Selection of rice genotypes (Oryza sativa) with high nitrogen agronomic efficiency in an Acuic Durixererts soil, central-southern Chile
C. Quezada, S. Hernaíz, I. Vidal, R. Alvarado, R. Gallegos, and W. Yañez. 2013. Selection of rice genotypes (Oryza sativa) with high nitrogen agronomic efficiency in an Acuic Durixererts soil, central-southern Chile. 40(2): 375-385. Nitrogen agronomic efficiency (NAE) is a key factor that has not been considered in rice breeding programs. The objective of this study was to evaluate nitrogen agronomic efficiency in twenty rice genotypes in an Acuic Durixererts soil (Quella Series) located in Chile's south central zone (36°04'S, 72° 0'W) over the 2008-09 growing season. The field experiment was carried out in a complete randomized split-plot block design with five N treatments of 0, 50, 100, 150 and 200 kg ha-1 and twenty genotype sub-treatments. The following agronomic characteristics of the crops were measured: yield, grain fill percentage, and nitrogen agronomic efficiency. The N level had a significant effect on grain yield, NAE and the number of panicles per m². Highly significant differences in all parameters evaluated were observed between genotypes. The nitrogen x genotype interaction had significant effects on plant height, 1000-grain weight and the grain fill percentage. The best performing rice genotypes were as follows: Quila 233006, Quila 223202, CINIA 857, and RQuila 17 with a 50 kg N ha-1 dose and Ámbar, RQuila 17 and Quila 242105 with 100 kg N ha-1 dose. These genotypes had high NAE and yield components that may be of use when producing new cultivars. Our results demonstrate the importance of selecting rice genotypes with greater NAE and considering this parameter when making N fertilizer recommendations.