Research Article

Citrus rootstock characterization against citrus canker and evaluation of antibiotics effect against Xanthomonas axonopodis pv. citri

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Citrus canker (X. axonopodis pv. citri) widespread bacterial disease which limits citrus productivity and causes quality deterioration. Citrus canker is mostly a leaf-spotting and fruit rind-blemishing disease, but under highly favorable conditions, infections cause defoliation, shoot dieback, and fruit drop. Citrus rootstocks exert a high degree of influence to scions in fruit production and plant susceptibility to diseases including citrus canker. Keeping in view the importance of citrus rootstock present study was planned to evaluate the performance of citrus rootstocks against citrus canker and antibiotics response to control X. axonopodis pv. citri. Eleven exotic citrus rootstocks were selected to evaluate against canker which was inoculated by grafting. Disease index was observed after 9 months of inoculation. Five different commercially available antibiotics were selected for the Invitro treatment, applied at 300, 400 and 500ppm. Inhibition zone was observed at four time points (24, 48, 72 and 96 hours). Kirumakki showed maximum resistance followed by Rangpur Poona nucellar and X639 while Rough lemon was highly susceptible. In Invitro evaluation maximum inhibition zone was expressed by Kanamycin sulphate at 500 ppm followed by Streptomycin sulphate. Lincomycin showed minimum inhibition zone as compared with control (Distilled water, No inhibition). Biochemical analysis exhibited that the disease index (%) decrease with increase of total phenolics contents and total protein contents. Whereas disease index had increasing trend with TSS. This study concludes that according to rootstocks evaluation Kirumakki and Rangpur Poona nucellar showed resistant performance while, on other hand Kanamycin Sulphate having maximum inhabitation against canker.


Genetic variability and association analysis for yield and yield related traits in finger millet (Eluesine coracana (L.) Gaertn)

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Finger millet (Eleusine coracana (L.) Gaertn) is regarded as cereal of hope because of its role in subsistence agriculture, and source of food for millions of poor people in Africa alone. Knowledge of the nature and magnitude of variation existing in breeding materials, interrelationships between quantitatively inherited plant traits is great importance for effective breeding. Forty nine finger millet  genotypes were tested at single location at Womberma, West Gojam Zone with the objectives of estimating the genetic variability, association among characters, and to estimate genetic divergence among the genotypes and clustering them in divergent groups. The experiment was conducted using simple lattice design with two replications. Results showed that genotypes had high values of genotypic and phenotypic coefficient of variation for effective tiller per plant, fingers per head, grain yield, biomass yield, lodging and blast severity. High heritability estimated was obtained for all of the traits ranged from 71.43 to 99.56%. Cluster analysis revealed that the 49 genotypes were grouped into nine clusters. Maximum and minimum intra and inter cluster distances was 6.12-16.33 and 17.08- 226.28 respectively. Principal component analysis indicated that three principal components explained about 68.07% of the total variation. Differentiation of the genotypes into different cluster was because of accumulative effect of a number of characters rather than small contribution of each individual character.


Grain yield response of maize (Zea mays L.) to variable rates of compost and nitrogen fertilizer integrations

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Declining soil fertility is one of the major factor limiting crop productivity in Ethiopia. This experiment was therefore, conducted to evaluate grain yield response of maize to variable rates of compost and urea fertilizer integration. The experiment was arranged in factorial combination of three level of compost (0, 5 and 10 t ha-1) and three levels of mineral N fertilizer in the form of urea (0, 92 and 105 Kg ha-1). The experiment was laid out in randomized complete block design with three replications at the experimental field of Hawassa University, Southern Ethiopia. The result revealed significant difference among compost levels for all of the traits studied. There is significant difference among nitrogen levels for grain yield, number of kernel per row, number of kernel per ear and hundred grins weight. Significant difference among treatments (combination of compost level and nitrogen level) were observed for grain yield, number of rows per ear, number of kernel per row, number of kernel per ear and hundred kernel weights. The combination of compost and urea at the rate of 10 t ha-1 and 105 kg ha-1, respectively, produced the highest kernel yield (11.3 t ha-1) followed by (10 t ha-1 and 92 kg ha-1) and (5 t ha-1 and 105 kg ha-1) with compost and urea combination 9.4 and 8.3 t ha-1 grain yield respectively. Generally, the combination of 10 t ha-1 compost with urea at the rate of 105 kg ha-1 resulted with 63% yield advantage compared with the control plot. It is therefore; wise to recommend 10 t ha-1 compost combinations with 105 kg of urea for improved maize yield for the farmers in the research area and areas with similar agro-ecology and resources availability.


