Open Access Short Research Article

Statistical Analysis for Correlated Paired-plot Designs

Dilermando Perecin, Guilherme Moraes Ferraudo, Carlos Alberto Mathias Azania, Ana Regina Schiavetto

Journal of Experimental Agriculture International, Page 1-7
DOI: 10.9734/AJEA/2015/20722

This work is aimed to evaluate different statistical analysis with a randomized complete block design for paired-plot studies of herbicide selectivity in sugarcane experiments. Two  procedures were considered: i) the construction of a t-test to assess the hypothesis of the paired-plot mean  difference to be zero in each treatment; or ii) the use  of an analysis of variance where the treated and paired  plots were considered in a split-plot model and the interaction is sliced  by treatment. By simulation with normal  bivariate  distributions, with  uniform (zero, 0.11, 0.33, 0.44, 0.67 or 0.89)  or heterogeneous correlations, the two procedures showed similar performance. The power of the tests increases as the correlation of paired-plot increases.

Open Access Original Research Article

Photosynthetic Efficiency and Antioxidant Activity of Cotton under Drought Stress during Early Floral Bud Development

Cristiane Pilon, Derrick M. Oosterhuis, Glen L. Ritchie, Eliege A. Paiva

Journal of Experimental Agriculture International, Page 1-13
DOI: 10.9734/AJEA/2015/21477

Aims: Identify changes in photosynthetic efficiency, pigment concentration, and enzyme activity in cotton caused by water-deficit stresses during early floral bud development; compare physiological stress responses among cotton cultivars.

Study Design: A strip plot design with two water regimes at Lubbock, and a strip split plot design with two water regimes and three cultivars at Marianna, with five replications.

Place and Duration of Study: Fields at Quaker Avenue Research Farm of Texas Tech University in Lubbock, TX in 2012 and at the Lon Mann Cotton Research Station of University of Arkansas in Marianna, AR in 2013.

Methodology: Water was withheld for 14 days from the water-deficit stress treatment at the appearance of floral buds on the cotton plants. Stomatal conductance and chlorophyll a fluorescence were measured In situ seven and fourteen days after the onset of stress; tissue samples were also collected and analyzed for enzyme activity and pigment concentration.

Results: Lower stomatal conductance was observed in plants under water-deficit stress in all instances. Actual quantum yield of photosystem II (ФPSII) varied among the cultivars, with DP 0912 having the highest ФPSII, followed by ST 5288 and PHY 499. The ФPSII and electron transport rate also decreased over time. Pigment concentrations, including Chlorophyll a and b, were reduced by water-deficit stress over time among all cultivars and sampling dates, with the lowest pigment concentrations occurring in DP 0912. Enzyme activity was significantly increased by water-deficit stress, with stressed plants having a 4-fold increase in superoxide dismutase activity, a 10-fold increase in catalase activity, and a 57% increase in ascorbate peroxidase concentration compared with the control.

Conclusion: Stomatal conductance and pigment concentration were sensitive to water-deficit stress at squaring development; however, chlorophyll a fluorescence was not responsive to the stress. Increased antioxidant activity appeared to be associated with scavenging of free radicals in cotton. ST 5288 and PHY 499 seemed to have improved tolerance to water-deficit conditions compared to DP 0912. However, further research is needed to identify traits related to drought tolerance of these cultivars.

Open Access Original Research Article

Product Quality Assessment of Clarias gariepinus Fed on Varying Dietary Levels of Azadirachta indica Leaf Meal

D. C. Anyanwu, J. I. Offor, U. U. Nkulo

Journal of Experimental Agriculture International, Page 1-6
DOI: 10.9734/AJEA/2015/19405

