Open Access Original Research Article

Development of In vitro Tetraploid Plants of Hevea brasiliensis

U. K. Divya, S. Sushama Kumari

International Journal of Plant & Soil Science, Page 1-12
DOI: 10.9734/ijpss/2019/v28i630125

Increase in global consumption of natural rubber necessitates crop improvement of Hevea aimed at increased productivity. As conventional breeding of Hevea is very elaborate and time consuming. Hence in the present study development of tetraploids through chromosome doubling of diploid callus obtained from cultured immature inflorescence of Hevea using colchicines were attempted. Chromosome doubling of the diploid callus occurred when treated with 1.25 µM colchicine for 3 days. In higher concentrations as well as at longer exposure periods, the callus texture and viability were affected. 48 % embryo induction and a maturation frequency of 45 % were obtained. Embryo germination and plant regeneration with a germination frequency (30 %) and a regeneration frequency (20 %) were obtained. Cytological and flow cytometric analyses confirmed the tetraploid nature of the colchicines treated callus. In vitro tetraploid plant developed through these in vitro techniques can be further used in Hevea brasiliensis breeding.

Open Access Original Research Article

Edaphic Factors and Flooding Periodicity Determining Forest Types in a Topographic Gradient in the Northern Brazilian Amazonia

L. A. Beltrán Alemán, R. I. Barbosa, I. Montero Fernández, L. C. S. Carvalho, P. E. Barni, R. L. C. Oliveira, J. F. Vale Jr., S. A. Saravia Maldonado, N. E. Arriaga Pérez

International Journal of Plant & Soil Science, Page 1-11
DOI: 10.9734/ijpss/2019/v28i630127

The Brazilian Amazonia is a region covered by an extensive mosaic of tropical forests conditioned by different topographical and hydro-edaphic features. Although studies relating environmental determinants of structure and floristic composition are systematically evolving in the region, there is no doubt that there are still information gaps due to the lack of research in peripheric areas of the Amazonia. The seasonally flooded areas of the state of Roraima situated on rio Branco-rio Negro basin, northern Brazilian Amazonia, still are deprived of such information. In this way, this work had as objective determine the physical and soil chemical attributes, and the flooding periodicity that characterize different forest types dispersed in a topographic gradient located in an area on the north of rio Branco-rio Negro basin. Soil samples (0-60 cm) were collected along a 2.7 km transect (31.1-64.8 m a.s.l.) crossing three different forest types: (i) mosaic between treed and forested shade-loving (La+Ld), (ii) area of ecological tension between forested shade-loving and open ombrophilous forest (LO) and (iii) open ombrophilous forest (Ab+As). The results indicated different soil classes and flooding periodicity for each forest type observed: Entisols Fluvents (La+Ld, 3-4 months flooded), Entisols Quartzipsamments (LO, 1-2 months) and Yellow Ultisols (Ab+As, no flooding). All analyzed soils were defined as nutrient-poor areas, especially those located on low altitude, characterized for higher hydrological restrictions (seasonal flooding) aggregating forest types of lower structural patterns (e.g. La+Ld). Soils on low altitude were also characterized as those with the highest percentage of fine sand and silt, while soil free of seasonal flooding (Yellow Ultisols) presented the highest levels of clay and coarse sand, always associated with the ombrophilous forests (higher structural patterns). These results improve our understanding of the environmental factors conditioning different forest types in this peripheral region of Amazonia, suggesting that ecosystems with higher hydro-edaphic restrictions are a strong indicator of forest types with lower structural patterns.

Open Access Original Research Article

Enhancing Micro-propagation of Some Cameroonian Plantain (Musa paradisiaca L) Cultivars/Landraces

Dominic, K. Njualem, Tange Denis Achiri, Amanwi Climson Yuninwenkeh, Abdulai Assan Nkuh, Fornkwa Victorine Yaya

International Journal of Plant & Soil Science, Page 1-10
DOI: 10.9734/ijpss/2019/v28i630128

Aims: This study was conducted to enhance germplasm conservation of some indigenous plantain landraces through tissue culture techniques in Cameroon.

Study Design: The experiment was laid out in a completely randomized design (CRD) with three treatments in four replications.

Place and Duration of Study: The study was conducted in the tissue culture laboratory of the Institute of Agricultural Research for Development (IRAD), Bambui, Cameroon, in the first half of 2018.

Methodology: Explants were gotten from three plantain land races (Kwah, Ngumbe and Sangmoh) gotten from Bambui. Shoot tips were excised and cultured on Murashige and Skoog (MS) medium supplemented with 30 g of sucrose, 5 ml of ascorbic acid, 4 ml of 6- benzylaminopurine (BAP 1 mg/l), 1 ml indole-3- acetic acid (IAA 1 mg/l) and 6 g of agar at pH of 5.8±0.1 for shoot initiation and proliferation. Data was collected over a period of 12 weeks every 4th week on the average number of buds, shoot length, number of leaves, number contaminated and number dead.