Large scale evaluation of the improved tef (Eragrostis tef) technologies

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Tef is the most important staple crop in Ethiopia. Despite its importance and increasing demand in local and global markets, tef production and productivity have remained low. Therefore this experiment was implemented to assess farmer technology preferences and to create wider demand for the availability of high yielding improved tef varieties. The improved variety of Kora with its associated recommended management practices was used and compared with the local tef growing practice in the 2019 growing season on 65 farmers’ farm lands. All the necessary data were collected and estimated using descriptive statistics. The result showed that the variety of Kora provided a higher average grain yield of 2682.4 kg ha-1 and resulted in a yield advantage of approximately 76.9% higher grain yield over the local variety under farmer’s practices. The result further showed that in the study areas a higher technological index of 41.6% was recorded. Participant farmers were agreed that the variety Kora had longer panicle length, resistance to lodging, resistance to waterlogging, longer in plant height, higher in grain, and straw yield compared to their local variety and even the previously introduced varieties. The improved variety drew a lot of attention from farmers because of its high yielding potential, white seed colour, good straw yield, and lodging resistance. The result indicated that promoting the improved tef Kora variety at a large scale, along with the recommended management practices, could increase farmers' access to improved variety seed and extension services.


Genetic divergence of lowland rice (Oryza sativa L.) genotypes in Uganda

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Zelalem Zewdu

Published on: 30 Jun 2021 | DOI: https://doi.org/10.37446/jinagri/rsa/8.2.2021.34-38 | Pages: 34-38

Forty-eight lowland rice genotypes with two checks were evaluated for their agronomic performance, genetic variability, heritability, and genetic advance for yield and yield contributing traits. Among the tested genotypes SR33859-HB3324-133 (45.7 qha-1), SR33859-HB3324-93 (40.2 qha-1) were the high yielding genotypes above the better check. The analysis of variance showed significant differences for all measured traits and indicating the presence of high genetic variability among genotypes. A highly significant (P≤0.001) correlations were observed between flag leaf length and plant height (rp= 0.76, rg=0.84), panicle length and plant height (rp= 0.77, rg= 0.90), and panicle length and flag leaf length (rp= 0.75, rg=0.89). The estimates of GCV were lower than the respective PCV for all traits, indicating the influence of environmental factors on the expression of the traits. Characters like grain yield (94 %, 90.9), flag leaf length (97 %, 71.6), number of tillers per hill (91 %, 67.2) and plant height (99.0 %, 50.7) showed high heritability coupled with moderate genetic advance as percent of the mean, which suggesting that these traits are controlled by the additive type of gene action and selection could be possible for the improvement of these characters. On the other hand, moderate heritability estimates with low genetic advance as percent of the mean were recorded for flag leaf width and number of days to maturity indicated the presence of non-additive gene effects, and selection for these traits would be poor. As a result, the variability that exists in the germplasm provides an opportunity to use these genotypes in the genetic improvement program.


Genotype × Environment interaction studies in lentil under Afghanistan environments

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Lentil (Lens culinaris Medik. culinaris) is an important pulse crop causative to nutrition and food security of people in Afghanistan. Genotype by environment interaction (GEI) is one of the major factors restraining the efficiency of any breeding program. This study consisted of two lentil yield trials conducted in alpha design with two or three replicates at three locations for two years (2014-2015 and 2015-2016). Genotypic differences were significant (P<0.05) in all the environments. Genotype × location interactions were found significant (P<0.01) in each year for LIEN-LS and LIEN-SS trials. There were significant genotype × year interactions of crossover type. For LIEN-LS genetic materials, Herat and Mazar formed a mega-environment based on responses in 2015 and 2016. High yielding genotypes with specific adaptation to Mazar and Herat environment were LG16 (FLIP2012-21L) in 2015 and LG24 (FLIP2013-3L) in 2016, whereas LG30 (FLIP2013-20L) was identified as high yielding with specific adaptation to Nangarhar environment during both the years. The high yielding genotypes in 2015 were LG32 (FLIP2013-29L) at Herat, LG16 (FLIP2012-21L) at Mazar and LG30 (FLIP2013-20L) at Nangarhar from LIEN-LS. In 2016, LG12 (FLIP2013-16L) at Herat, LG5 (FLIP2013-3L) at Mazar and LG1 (FLIP2013-20L) at Nangarhar were identified as high yielding genotypes. In 2015-16, SG12 (FLIP 2013-51L) at Herat, SG2 (FLIP2013-59L) at Mazar and SG6 (FLIP2013-66L) at Nangarhar were the top yielding genotypes from LIEN-SS. The identified genotypes from LIEN-LS and LIEN-SS at the two locations (Mazar and Nangarhar) may be used for up-scaling lentil production to support food security in Afghanistan as well as for generating new genotypes using crossing-selection-evaluation cycle.


