Open Access Method Article

Coring Method of Sampling Potato Tubers to Detect Ralstonia solanacearum

Lilian A. Okiro, Steven G. Nyanjom, Monica L. Parker

Journal of Experimental Agriculture International, Page 1-6
DOI: 10.9734/JEAI/2016/28550

Bacterial wilt caused by Ralstonia solanacearum is considered among the most damaging diseases of potato in Sub-Saharan Africa. In Kenya, majority of farmers visually select and save seed from harvested potato tubers and reuse the same tubers for several seasons. Latently infected seed tubers which cannot be identified by visual inspection during certification further compounds the situation compelling the need for laboratory testing. The study evaluated the effectiveness of coring tuber samples to improve sampling efficiency for onward laboratory diagnosis. In this study, the coring method of sampling potato tubers for detection R. solanacearum was evaluated. Coring involves taking multiple tuber samples direct from the stolon attachment site into a collection tube containing extraction buffer that provides the extract for further diagnostic tests. Coring was assessed using field samples from different potato growing regions of Kenya including, Koibatek, Molo, Uasin Gishu, Bungoma and Kisii and tested using Nitrocellulose Membrane (NCM) ELISA. These results were compared to PCR, qPCR and LAMP. Coring method was statistically reliable (p>0.05) when compared to the standard sampling method used in Kenya to detect R. solanacearum. The coring of potato tubers is a reliable and quicker method of sampling that reduces the turnaround time of testing hence improving efficiency.

Open Access Short Research Article

Characterization of the Water Economy of Sugarcane Transgenic Genotypes

C. J. Fernandez, E. Mirkov, M. B. Dickman, M. D. Molina-Risco, J. C. Correa, W. J. Grichar

Journal of Experimental Agriculture International, Page 1-13
DOI: 10.9734/JEAI/2016/29099

Aims: Study designed to characterize water economy of a group of sugarcane transgenic lines grown in a rain-sheltered, well-watered, and water-stressed conditions.                

Study Design: Randomized complete block with 3 replications.                                     

Place and Duration of Study: The study was conducted at the Texas A&M AgriLife Research and Extension Center in Corpus Christi during 2012 and early 2013.                       

Methodology: Stem cuts of 14 transgenic lines and two non-transgenic background genotypes (NTBGs) were hand-planted in 13.5-L pots. The study had two phases. In the 1st phase, lines were subjected to a well-watered regime of 1.3 L d-1. In the 2nd phase, lines were exposed to water deficits by reducing irrigation to 0.65 L every other day. At the end of both phases, plants were harvested to determine biomass and leaf area.                   

Results: Under well-watered conditions the higher nominal water use efficiency (NWUE) attained by lines 15 and 133 over the NTBG was related to their higher production of biomass, which was not paralleled by an increase in whole-plant transpiration. Lines 132 and 20, which showed NWUE not different than their NTBG, exhibited lower and higher cumulative whole-plant transpirations, respectively. Under water stress, lines 11 and 163 had lower NWUE than their respective NTBGs, as a result of lower biomass production not paralleled by a lower whole-plant transpiration. Lines 132 and 112 had NWUE not different than the respective NTBGs, but they both exhibited lower cumulative whole-plant transpiration and lower biomass production.

Conclusion: The study helped characterize the water economy of 14 transgenic sugarcane lines. Under well-watered conditions, lines 15 and 133 exhibited higher NWUE, line 132 was more water-conservative, and line 20 was more water-prodigal than the NTBG. Under water stress, lines 11 and 163 had lower NWUE and lines 132 and 112 were less tolerant to water stress than their respective NTBGs.

Open Access Short Research Article

Hybrid Vigor Expression for Some Important Agronomic Traits in Rice Using Diallel Method

G. B. Anis, H. F. El-Mowafi, A. EL-Sabagh, C. Barutçular

Journal of Experimental Agriculture International, Page 1-6
DOI: 10.9734/JEAI/2016/29742

Hybrid vigor expression in rice was studied for some agronomic traits in 15 hybrids involving six parents using half diallel mating design. Analysis of variance showed significant differences in parent's vs crosses for all studied traits. The high manifestation of heterosis for grain yield per plant is evident by significant superiority of hybrids over mid parent was ranging from 16.37 to 65.35% in most of hybrid combinations. The high better parent heterosis (heterobeltiosis) for yield per plant was observed in the cross Giza 177 x Chinese2 with value of 63.09%. Similarly, the cross Chinese 2 x GZ 8479-6-2-3-1 showed superiority over mid-parent heterosis with 65.35% for grain yield and also showed significant heterosis for some traits. The development of pure lines from segregating population is very important for evolving high yielding varieties. The crosses exhibiting good heterotic expression in F1 are likely to give better segregants in later generations were additive gene effects were high.

