Rice infestations are rampant in various parts of the world, thereby raising concerns ranging from food security to sustainability. Blast disease sets out to be one of the most prevalent rice diseases that farmers and other stakeholders fight with globally. Ghimire et al.’s (2018) research elucidate various genotypes that are efficacious in countering, among other diseases, blast disease. This paper will deconstruct and analyze the research by Ghimire et al.’s (2018) by shedding light on its various critical aspects and sections.
Purpose
The purpose of the study is to establish the virulence of Magnaporthe grisea isolates on rice genotypes. In effect, the study plays a vital role in helping one understand the key components of blast disease that makes it resistant. Thus, it will be possible to manage the disease more easily, hence more profitability and sustainability in the long run. Further, rice is amongst the world’s top sources of food and is also major cash and food crops in several countries. Therefore, the study has inestimable benefits through its contribution to global food security.
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Research Question
The major research question that is apparent in the study is: What is the effect of various rice genotypes on the development and prevalence of rice blast disease?
The research question can be broken down further as follows.
What is the severity of blast disease in rice genotypes with various isolates?
How does disease development correlate with pathogenic variations?
What locations and geographical factors influence the screening of rice genotypes against leaf blast?
How do the various leaf blast isolates react with diverse rice genotypes?
Investigation Design
The authors do not explicitly mention any procedural errors that they encountered through the study. Nonetheless, they note a significant attempt to minimize the error margin which may have a significant effect on the results as well as the conclusions derived from the research. The independent variable is rice genotypes while the dependent variable is leaf blast isolates. Rice genotypes included in the research design are 10, which are resistant to the blast isolates. These rice varieties had diverse reaction levels to leaf blast and helped in determining the isolates’ virulence. The 10 genotypes were also found to be Highly Susceptible (HS) to Resistance (R). Figure 1 below shows a table listing the ten genotypes and codes that they were assigned in the study.
Figure 1 . Genotypes used in the study (Ghimire et al., 2018).
On the other hand, the research design encompassed five leaf blast isolates representing blast disease, which were exposed at various levels to the rice genotypes. The blast disease pathogen (Pyricularia grisea), which the researchers obtained through isolation, was exposed to each of the various genotypes under various conditions. Disease scoring was initiated to help assess the various levels of prevalence using a zero to nine scale. Further, Ghimire et al. (2018) find that some isolates have an insignificant difference in terms of their races, which is determined by their geographical location. Thus, there is a need to carry out studies in locations with varying conditions for more accuracy.
Data
The study employed quantitative data as the chief source of data, which was gathered through real-time laboratory tests and a field study. While the ten selected rice varieties provided an objective and wide-range data, some of them are slightly similar which poses the risks of redundancy. The sample size is thus unreasonably big which may pose the challenge of accumulated error. Therefore, it would be more effective costly and even in terms of time spent during the survey, to minimize the sample size by narrowing the genotypes to those showing the highest disparity in nature and resistance abilities.
Further, as the data used research is primarily quantitative, it is critical to consider employing qualitative data as well. Qualitative research would take several forms such as investigative methodologies. In essence, data collection would entail looking into the naturalistic techniques employed to grow and monitor the genotypes. Qualitative data has some advantages over the predominantly used quantities of data. Qualitative data entails observing a study with greater detail since data collection is not subjected to any metrics. As a result, the researcher will be in a better position to identify and understand insights as well as opportunities that a study brings.
Results & Analysis
One of the most significant results in the research was that two among the ten rice varieties used in the study exhibited the lowest mean value resistance of 1.6. The two genotypes include IR 87760-15-2-2-4 (V1) and IR 70210-39-CPA-7-1 (V2) and thus represented the rice varieties that farmers should avoid planting (Ghimire et al., 2018). The main objective of the study is to provide farmers amongst other stakeholders with an informed choice as to which genotypes have the highest resistance to leaf blast disease. Therefore, the knowledge of which varieties have the lowest capability to resist the rice infestation is paramount to and consistent with the research’s direction.
Discussion
Ghimire et al.’s (2018) research assume a hypothesis that rice genotypes are efficacious means of curbing leaf blast disease. The authors argue that many rice growers face the challenge of blast disease, whose adverse effects can lower production massively as observed in some rice-growing regions. Thus, as Ghimire et al.’s (2018) argue, an effective genotype of rice in irrigated regions can withstand the destruction caused by the disease pathogen, Pyricularia oryzae. The yield loss suffered from the disease may go to as high as 90 percent, depending on the variety of rice. While some genotypes are highly susceptible to blast disease, some varieties are highly resistant to the infestation.