Identification of factors that influence farmers’ buying behavior towards tomato seed through factor analysis: a case study in Chittoor District of Andhra Pradesh

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Considering the increasing market space among the all vegetable crops and its profitability nature, farmers used to cultivate tomato crop in their major portion of their available land when comparison to other crops. The study was undertaken in Chittoor district to identify the reasons for farmers to buy specific seed or brand of tomato crop.  Through factor analysis, it was found that the majority of farmers consider the buying factors is the product value factor with highest mean score (3.89), second factor is product image with mean score (3.83) followed by product convenience with mean score of  (3.81), social influence and experiences (3.50). While location and accessibility (3.29) of seed availability, it was also noticed that, after using the brand and once he satisfied from specific brand, farmer will purchase the same brand repeatedly over the years even though its cost is high, anticipating that good returns will cover the cost of cultivation


Genotype x environment interaction and stability of drought tolerant durum wheat

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Genotype x environment interaction is of great interest for selecting cultivars for variable environment. The objectives were to evaluate presence of genotype by environment interactions and identify stable genotypes using different stability parameters. Twenty five selected durum wheat genotypes grown in randomized complete block design with three replications over six environments in main rainy season. The combined analysis of variance indicated that highly significant variations among genotypes, environments and their interactions on grain yield. The largest variation was accounted by environments, followed by GEI and then genotypes. The stability analysis using parametric measures identified G-24 as the most stable genotype followed by G-23 with above average grain yield. Stability parameters showed similar rankings of genotypes with different magnitudes and identified Genotypes 1, 24, 4, 10 and 17 as the most stable genotypes. As per the AMMI analysis the first two IPCAs showed significant variations and explained about 61% of GEI. GGE biplot categorized the environments in to two mega environments where Akaki and Gimbichu grouped together and that of Debre-Zeit light and black soil and Alemtena in the second mega environment and Minjar remained alone


Distribution and population dynamics of Coccinellidae predators associated with white mango scale, Aulacaspis tubercularis (Newstead) in southwest Ethiopia

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The survey was conducted in Southwestern Ethiopia, to study the distribution and population dynamics of Coccinellidae predators associated with White Mango Scale (WMS). The identification of the predators was done by collecting infested mango leaves from the targeted fields. In all surveyed areas, three Chilocorus beetles spp. (Chilocorus spp. 1, 2, and 3) and one unknown beetle were identified feeding on all stages of WMS. The number of Chilocorus spp. 1 was higher compared with the other identified predators in all surveyed areas. Among the surveyed areas, East Wollega had the highest population of Chilocorus spp. 1. The peak population of the identified Coccinellidae predators and WMS varied from March to May depend on the species and areas. Overall, during the rainy and high temperature seasons, the number of both WMS and predators declined. The correlation study showed that the populations of the predators were positively correlated with weather factors and WMS, as prey factor.  Altogether, the current study suggests that identified Coccinellidae Chilocorus spp. 1 was considered as the potential predator to control WMS. Therefore, future studies need to be focus on predacious efficacy, mass rearing and field release mechanism and compatibility with other management options


Genetic analysis and genotype x environment interaction for resistance to northern leaf blight disease in tropical maize (Zea mays L.) genotypes

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Akinlolu Ohunakin

Published on: 30 Jun 2021 | DOI: https://doi.org/10.37446/jinagri/rsa/8.2.2021.67-74 | Pages: 67-74

Northern leaf blight (NLB) disease one of the most devastating foliar diseases of maize accounting for more than 50% yield losses annually. Information on inheritance of NLB resistance of maize population adaptable to tropical environments is required. Thus, hybrids generated through 10 x 10 half-diallel of tropical maize inbred lines were evaluated in five environments to determine their combining ability, impact of NLB disease on grain yield, and genotype x environment (G x E). The 45 single cross F1 hybrids and nine hybrid checks were evaluated across five environments using 9 x 6 alpha lattice with three replications. The greater proportion of general combining ability (GCA) over specific combining ability (SCA) effects across environments implies that additive gene action influences the inheritance of these traits. Predominance of additive gene indicates that rapid progress would be achieved from selection for NLB disease resistance. Regression analysis revealed 1030–1130 kg ha-1 reduction in maize grain yield per increase in NLB severity score. Significant negative relationships (r = -0.33 to -0.77) were reported between grain yield and NLB severity scores in this study. This showed the potential of NLB to cause yield reduction in susceptible genotypes. GGE revealed that the test environments fell into two sectors, indicating the existence of two mega-environments and presence of significant crossover interaction



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