Response to Rates of Nitrogen Fertilizer Application of F4 Progenies of Composite Crosses Between Local Rice Variety (Mueang Nga) and High Yielding Variety (Thadokkham7) of Lao PDR

Abstract

The aim of this study was to select and evaluate F4 progenies under different nitrogen applications. Three composite crosses (CC) were made from populations of local rice variety (Mueang Nga, MGN) crossed with an improved variety (TDK7). F2 to F4 progenies were selected in three N rates (0, 60 and 200 kg N/ha). Evaluation of F4 progenies was conducted in the field experiment in dry season. Results indicated that means grain yield and ranges of segregation of the improved F4 populations increased with N application at N200 but not for N60. Means grain yield for the three CC populations were 21.0, 18.6 and 26.7 g/plant when grown in 0, 60 and 200 treatments, respectively. Selection for the best 20% of each population was made. Selection differential was highest when selected under N200. Selected populations will be evaluated in with and without N applications in the next season.