Open Access Original Research Article

Genetic Variability in Physiological Seed Quality of Maize Genotypes of Different Maturity Groups

J. O. Olasoji, D. J. Ogunniyan

International Journal of Plant & Soil Science, Page 1-10
DOI: 10.9734/ijpss/2020/v32i1730381

A study was conducted to investigate genetic variability in physiological seed quality using viability and vigour tests which were conducted at the seed testing laboratory of Institute of Agricultural Research and Training (IAR&T), Moor Plantation, Ibadan.  The investigational materials consisted of twelve genotypes of maize of different maturity-early, intermediate and late collected from the International Institute of Tropical Agriculture (IITA), Ibadan and IAR&T, Moor Plantation, Ibadan, respectively.  The experimental design used was completely randomize design (CRD) and data was collected for some viability and vigour traits and the data collected were subjected to analysis of variance. Significant differences were found among all the maize genotypes for the characters under observation. Hundred seed weight ranged from 24.6-29.3 g, 18.5-26.6 g, 22.9-29.1 g, standard germination ranged from 54.0-100.0%, 16.0-92.0%, 50.0-100% and accelerate ageing germination also ranged from 6.0-96.0%, 7.0-84.0%, 0-90.0% in the early, intermediate and late- maturing genotypes, respectively. Conductivity ranged from 5.34-17.10 µS/cm/g, 13.7-91.7 µS/cm/g and7.06-33.6 µS/cm/g with mean values of 11.14, 39.23 and 14.05 µS/cm/g in the early, intermediate and late-maturing genotypes, respectively. Variability was smaller in the late-maturing genotypes for Root Number (RN) and Shoot Length (SLT) but higher for both early and late- maturing genotypes. It was concluded from this study that seeds of early-maturing genotypes had significantly higher physical and physiological quality parameters.  All the early materials used for the study tend to be homogenous for all the traits measured and selection should be practiced for hundred seed weight to increase yield potential in maize varieties.

Open Access Original Research Article

Nematoregulatory Effect in Industrial Banana Plantations of Service Plants, Crotalaria retusa, Cajanus cajan, Brachiaria decumbens and Panicum maximum in Fallow Land in the South Comoé Region of Côte d’Ivoire

Yeo Gnénakan, Kassi Koffi Fernand Jean- Martial, N’Guessan Patrick Henri, Fatogoma Sorho, Koné Daouda

International Journal of Plant & Soil Science, Page 11-19
DOI: 10.9734/ijpss/2020/v32i1730382

Aims: In the context of promoting alternative cropping systems with less chemical inputs, studies on the introduction of service plants to reduce pesticide use are a major research effort. The pest caused by plant parasitic nematodes is a major constraint in banana cultivation. One of the main alternatives to the use of chemical nematicides is the rational use of service plants with nematoregulatory properties in crop rotation.

Study Design: The experiment was carried out following Complete randomized design (CRD) with three replications.

Place and Duration of Study: In industrial banana plantations located in the town of Ayamé, 40 km from the town of Aboisso in the forest area of southeast Côte d’Ivoire, between March to October 2016.

Methodology: Among the candidate species, Crotalaria retusa, cajanus cajanus, Brachiaria decumbens and Panicum maximum were evaluated because of their nematoregulatory ability, promoting better sanitation of banana plots infested with nematodes. The experiment tested the behaviour of four service plant species in the field over a period of 8 months during a banana fallow (Musa spp.) populated by nematodes (Radopholus similis, Pratylenchus coffeae, Helicotylenchus multicinctus and Meloidogyne spp.).

Results: The results obtained showed that all the service plants used had a purifying effect on nematodes except Cajanus cajan. Soil and root analyses of host plants show the nematoregulatory action of Crotalaria retusa, Cajanus cajan, Brachiaria decumbens and Panicum maximum by reducing the number of nematodes after 8 months of fallow. Fallows of poacea are the ones that reduce the most Radopholus similis and Pratylenchus coffeae rates. A reduction in the length of fallow time was also noted.

Conclusion: This research has made it possible to improve the management of banana fallow land. This will ultimately help to define, under Côte d'Ivoire environmental conditions, a permanent living cover in association and/or rotation with the banana tree, in order to sustainably improve banana cultivation.

