Summary
Rice is one of the most produced raw materials in the world, it is essential for food security at a global and national level. Crop yield depends on the use of nitrogen fertilizers; improper use causes environmental and economic repercussions, which is why alternatives are necessary to reduce its impact. The objective of this research was to evaluate mutant rice lines using morphological, physiological and performance variables for the selection of lines with a differentiated response to low nitrogen fertilization. Three rice mutant materials were evaluated: UNA-1182, UNA-1188 and UNA-199; with two doses: 200 kg N/ha and 80 kg N/ha. Morphological variables such as: height and tillering, physiological variables such as: chlorophyll content index (CCI) and vegetation indices (IVs), yield and its components were used to select the line with the best response. It was found that the materials are semi-dwarf plants with scarce and weak tillering. The ICC showed an increase with the age of the culture, however, UNA-1182 did not present changes with the control. The IVs used were indicators of the nitrogen status in the plant, the UNA-1188 and UNA-1199 materials had high values at 200 kg N/ha, while when their dose was reduced the values decreased, while UNA-1182 did not change significantly. The IVs presented the highest correlation coefficients with the ICC when considering all stages. The UNA-1182 showed the highest performance and overall performance components. The UNA-1182 material was selected for its positive behavior in the variables studied; it also recorded the lowest percentage changes in the response with the decrease in N. The mutant materials retained characteristics of the original material and presented a differentiated response to low doses of nitrogen, however, they must continue research so that their response is competitive with the varieties currently available.
Rice is one of the most produced grains in the world, it is essential for food security at a global and national scale. Crop yield depends on the use of nitrogen fertilizers; improper use causes environmental and economic issues and some alternatives are necessary to reduce its impact. The objective of this research was to evaluate mutant rice genetic materials using morphological, physiological and yield components for the selection of lines with a differentiated response to low nitrogen fertilization. Three mutant rice genetic materials were evaluated: UNA-1182, UNA-1188 and UNA-199; with two doses: 200 kg N/ha and 80 kg N/ha. Morphological variables were used such as: height and tillering, physiological variables such as: chlorophyll content index (CCI) and vegetation indices (VIs), yield and its components were used to select the genetic material with the best response. The materials are semi-dwarf plants with scarce and weak tillering. The ICC showed an increase with the crop age, however, UNA-1182 did not present changes with the control. The VIs used were indicators of the nitrogen status in the plant, the UNA-1188 and UNA-1199 materials had high values at 200 kg N/ha, while when their dose was reduced the values decreased. The VIs presented the highest correlation coefficients with the ICC when all stages were considered. The UNA-1182 was the highest in yield and in most of the yield components. The UNA-1182 was selected for its positive behavior in the variables studied and it also recorded the lowest percentage changes in the variables with the decrease of N. The mutant rice genetic materials kept traits of the original genetic material and presented a differentiated response to low doses of nitrogen, however, they must continue research so that their response is competitive with the varieties currently available.