Open Access Original Research Article

Effect of Tillage Practice on Growth and Yield of Three Selected Cowpea Varieties

R. N. Khaemba, J. M. Kinama, G. N. Chemining’wa

Journal of Experimental Agriculture International, Page 1-11
DOI: 10.9734/JEAI/2016/26894

Aim: To evaluate the influence of tillage practice on growth and yield performance of three cowpea varieties.

Study Design: The treatments were laid out in a randomized complete block design with a factorial arrangement and replicated three times.

Place and Duration of Study: Study was carried out at St. Theresa demo farm and Nakamane irrigation scheme in Turkana county between November 2014 and January 2015.

Methodology: Treatments comprised three tillage practices: conventional tillage (control), conventional tillage + mulch and zero tillage and three cowpea varieties: M66, K80 and Kenkunde. Data collected included: Plant height, nodule count, total leaf vegetable yield, pod length, number of pods per plant, number of seeds per pod, grain yield,100 seed weight, total biomass and harvest index.

Results: Tillage practice and variety had no effect on plant height. Conventional tillage+ mulch increased the number of nodules per plant by 42.98%, while zero tillage reduced it by 27%. Conventional tillage + mulch increased fresh leaf weight, total grain yield, total biomass and harvest index.  Tillage practice and variety had no significant influence on 100 seed weight at St Theresa demo farm. However, at Nakamane irrigation scheme, tillage+mulch increased 100 seed weight by 12.6% while zero tillage reduced it by 7.2%. Nodule count and pod length were different among varieties; however, the effect of variety on the number of pods per plant, total biomass and harvest index were not significant. Variety had significant effect on total grain weight at St Theresa demo farm Kenkunde out yielded K80 and M66 by 10.1% and 16.9% respectfully.

Conclusion: Conventional tillage + mulch significantly outperformed conventional tillage and zero tillage in growth, nodule number, total biomass, grain yield and yield components. Zero tillage produced higher grain yield and harvest index than conventional tillage. Based on these results generally, Kenkunde variety was superior to the other two varieties in nodulation, fresh leaf weight and grain yield. The effects of variety   on biomass and harvest indices were not significant implying little genetic variability among varieties on these yield attributes.

Further work is required on the effect of tillage practice on soil moisture retention in Turkana County.

Open Access Original Research Article

Growth and Dry Matter Partitioning of Common Bean (Phaseolus vulgaris L.) Genotypes as Influenced by Aluminum Toxicity

Hirpa Legesse, Robi Nigussie-Dechassa, Setegn Gebeyehu, Geremew Bultosa, Firew Mekbib

Journal of Experimental Agriculture International, Page 1-13
DOI: 10.9734/JEAI/2016/4049

Aims: This study was conducted to assess effects of different exchangeable aluminium concentrations on growth and dry matter partitioning of two common bean genotypes (new BILFA 58 and Roba 1) grown on lime-treated and lime-untreated acid soils.

Study Design: Factorial combinations of five rates of aluminium (0.0, 12.5, 25.0, 50.0, and 100.0 mg Al kg-1 soil) and two genotypes were laid out in a completely randomized design of three replications.

Place and Duration of Study: The experiment was conducted in the vegetation hall of Nekemte Soil Laboratory, western Ethiopia from July to October, 2011.

Methodology: For each treatment, four plants were raised per pot, data related to growth and dry matter partitioning of the crop were collected at 25 and 35 days after seedling emergence (DAE).

Results: Aluminium rate and genotype interaction had significantly (P=0.01) affected all parameters considered except relative growth rate and shoot to root weight ratio for lime-untreated soil, and specific leaf area, leaf fraction and leaf area for lime-treated soil. A significant growth reduction was found on lime-untreated soil than treated soil, particularly as aluminium applied increased. On average, application of aluminium led to 37.5, 32.9, and 35.7% reduction in absolute and relative growths, and net assimilation rates. The differences due to aluminium rate and genotype were also significant for dry matter partitioning and root to shoot ratio. On both lime-treated and untreated soils, dry matter partitioning to root was higher for new BILFA 58 than for Roba 1 at 25 and 35 DAE.