Open Access Original Research Article

Cocoa Farmers’ Perceptions of the Role Played by Tree Diversity and Density on Soil Macro-Fauna Diversity and Density in Cocoa-Based (Theobroma cacao) Agroforestry Systems in Cameroon

Azembouh Roshinus Tsufac, Nyong Princely Awazi, Bernard Palmer Kfuban Yerima

International Journal of Plant & Soil Science, Page 20-28
DOI: 10.9734/ijpss/2020/v32i1730383

Tree diversity and density in agroforestry systems has been found to increase the diversity and density of soil macro-fauna. However, very little is known of the relationship between tree diversity and density in cocoa agroforests and soil macro-fauna diversity and density. This study was therefore undertaken to fill this knowledge gap. A mixed research approach was adopted and data analysis was done using descriptive and inferential statistics. From the findings, most cocoa farmers perceived that tree diversity in cocoa agroforests was either average, high or very high. Most cocoa farmers perceived that tree density on its part was either average or low. Concerning soil macro-fauna diversity in cocoa-based agroforestry systems, most of the cocoa farmers perceived that soil macro-fauna diversity was either average or high. For soil macro-fauna density in cocoa agroforests, most cocoa farmers perceived that soil macro-fauna density was either average, high or low. Through correlation and regression analyses, it was found that a statistically significant (p<0.05) direct non-cause-effect and cause-effect relationship existed between the level of tree diversity and density in cocoa-based agroforestry systems (very high tree diversity, high tree diversity, average tree diversity, low tree diversity, very low tree diversity), and the level of soil macro-fauna diversity and density. This implies that increasing tree species diversity and density leads to increasing soil macro-fauna diversity and density in cocoa-based agroforestry systems. It is therefore recommended that policy makers take drastic measures to ensure greater tree diversity and density in cocoa agroforests in order to ensure higher soil macro-fauna diversity and density.

Open Access Original Research Article

Evaluation of Selected Zambian Popular Sweet Potato Genotypes for Response to Sweet Potato Virus Disease

Joseph Banda, Patrick Chiza Chikoti, Langa Tembo

International Journal of Plant & Soil Science, Page 44-51
DOI: 10.9734/ijpss/2020/v32i1730385

Aim: The objective of this study was to determine the effect of sweet potato virus disease (SPVD) on the beta carotene content, tuber weight and vine weight of selected popular sweet potato genotypes.

Study Design: The experiment was laid as a randomized complete block design (RCBD) with three replications.

Place and Duration of Study: The experiment was conducted for two cropping seasons (2015/16 and 2016/17) at the Zambia Agriculture Research Institute in Chilanga district of Zambia.

Methodology: The uninfected (control) genotypes of Kanga, Chiwoko and Chingovwa were evaluated alongside their SPVD infected genotypes. Genotypic infection was confirmed using molecular approaches, and data was collected at harvest on beta carotene content, tuber weight and vine weight.

Results: The results showed that SPVD affects the yield and beta carotene content of sweet potato. Significant differences (P< .001) for yield performance and beta carotene were observed. The yield reduction in percentage across seasons for all genotypes between the uninfected and infected genotypes ranged from 77% to 79% and 67% to 76% for tuber weight and vine weight respectively. Only Chiwoko exhibited higher levels of beta carotene among the genotypes. However, the SPVD infected Chiwoko genotype compared to the uninfected treatment produced mean beta carotene content of 39.1 µg/g and 91.5 µg/g respectively.

Conclusion: SPVD reduces the tuber weight, vine weight and beta carotene content in infected sweet potato genotypes.

Open Access Original Research Article

Assessing the determinants of soil fertility in cocoa-based (Theobroma cacao) agroforestry systems in the Littoral region of Cameroon

Azembouh Roshinus Tsufac, Nyong Princely Awazi, Bernard Palmer Kfuban Yerima

International Journal of Plant & Soil Science, Page 52-60
DOI: 10.9734/ijpss/2020/v32i1730386