This feeding trial was conducted to assess the body composition and product quality of Clarias gariepinus fed dietary levels of Azadirachta Indica leaf meal (AILM). Four isonitrogenous diets of 36% crude protein were formulated containing 0, 5, 10 and 15% AILM (Diets 1-4). The diet containing 0% leaf meal (Diet 1) served as the control. Each dietary treatment was tested in triplicate group of 15 fingerlings per aquarium. Samples from each treatment were analyzed bi-weekly to evaluate their carcass composition, and data subjected to a one way analysis of variance (ANOVA), while organoleptic assessment was carried out at the end of the experiment to determine the end product quality. The results for carcass composition show that fish fed on diets 3 and 4 (10% and 15% AILM respectively) were significantly (P<0.05) higher in crude protein but were significantly (P<0.05) poorer in moisture content. Crude fibre was significantly (P<0.05) highest for fish fed on diet 4. Fish on all dietary treatments were of good quality as shown in their mean scores both of fresh and cooked samples. Fish on diet 1 (0% AILM) dietary treatment were however significantly (P<0.05) superior to fish on other dietary treatments both for fresh and cooked samples. The present study shows that Azadirachta indica leal meal as feed ingredient in the diets of Clarias gariepinus, had no deteriorating effect on carcass composition and product quality of the fish.

Open Access Original Research Article

Intergenerational Transfers of Managerial Control in U.S. Family Farm Businesses

K. Y. Lange, J. W. Johnson, P. N. Johnson, D. Hudson, C. Wang, A. W. Gustafson

Journal of Experimental Agriculture International, Page 1-12
DOI: 10.9734/AJEA/2015/20808

Aims: Sustaining a family farm business for multiple generations is a great concern for many farm families. The transfer of managerial control in family farm businesses often takes place separately from the transfer of farm ownership. This article identifies variables affecting the transfer of managerial control of family farms and determines the impact of these variables on the transfer decision.

Study Design: An intergenerational transfer model integrating both altruistic motivation and exchange motivation for family farm management intergenerational transfers is used to examine the motivations impacting the decision for a designated farm successor to participate in the management activities of a family farm business.

Methodology: A national farm-level dataset, the Agricultural Resource Management Survey (ARMS), was utilized. The total number of respondents who stated that a successor had been selected was 4090. Of those respondents who indicated that a successor had been selected, 750 specified that the successor participated in the management activities of the business. A binary logit model was estimated in order to examine the decision for a designated successor to participate in the management activities of the farm business.

Results: Results indicate that operator demographics, business planning practices, value of farm assets and inputs, and non-farm assets significantly impact the decision to transfer managerial control to a designated successor.

Conclusion: Business planning professionals and financial advisors must be aware of factors impacting farmer decisions to transfer farm businesses and subsequent management responsibilities to successors. Results presented will allow these consultants to better educate farm operators during the transfer planning process, thus improving the succession decisions that farm families make, and ultimately enhancing the opportunity for successful farm transfer

Open Access Original Research Article

Phenotypic Diversity of Selected Dual Purpose Forage and Grain Sorghum Genotypes

S. Chikuta, T. Odong, F. Kabi, P. Rubaihayo

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/AJEA/2015/20577

Aims: To study the phenotypic diversity of 25 forage and 45 grain sorghum genotypes for dual purpose as food and feed and to identify traits that might contribute to genetic improvement.

Study Design: A 7 × 10 alpha lattice design was used with two replications at two sites.

Place and Duration of Study: The study was conducted at Makerere University Agricultural Research Institute Kabanyolo (MUARIK) and National Semi Arid Resources Research Institute (NaSARRI) in Uganda between September to December, 2013 (Season 1) and April to July 2014 (season 2).

Methodology: Morphological and agronomic data were taken for each genotype from each environment in the two seasons and subjected to combined analysis of variance separately for the grain and forage sorghums. Multivariate analysis was done based on principle component and cluster analyses in which grain and forage sorghum genotypes were combined.

Results: Analysis of variance revealed significant differences (P < 0.001) among the genotypes for biomass, grain yield, plant height and days to flowering indicating the possibilities of improving these characters through phenotypic selection. Cluster analysis grouped the genotypes into 3 clusters with cluster 1 retaining majority of the forage genotypes characterised with high biomass, Cluster 2 containing a mixture of the forage and grain sorghums characterised with high grain yield while cluster 3 contained only the grain sorghums. The first four principle components explained 89% of the total variations observed in the genotypes.

