysis of variance, cluster, and partial correlation analysis that identified two significant protein modules and six small correlation groups centered around isoforms of cysteine protease inhibitor, actin, heat shock cognate protein 83 and 14-3-3, pointing toward AmA1-regulated overlapping processes of protein enhancement and cell growth perhaps through a common mechanism of function. A model network was constructed using the protein data sets, which aim to show how target proteins might work in coordinated fashion and attribute to increased protein synthesis and storage reserve accumulation in AmA1 tubers on one hand and organ development on the other.

Genetic Diversity of Cassava (Manihot esculenta Crantz) Genotypes in Ethiopia

The experiment was conducted at Jimma Agricultural Research Centre . The objective of the experiment was to evaluate the genetic diversity of cassava using agronomic traits so as to characterize and cluster with in collected cassava genotypes. Thirty five cassava genotypes were sampled from the collection. Relatively high broad sense heritability was observed for plant height (42.08) and root diameter (31.88) indicating the existence of possibility for selection of genotypes for high fresh tuber weight. The clustering of genotypes based on 11 quantitative traits revealed the existence of five distinct groups. The maximum inter cluster distance was observed between genotypes under cluster II and V and I and V, hence, the genotypes grouped in these clusters could be used for crossing if high fresh tuber yield genotypes are planned in breeding program.

Effect of Harvest Date on PI2, Total Protein, TGA Content and Tuber Performance in Potato

Proteinase inhibitor 2 (PI2), isolated from potatoes is associated with the release of cholecystokinin (CCK), a satiety factor in humans. PI2 is the active ingredient of Slendesta® Potato Extract. The effect of harvest date on the levels of proteinase inhibitor 2 (PI2), total protein content and total glycoalkaloids (TGA) was studied in two potato (Solanum tuberosum L.) clonal lines. In addition, tuber specific gravity, tuber yield, and tuber size distribution were measured in response to harvest date. The two potato clonal lines designated as KI-PSt0018 and KI-PSt0034 were planted in a randomized complete block design with four replicates. Tubers were harvested at four different dates during the growing season; 4 weeks and 2 weeks to vine-kill; at vine-kill; and 2 weeks post vine-kill. Sample tubers from these four harvest dates and from 2 months of storage, post vine-kill stage were analyzed for PI2, total protein and TGA. Harvesting at different dates had a significant influence on most of the traits studied in both clonal lines. The two clonal lines responded differently to different harvest dates for all traits except PI2 and specific gravity. PI2 levels increased with maturity with the highest levels observed at full maturity in both clonal lines. The protein levels did not show any specific trend in either clonal line. TGA levels increased gradually in small increments with maturity in KI-PSt0018 but did not have a clear pattern in KI-PSt0034. Tuber yield and size increased with maturity of the crop in both clonal lines. Higher tuber yields were seen during final vine-kill and 2 weeks post vine-kill compared to the earlier stages of harvest in both clonal lines. Tuber specific gravity declined when tubers were left in the ground for 14 to 21 days after vine-kill in both clonal lines. This study indicated harvest of potato prior to vine-kill is not beneficial for the extraction of PI2 for use as functional food or dietary supplement ingredient.

Germplasm diversity and differentiation ofHelianthus tuberosusL. revealed by AFLP marker and phenotypic traits

SUMMARYHelianthus tuberosusL. is regarded as one of the most important bioenergy crops because of its tolerance to arid conditions and its high biomass production. Future breeding programmes will rely on the available germplasm, thus necessitating a critical assessment of genetic diversity and differentiation in the species. The germplasm diversity and regional differentiation ofH. tuberosusL. was assessed for 60 accessions collected from East Asia and Europe by means of amplified fragment length polymorphisms (AFLPs), phenotypic traits and chemical analysis. The analysis did not reveal separate clusters for accessions from East Asia and Europe, with 5% for genetic and 0·27% for phenotypic variability, although some regional accessions were closely related to each other with respect to morphological, chemical and genetic variation. Both phenotypic and genetic relationships showed a moderate correlation with colour of tubers, which can be used as an important criterion for germplasm management of the crop. Three major genetic groups were identified from the accessions. Within the groups derived from the genetic data, both morphological and chemical traits were very variable. The most important features of Groups I, II and III were: Group I, strong sexual reproduction, higher above-ground biomass and nutrient content; Group II, longer vegetative growth; Group III, higher tuber yield and total sugar content. High diversity was found in both European and East Asian accessions as well as within each genetic group, suggesting that there is a strong base for future breeding from these plants.