Soil fertility decline is a reality across the globe. Soil infertility has led to falling crop yields for both food and cash crops precipitating both poverty and food insecurity. Poor agricultural practices have often been blamed for declining levels of soil fertility. It was within this framework that this study was carried out to assess soil fertility levels in cocoa-based agroforestry systems in the Littoral region of Cameroon. Through the use of a mixed research approach and descriptive and inferential statistical analysis it was found that the most perceived indicators of soil fertility by cocoa farmers in cocoa-based agroforestry systems were cocoa yields (100%), soil colour (90%), indicator plant species (75%), presence of soil macro-organisms (80%), indicator weed species (65%), growth rate/vigour of the cocoa plant (70%),  and level of compaction of the soil (50%). Chi-square test statistic (X2 = 15.92, p<0.05) revealed that there was a statistically significant difference in cocoa farmers’ perceptions of soil fertility indicators in cocoa-based agroforestry systems. Most cocoa farmers perceived the level of soil fertility in cocoa-based agroforestry systems to be between average (29%) and low (43%). Very few cocoa farmers perceived that soil fertility level in cocoa-based agroforestry systems was very high (5.3%). Chi-square test statistic (X2 = 38.42, p<0.05), revealed the existence of a statistically significant difference in cocoa farmers’ perception of the level of soil fertility in cocoa-based agroforestry systems. Correlation and regression analyses showed the existence of a direct and inverse non-causal and causal relationship respectively between several explanatory variables and soil fertility in cocoa-based agroforestry systems. It was noticed that explanatory variables such as fertilizer/manure application, diversity of tree species in the cocoa agroforests,  diversity of soil macro-fauna in the cocoa agroforests, and density of soil macro-fauna in the cocoa agroforests, all had a statistically significant (p<0.05) direct non-causal and causal relationship with soil fertility in cocoa-based agroforestry systems. Meanwhile, explanatory variables such as age of the cocoa farm, density of cocoa plants in the cocoa agroforests, and application of agrochemicals in the cocoa agroforests, all had a statistically significant (p<0.05) non-causal and causal relationship with soil fertility in cocoa-based agroforestry systems. It is therefore recommended that there should be more organic fertilizer/manure application, more diversity of tree species in the cocoa agroforests, and measures to ensure the diversity and density of soil macro-fauna in cocoa-based agroforestry systems.

Open Access Review Article

Bibliometric and Scientometric Analysis of Scopus-Indexed Literature on Hemp (Cannabis sativa) Breeding

Noel Ndlovu, Leah Banda, Clemence Muitire, Norman Munyengwa, Tatenda Mayaya

International Journal of Plant & Soil Science, Page 29-43
DOI: 10.9734/ijpss/2020/v32i1730384

The elevated research interest and increased cultivation of Hemp (Cannabis sativa) across the globe is significantly driven by its multidirectional industrial uses and medicinal properties. Scientific research publications focusing on hemp breeding plays a pivotal role in bridging the knowledge gap and opening new avenues for upscaling the efficiency of crop improvement initiatives. The identification of prevailing research trends and associations is critical in defining and mapping the trajectories of success in Hemp breeding. The advent of bibliometrics and scientometrics is currently providing a stead platform which fosters effective identification of current research patterns and examination of the applied methodologies, focus areas, and operational constraints. In the context of Hemp research, content assessments provide breeding initiatives with background data needed for exploring various traits of interest and for validating investments and related policies. The main thrust of this study is to perform a bibliometric and scientometric analysis of Scopus-indexed papers covering the field of ‘Hemp Breeding’, between calendar years 1908 and 2020. Data was analyzed using VOSviewer (Version 1.6.16) and Microsoft Excel (2019). The study found 152 papers composed of original articles (105, 69.08%), book chapters (23, 15.13%), conference papers (10, 6.58%), reviews (9, 5.92%), conference reviews (3, 1.97%) and books (2, 1.32%). A significant increment in research publications was observed after 1950. The assessment also indicated that most of the archived research was conducted or reported in the USA (13.82%), Italy (12.5%) and the Netherlands (11.18%). Furthermore, the highest number of papers over the studied period and topic were published by authors affiliated to Wageningen University & Research (16, 10.53%). Index keywords such as Cannabis sativa, hemp, genetic expression, genetic marker, and genetic diversity were covered extensively in the sampled journal editions. A comparative assessment of the results indicated that there is need to scale-up research initiatives targeting hemp trait improvements to cater for the projected high demand and climate change. This can be achieved through strengthening synergistic partnerships and knowledge exchanges across the hemp breeding value chain. This research will assist plant breeders in defining research requirements, determining evidence-based scientific gaps, and recognizing outstanding research institutions for potential intellectual sharing and cooperation.