Results: All the landraces responded positively to shoot tip culture, since they could adapt and regenerate by producing buds with Ngumbe giving the highest mean number (7.0) of buds and Sangmoh giving the lowest (3.0). Analysis of variance revealed significant differences (p = 0.05) in most of the parameters measured except for number contaminated. High dead rate was recorded in Kwah with dead mean of 3.0. Ngumbe was found to regenerate better than Kwah and Sangmoh.

Conclusion: It is recommended that the three plantain landraces, germplasm be conserved. The ramification of this finding vis-à-vis germplasm conservation and increase productivity is explained.

Open Access Original Research Article

Estimation of Leaf Area by Linear Dimensions in Coffea dewevrei

Omar Schmildt, Enilton Nascimento de Santana, Vinicius de Souza Oliveira, Rafael Ruy Gouvea, Lucas Corrêa Souza, Alba Nise Merícia Rocha Santos, Sirlane Machado Silva, Karina Tiemi Hassuda dos Santos, Gleyce Pereira Santos, Cesar Jose Fanton, Sara Dousseau Arantes, Edilson Romais Schmildt

International Journal of Plant & Soil Science, Page 1-8
DOI: 10.9734/ijpss/2019/v28i630129

The objective of this research was to select the equation that best estimates the leaf area of the coffee tree Coffea dewevrei, from the linear dimensions of the leaves. For this purpose, 140 leaves of adult plants were collected from the Capixaba Institute for Research, Technical Assistance and Rural Extension, in the city of Linhares, North of the State of Espírito Santo, Brazil. The length (L), the width (W), the product of the multiplication between the length and width (LW) and the leaf area observed (OLA) were determined from all leaves. For the modeling, a 100 leaves sample was used, where OLA was used as a dependent variable in function of L, W and LW as independent variable, being obtained the following models: linear first degree, quadratic and power. For the validation, a sample of 40 leaves was used, where the values of L, W LW were substituted in the equations generated in the modeling, thus obtaining the estimated leaf area (ELA). A simple linear equation model was fitted for each modeling equation relating ELA in function of OLA. The hypotheses H0: β0 = 0 versus Ha: β0 ≠ 0 and H0: β1 = 1 versus Ha: β1 ≠ 1, were tested using Student's t test at 5% probability. The mean absolute error (MAE), root mean square error (RMSE) and Willmott's index d for all equations were also determined. The best model that estimates the area of Coffea dewevrei was chosen through the following criteria: β0 not different from zero, β1 not different from one, MAE and RMSE values closer to zero and index d closer to the unit. The area of the leaves can be determined by its greater width (W), through the quadratic model equation ELA=-10.255+1.020(W)+1.293(W)2.

Open Access Original Research Article

Insect Pest Profile of Leaf Amaranth (Amaranthus hybridus L) and Prevention Herbivory Using Oil-Based Extracts of Alium sativum L, Xylopia aethiopica Dunal and Eucalyptus globolus L

Borisade, O. A., Awodele, S. O., Uwaidem, Y. I.

International Journal of Plant & Soil Science, Page 1-9
DOI: 10.9734/ijpss/2019/v28i630130

Pest profile of Amaranthus hybridus was recorded in a single organic agro-ecosystem in Southwestern Nigeria between November-December in 2016 and January-February 2017, during the dry season. Activities of different pests were monitored to identify those responsible for the most significant damage. Vegetable oil-based extracts of Alium sativum, Xylopia aethiopica and Eucalyptus globolus were prepared and applied on A. hybridus as protectants against herbivory by phytophagous insects and damage to foliage was assessed. Thereafter, the extracts were rated based on the mean percentage damage (MPD) recorded in different plots in relation to the treatments. A total of nine pests were recorded from three insect Orders namely, Orthoptera (62.5%), Coleoptera (12.5%) and Lepidoptera (25%) and they were grouped into Major, Minor or Occasional pests based on their activities. Two lepidopterans, Spoladea recurvalis and Psara basalis (Family: Crambidae) were responsible for the most significant damage. All the extracts reduced damage with a statistically significant difference (P<0.05) compared with the control. The MPD in X. aethiopica-, A. sativum- and E. globolus-treated plots and the control plots were 10.9%, 8%, 14% and 31.2% respectively when the amaranth was due for harvest in the first trial. The MPD to the amaranth in the treated plots during the second trial was between 13.6% and 16.3% when the harvest was due while the MPD in the control was 54.9%. The performances of E. globolus and X. aethiopica were comparable and they were relatively more effective in protecting A. hybridus against phytophagous pest attacks.