Conclusion: Based on the performance of genotypes in this study, simultaneous selection of genotypes exhibiting moderate to high levels of grain and fodder traits resulted in twelve genotypes being selected as parents for the development of dual purpose sorghum cultivars.

Open Access Original Research Article

Cost Efficiency of NERICA Producing Households in Ghana: A Modified Non-neutral Stochastic Frontier Analysis

S. Amewu, E. E. Onumah

Journal of Experimental Agriculture International, Page 1-13
DOI: 10.9734/AJEA/2015/19866

Aim: To investigate cost efficiency and its determinants on New Rice for Africa (NERICA) farms in Ghana whilst accounting for the non-usage of fertilizer and herbicides by some farmers.

Study Design: Cross sectional.

Place and Duration of Study: Kpando, Hohoe and Kadjebi Districts in the Volta Region of Ghana in the 2010/2011 cropping season.

Methodology: Single-stage maximum likelihood estimation of a modified Cobb-Douglas stochastic cost frontier and inefficiency model. The inefficiency model is extended to also account for the interactive effect of some farm specific factors on efficiency and uses a cross-sectional data on 159 farm households.

Results: The results reveal that the cost function monotonically increases in all the input prices and output. The scale economies analysis indicates that economies of scale prevail in the production of NERICA rice in the study area. The combined effects of farm specific factors and some interactions were found to have significant influence on cost efficiency. Estimated mean cost efficiency is 107% indicating that on average NERICA farmers incur costs about 7% above the minimum obtainable cost. Level of education is found to improve cost efficiency.

Conclusion: On the average NERICA farmers are fairly cost efficient and expanding their current scale of production will result in a decrease in per unit cost of output. Education programs designed for uneducated farmers should be introduced. The youth who are more educated should be encouraged to venture into NERICA farming. Farmers in remote districts should be provided with agricultural information and also given ready access to inputs such as fertilizer and seed.

Open Access Original Research Article

Morphological Characters of Guava landraces in Western and Coastal Kenya

Liharaka Mercy Kidaha, Amos Emitati Alakonya, Aggrey Benard Nyende

Journal of Experimental Agriculture International, Page 1-11
DOI: 10.9734/AJEA/2015/12674

Morphological characterization of guava landraces from Western and Coastal landraces was done using 13 qualitative and 2 quantitative descriptors. Root descriptors between the landraces in the two regions did not show differences while the leaf, fruit, branching of stem showed variations. Leaf shape varied, being oblong, trapezoidal, elliptical and ovate. Branching habits were either axial,erect or irregular. Ripe fruit color varied from pink to cream. Grouping of characters using unweighed neighbour joining (Darwin software) resulted to three clusters. The clusters had landraces within the region and others clustered across the region. The results revealed that Kenyan landraces varied morphologically within and across regions.

Open Access Original Research Article

Effect of Varying Levels of Probiotic on the Performance of Broiler Chicks

Muhammad Sheraz Nawaz, Muhammad Sharif, Fawwad Ahmad, Muhammad Yousaf, Zafar Alam

Journal of Experimental Agriculture International, Page 1-6
DOI: 10.9734/AJEA/2015/19308

The experiment was conducted to investigate the effect of varying levels of probiotic (Toyocerin®) on the performance of broiler chicks in a completely randomized design. One hundred and fifty broiler chicks were divided into five experimental groups (three replicates of ten chicks each). Broiler chicks were raised for 42 days. Five isocaloric and isonitrogenous broiler starter and finisher diets were formulated. Toyocerin® was added at the level of 0, 25, 50, 75 and 100 g/100 Kg of diet and denoted as T1, T2, T3, T4 and T5 respectively. Whereas, T1 was treated as a control group. Weekly body weight gain, feed consumption and feed conversion ratio were recorded. At the end of trial, two birds per replicate were slaughtered randomly for the determination of carcass traits. The addition of Toyocerin® in the diet of broilers (8-42 day) significantly improved the body weight gain, feed intake, feed conversion ratio, dressing percentage, breast meat yield and liver weight as compared to control group. The findings revealed that addition of Toyocerin® improved birds’ performance and carcass traits