Thermogravimetric and kinetic analysis of energy crop Jerusalem artichoke using the distributed activation energy model

Jerusalem artichoke has great potential as future feedstock for bioenergy production because of its high tuber yield (up to 90 t ha(-1)), appropriate biomass characteristics, low input demand, and positive environmental impact. The pyrolytic and kinetic characteristics of Jerusalem artichoke tubers were analyzed at heating rates of 5, 10, 20 and 30 A degrees C min(-1). TG and DTG curves in an inert (nitrogen) atmosphere suggested that there were three distinct stages of mass loss and the major loss occurs between about 190-380 A degrees C. Heating rate brought a lateral shift toward right in the temperature. And, it not only affects the temperature at which the highest mass loss rate reached, but also affect the maximum rate of mass loss. The distributed activation energy model (DAEM) was used to study the pyrolysis kinetics and provided reasonable fits to the experimental data. The activation energy (E) of tubers ranged from 146.40 to 232.45 kJ mol(-1), and the frequency factor (A) changed greatly corresponding to E values at different mass conversion.

Effects of non-chemical and chemical fertilizers on potato (Solanum tuberosum L.) yield and quality

In order to investigate the effects of natural and chemical fertilizers on yield and quality of potato, a study was conducted at the Agricultural Research Farm of Razi University, Kermanshah, Iran. The experiment was a factorial with three factors arranged in a randomized complete block design with four replications. The first factor was tuber inoculation with Nitragin biofertilizer (a combination of Azotobacter species and Azospirillumspecies) at two levels: non inoculated and inoculated. The second factor was HB-101 (a completely organic natural extract) with three levels: non sprayed, one time and two times sprayed onto the potato foliage during the growing season. The third factor was chemical urea fertilizer with two levels: non-used (0) and used at rate of 500 kg/ha. The results showed that the factors had significant effects on tuber yield, tuber weight, the number of tuber per plant, biological yield, harvest index, and tuber nitrate content of potato. The highest tuber yield and the number of tuber per plant were obtained when the tubers were inoculated with Nitragin; urea was used and HB-101 was sprayed two times. Moreover, the lowest tuber nitrate content was obtained when HB-101 was sprayed two times and the tubers were inoculated with Nitragin biofertilizer. It is concluded that integrated application of natural and biological fertilizers along with urea can be useful to enhance potato yield and quality. Key words: Biofertilizer, HB-101, Nitragin, potato, quality, yield.

Effect of multi-nutrient complex fertilizers on growth and tuber yield of very early potato (Solanum tuberosum L.) cultivars

The aim of the study was to compare the effect of multi-nutrient complex fertilizers (HydroComplex, Nitrophoska Blue Special and Viking 13 from the nitrophoska group, and Polimag S from the amophoska group) and single-nutrient fertilizers on the growth and tuber yield of very early potato cultivars (‘Aster’, ‘Fresco’, ‘Gloria’). The field experiment was carried out on podzolic soil in mid-eastern Poland during 2005–2007. The study showed a greater beneficial effect of HydroComplex and Nitrophoska Blue Special on the growth of very early potato cultivars than that of Viking 13 and Polimag S. The application of HydroComplex and Nitrophoska Blue Special resulted in greater above-ground plant biomass and assimilation leaf area compared with single-nutrient fertilizers; the leaf area index (LAI) was higher by 0.28 and 0.32, respectively. The differences were smaller and not statistically confirmed with the use of Polimag S and Viking 13. When the multi-nutrient complex fertilizers were applied, leaf weight ratio (LWR), leaf area ratio (LAR) and specific leaf area (SLA) were similar to the single-nutrient fertilizers. Of the multi-nutrient complex fertilizers, only Nitrophoska Blue Special resulted in higher tuber yield, on average by 2.40 t × ha<sup>-1</sup>, compared with the single-nutrient fertilizers. The studied cultivars showed a similar response to applied fertilizers. LAI for ‘Gloria’ was higher than for ‘Aster’ and ‘Fresco’, with smaller LAR found in ‘Gloria’. LWR for ‘Fresco’ was smaller than for ‘Aster’ and ‘Gloria’, with higher SLA found in ‘Fresco’. The tuber yield of ‘Aster” (24.04 t × ha<sup>-1</sup>) was higher on average by 3 t × ha<sup>-1</sup> than for ‘Fresco’ and ‘Gloria’.