As aforementioned, the study involved ten distinct genotypes which were subjected to five diverse isolates of P. grisea, an experimental design that was carried out in a shade house. The study found that while genotypes V1 and V2 portrayed the lowest level of resistant (with a mean value of 1.6), some genotypes showed a significantly high capability of fighting the blast isolates. Genotypes with the highest resistance and included V10 and V8 with mean values of 6.4 and 5,8 respectively. Nonetheless, the reaction of these genotypes depended chiefly on the aggressiveness of isolates. Isolates with the highest susceptible reaction were I5 and I2 with mean values of 4.3 and 3.7 respectively. Isolates such as I1 and I4 showed minimal reaction susceptibility with all genotypes except V10 and V8.
Overall, the researchers were able to identify the genotypes with the highest resistance, that is, V9 and V10, which could withhold the adverse effects of any of the isolate identified. Also, the study was able to elucidate the isolates with the highest adverse effect on rice through the distinct disease index assigned to them.
Conclusion
Upon a critical assessment of the qualitative data obtained from the experiments conducted in a shade house at various locations, the researchers were able to make informed conclusions. The application of genotypes to curb leaf blast disease is indeed effective and efficient under certain parameters. Seven out of the 10 identified isolates were found resistant to the diverse isolates employed in the study. They are IR 87760-15-2-2-4, IR 70210-39-CPA-7-1, NR 11142-B-B-B-9, NR 11130-B-B-B-3, Khumal-10, NR 1105-B-B-16-2, and NR 11105-B-B-20-2-1. Therefore, genotypes are undoubtedly an effective way to fight against the dangerous leaf blast disease on rice.
Nevertheless, the research creates an opportunity for further studies in several crucial aspects. While the study elucidates the various genotypes that farmers and other stakeholders in the agricultural sector could employ in curbing the rice blast disease, it fails to recognize the various geographical variations that may affect the adoption of such rice varieties in diverse locations. Also, the research dwells mostly on genotypes while narrowly shedding some light on the aggressiveness of blast isolates. Thus, there is a need to do a further study on the characteristics, adaptation, and strength of various blast isolates. Therefore, the two research questions that emerge as follow-ups from the conclusion are;
What geographical factors affect the adaptation and growth of rice varieties (genotypes)?
How is the aggressiveness of blast isolates dependent on their nature and adaptation?
Vocabulary
Ghimire et al.’s (2018) study encompass several vocabulary words to which the authors assign meaning intended to help the reader understand the study. Key among these terms are;
P. grisea
The term has been used several terms in the study and is a short form of Pyricularia grisea. P. grisea is one of the most prevalent fungal forms of spore which is produced abundantly in conidiophores.
Magnaporthe grisea
This term is an alias of rice blast fungus, also referred to as rice seedling blight or pitting disease in some regions. The disease is essentially a pathogenic fungus and contains two or more biological species incapable of interbreeding.
Objective Reflection
Ghimire et al.’s (2018) study will undeniably find use in developing one of the most important sectors in the global economy, agriculture. Rice is a staple food to at least a third of the countries in the world, thereby supporting and significantly affecting the living standards of millions of people. The research offers a solution to curb a predominant rice disease, blast fungus, whose adverse effects can see massive destruction of a rice plantation. Past solutions that have been proposed, some even implemented, entail the use of fungicides and are, therefore, alarming to the global environmental safety. Genotypes are indeed drivers of sustainability with minimal environmental degradation.
Ghimire et al.’s (2018) research equip the reader with essential information pertaining to the factors affecting the severity of blast disease. This understanding is paramount in deciding which genotypes will be able to withstand the pathogenic attacks of the disease. As the study finds, various isolates will portray diverse aggressiveness to various genotypes. Also, the implementation of the approach suggested by the study is effective and efficient as compared to other models of managing the rice disease.
Personal Reflection
A typical scientific paper leaves the reader more enlivened and open-minded. Ghimire et al.’s (2018) is no exception. The research is well-structured and follows the essentials of a research paper in its design. The paper primarily focuses on agriculture, an area that has always been my interest. Key among the issues identified in the paper are using ecosystem non-threatening models to improve productivity in the long run. Thus, the study is no doubt exciting and informative. In my past and recent encounters, I view Science as a tool with which the society can be made stronger and sustainable. The current global environmental condition is worsening, thereby calling for an alternative, ecofriendly models in not only production but also agriculture. The research, therefore, enabled me to understand non-hazardous approaches that will go a long way to create a sustainable environment if well implemented. One of the crucial things that I have learned from this assignment is that sustainable ways of making the world a better place are cost-effective and more efficient, as opposed to general perceptions. Indeed, it will cost much less to conserve the ecosystem than destroying it.
References
Ghimire, P., Bahadur, G. K. C., Shrestha, S., & Parajuli, G. (2018) Assessment of Leaf Blast Isolates Virulence on Rice Genotype under Shade House at NARC, Khumaltar, Nepal. Fungal Genom Biol 8: 1000158. doi:10.4172/2165-8056.1000158
