Imagine you grow rice on the banks of the Sinú River in Montería (Colombia) and, even though you have done everything that must be done to keep a good crop, when the time comes for harvesting, you realize the spikes that were supposed to hold rice grains are empty. Devastating, isn’t it?
Now imagine that a team of scientists is recreating the same environmental conditions from Montería—i.e. temperature, humidity, sunlight—in a chamber of about 12 square meters, with a capacity to hold up to 264 rice plantsi, and that its main goal is to identify the factors affecting your crop and producing empty grains. Encouraging, isn’t it? Then this article may be of interest to you.
The key impact on production
According to data from Colombia’s National Rice Growers Association (Fedearroz) and the National Administrative Department for Statistics (DANE, its Spanish acronym), marked decrease in rice production in Colombia has been seen in recent years, partly attributed to the increase in the presence of the limitation commonly known as grain sterility.
“Grain sterility is the result of a mixture of different factors interfering with grain filling and it has multiple causes”, as explained by Gloria Mosquera, Plant Pathologist of the Agrobiodiversity Research Area from the International Center for Tropical Agriculture (CIAT). Mosquera adds that when yields decreased in Colombia, many hypotheses came up to explain the causes of this problem “it could be either temperature, the combination of temperature and high humidity conditions, or pathogens; thus it became mandatory to conduct a study to determine what was affecting the rice crop along the different rice-growing areas of the country.”
This is how CIAT and Fedearroz joined efforts to submit a proposal to the Department of Science, Technology and Innovation of Colombia (Colciencias), which was approved in 2014 and is being conducted in three regions where high grain sterility has been reported and Fedearroz has a presence: the Caribbean (Montería, Department of Córdoba), the Center (Saldaña, Department of Tolima), and the Llanos Orientales (Santa Rosa, Department of Meta).
From the field to the chamber
The first stage of the research project focused on setting up field studies in the three selected areas, with four sowing dates and different varieties. “We wanted to collect as much information as we could, not just on climate conditions, but also on how climate conditions are affecting the physiology of the rice plant and, simultaneously, measure a series of parameters related to the presence of Burkholderia glumae, the causal agent of the bacterial panicle blight disease,” says Gloria Mosquera.
To complement field studies, a stage involving controlled conditions assays was designed. For this purpose, a Conviron BDW120 growth chamber was acquired, in which specific climate profiles were created for every stage of development of the crop (vegetative, flowering, and ripening). The temperature, relative humidity, and sunlight profiles corresponding to sowing dates showing the highest and the lowest yields were selected to be simulated in the growing chamber.
In addition, the growth chamber has other parameters especially adapted to the requirements of this study: A LED (light-emitting diode) lightning system that does not increase temperature inside the chamber; temperature ranges from 4 to 40 degrees when the lights are switched off, and from 10 to 40 when the lights are on; and a relative humidity of up to 90 % with the lights off, and 75 % with the lights on (See Infographic).
“Our aim is to validate the performance of the genotypes under evaluation in the four different regions and identify limiting biotic and abiotic factors that can affect the final yield of varieties,” says Alexandra Peña, Research Assistant in Rice Physiology at CIAT.
The first stage of the project has been completed, and it consisted of the screening and phenotypic characterization of varieties. The second stage corresponds to the identification of promising parents, and it will conclude with the breeding stage, carrying out crosses between Colombian rice varieties and genotypes identified as tolerant of the biotic and abiotic factors under evaluation.
What is expected
Although it is too soon to talk about results, it is expected that this study will find a rice genotype that adapts better to the climate conditions of each region. “What we can assure is that the growth chamber was ideal to carry out the bacterial inoculations. Therefore, the conditions to simulate this kind of biotic stress were very good,” says Peña.
Now, it is necessary to reach the project goals; however, the research team conducting the study is already thinking of future uses for the growth chamber. “Initially, rice limitations in Colombia should be a priority , but further this infrastructure could be used to evaluate how different varieties from different regions of Latin America respond to a specific stress,” says Mosquera, referring to the possibilities that the chamber brings to FLAR. “The benefit is not limited to this type of infrastructure, but also regards the different methodologies and protocols that have been developed and that can be adapted for evaluations; for example, in the case of FLAR, cold tolerance simulating some climate profiles of the Southern Cone,” concludes Mosquera.
After a chamber maintenance and disinfection stage, a new trial will be set up. This time, when we open the doors of the growth chamber, we will find ourselves under the conditions of the Tolima lowlands, which will later become those of the Llanos Orientales and, at the end of the third year of the research study, those of any region in the world.
iAmounts may vary. According to the design of this study, cylindrical pots with a diameter of 10 cm and a height of 40 cm were used, and they were placed on movable, flooded trays.