Conclusions: Application of aluminium had a significant adverse effect and decreased the growth of two genotypes under both lime-treated and untreated soils. However, growth reductions were lower on lime-treated soil than untreated soil and genotype new BILFA 58 had performed better than Roba 1 under increased soil acidity and aluminium concentration.  

Open Access Original Research Article

Determinants of Cashew Growers’ Participation in a Joint Contract Farming-and-processing Investment Project in Benin

B. G. Honfoga, J. Dossou, S. M. Agboton, H. Sommer

Journal of Experimental Agriculture International, Page 1-15
DOI: 10.9734/JEAI/2016/28918

Aims: This research aimed to identify the determinants of Village Cashew Growers Cooperatives (CVPA)’s participation in a joint cashew contract farming-and-processing investment project.

Study Design: The processing system includes village-level pre-processing satellite units which would supply unhusked kernels to a central unit in charge of the next stages of processing and marketing of white and roasted kernels. The study design includes (i) a profit sensitivity analysis based on cashew price simulation, and (ii) an elicitation of farmers’ opinions about the joint investment venture.

Place and Duration of Study: From September to December 2015, a survey was conducted in Glazoue and Dassa-Zoumè districts, the main cashew growing areas of Benin, where annual rainfall ranges from 960 – 1260 mm.

Methodology: Processing technology documentation and field observations were done for the profit sensitivity analysis, and questionnaire-based interviews and focus group discussions were conducted with 43 CVPA to assess growers’ willingness to participate in the project. Data on CVPA characteristics and their functioning were collected and a logistic regression model was run to identify the determinants of the joint venture investment.

Results: The study found that the price range of unhusked kernels for a profitable processing system was 1640-2493 FCFA/kg. The main determinants of CVPA participation in the investment included expected cashew producer price at 5% significance level, and sex of cooperative's chairman, expected commission and cashew assembly service income (rebate), and size of cooperative at 10% level. Expected price, expected rebate, sex of chairman and registration fostered participation, whereas size of cooperative and exit likelihood hampered participation.

Conclusion: The joint processing investment project can be successfully implemented with farmers’ participation, if cashew nut producer prices are attractive, and cooperative’s gender-wise leadership and contract farming management are improved. Producer price monitoring and promoting professional farmers’ business groups and innovative trade partnerships, with enhanced negotiation and investment capacities, will be key to increase farmers’ income and ensure poverty reduction in the cashew sub-sector in Benin.

Open Access Original Research Article

Influence of In-situ Soil Water Conservation Practices on Growth, Yield and Economics of Large Cardamom under Rainfed Condition at North East India

B. A. Gudade, Subhash Babu, A. B. Aage, S. S. Bora, K. Dhanapal, Sreekrishna Bhat, T. Bhutia, Raghavendra Singh

Journal of Experimental Agriculture International, Page 1-8
DOI: 10.9734/JEAI/2016/28710

Field experiment was carried out during 2015-2016 in rainfed condition at Indian Cardamom Research Institution (ICRI), Regional Research Station, Spices Board Research farm at Kabi, North Sikkim, India. The experiment was  laid out in a Randomized Block Design, with eight treatments viz., T1 (trench across the slope), T2 (trench across the slope + biomass in trench), T3 (pit in between four plants), T(pit in between four plants + biomass in the pit), T5 (half moon-shaped trench at the base of every clump), T6 (half moon-shaped trench + biomass in trench), T(surface mulching) and T(control) with three replications. In respect of growth parameters of large cardamom significantly higher number of immature tillers (5.63 & 5.62), mature tillers (5.40 & 5.42) and vegetative buds (5.59) were recorded in trenches across slope filled with biomass followed by treatment half-moon shape trench at base of every clump. Highest number of spike/clump (4.62), capsule/spike (8.34), dry yield/clump (57.92 gm), dry yield (257.42 kg/ha) yield parameters were found in the treatment having trench across slope filled with biomass, followed by treatment having half-moon shape trench at base of every clump as compare to control. Among the soil moisture conservation practices, surface mulching recorded significantly higher values of soil moisture i.e.23.15, 22.96, 24.26, 23.00 and 23.72 per cent on 30th November, 31st December, 31st January, 29th February and 31st March, respectively. The treatment trench across the slope+ biomass in slope gave maximum net ( 2, 81,009/-) and gross return ( 4, 11,099/-), as well as benefit: Cost ratio (2.16), followed by half-moon shape trench at base of every clump, when compared with the control.