Soil Macronutrients Influence Antioxidant Status in Early Season Potatoes

Potatoes, a good source of antioxidant can prove low cost supplement in Indian diet for Fig ht against malnourishment, which is presently growing at alarming rate. Qualitative parameters viz. antioxidants, starch, dry matter, secondary metabolites etc. in potato are influenced by genotype and environmental conditions. The antioxidants contents can be enhanced significantly by employing suitable variety, cultivation regimes and environmental stresses. Present research reports the identification of antioxidant affluent variety, effect of macronutrients on antioxidants content in tubers per say and compound antioxidants yield in short duration crop under heat stress condition. Among prevalent ten potato varieties, Kufri Surya was adjudged best with maximum ascorbic acid (20.4mg 100g FW−1) and carotenoids contents (44.0μg 100g FW−1) and moderate phenols in fully matured tubers. The results indicated that Kufri Surya tubers harvested at infancy (60 day) could achieve moderate levels of ascorbic acid (11.0 mg 100g FW−1), maximum phenols (59.9 mg 100g FW−1) and highest tuber dry matter (18.4%) with 240 kg N ha−1. Application of 240 kg N ha−1 had better tuber yield (9.2 t ha−1), highest total phenols yield (5.5 kg ha−1) and comparable ascorbic acid productivity (1.01 kg ha−1). Likewise, ascorbic acid and tuber dry matter were increased significantly by phosphorous and potash nutrients, whereas total phenols improved marginally. The highest tuber yield (8.9 t ha−1), compounded yield of ascorbic acid (1.51kg ha−1) and total phenols (4.98 kg ha−1) were harnessed with 60 kg P2O5 and 100 kg K2O ha−1. The findings suggest that macronutrients N, P2O5 and K2O applied @ 240, 60 and 100 kg ha−1, respectively were most appropriate levels for harnessing optimum antioxidants yield with >18.0% tuber dry matter in 60 days early crop of potato variety Kufri Surya.

Genotype and Environment Interaction and Marketable Tuber Yield Stability of Potato(Solanumtuberosum L) Genotypes Grown in Bale Highlands,Southeastern Ethiopia

Twelve potato (Solanumtuberosum L.) genotypes were evaluated using randomized complete block design (RCBD) with three replications to evaluate their genotype x environment interaction (GEI) and marketable tuber yield stability across nine environments during 2009-2011 at highlands of Bale, Southeastern Ethiopia. The combined analysis of variance (ANOVA) revealed that there was significant (p<0.05) variation in genotype x environment interaction in marketable tuber yield. Genotype, environment and genotype x environment interaction respectively explained 18.86%, 51.88% and 29.26% of the total sum of squares in marketable tuber yield (t/ha). Most of the total sum of squares in marketable tuber yield is contributed by environment. The AMMI analysis for marketable tuber yield (t/ha) indicated that IPCA1, IPCA2 and IPCA3 were highly significant (p<0.01) while IPCA4 showed non-significant interaction. The first and second principal component axis captured 40.37% and 30.8% of the GEI sum of squares in marketable tuber yield. Genotype 394640-539 gave high mean marketable tuber yield that is the most stable across environments. It was, thus, selected and recommended for wide production across locations.

English

This study was carried out in two locations in south eastern Nigeria in the year 2008 and 2009, to evaluate growth and yield responses of cocoyam cultivars to rates of NPK 15:15:15 fertilizer. This was aimed at identifying high yielding cocoyam cultivars and optimum rates of the fertilizer for optimum cocoyam production. Two locations: Nsukka (Enugu state) and Umudike (Abia state) were used for this study. The experiment was done in Nsukka location in 2008 and repeated in Umudike in 2009. Five Colocasiaesculenta cultivars (Cocoindia, Nworoko, Odogolo, Nadu and Nkpong) and five rates of NPK 15:15:15 (100, 150, 200, 250 and 300 kg/ha) were tested. The result showed that application of NPK 15:15:15 fertilizer increased growth in cocoyam. However, the highest tuber yield/ha of 37.85 tons/ha at Nsukka and 20.845 tons/ha at Umudike were realized in response to the application of 200 and 250 kg/ha, respectively. Further increases above these rates in the locations caused non-significant decline in tuber yield. The Cocoindia cultivar also produced the highest tuber yield/ha among the five cultivars in both Nsukka (30.10 tons/ha) and Umudike (19.068 tons/ha). It was also observed that higher tuber yield was obtained in Nsukka location than in Umudike location. This study has shown that the application of NPK 15:15:15 fertilizer increased tuber yield in cocoyam grown in the south eastern Nigeria. Key words: Colocasia esculenta, cultivars, fertilizer and tuber yield.

Water use efficiency of potato (Solanum tuberosum L.) under different irrigation methods and potassium fertilizer rates

This study was conducted to determine the effect of different irrigation methods and potassium fertilizers on potato yield in the Abu–Graib–Baghdad, Iraq Region, during season 2011–2012. Potato was grown under furrow and drip irrigation methods and three potassium fertilizers rates applied with 0.0, 300 and 600kg K2SO4ha−1. The obtained results indicated that, actual potato evapotranspiration ranged from 357.3 to 511.4mm in the growth season for all treatments. Furrow and drip irrigation methods had no significant effect on tuber yield under the experiential conditions. Potassium fertilizer influenced the tuber yield (P<0.05), and the highest tuber yield was registered for 600kg K2SO4ha−1, reaching 35.23Tha−1and 36.65Tha−1for furrow and drip irrigation, respectively. Water use efficiency increased from 5.129 to 7.379kgm−3 for furrow-irrigated treatments, and from 6.907 to 10.257kgm−3 for drip-irrigated treatments using the above mentioned rate of K-fertilizer.