Abstract
Strong correlations (r) between grain yield and other related traits along with high heritability (H2b) and high genetic advance (GA) would help plant breeder to use such traits as selection criteria for high yielding genotype. The objectives of the present investigation were: (i) to assess H2b and GA for 28 traits of 37 quinoa genotypes under low-N (LN), Medium-N (MN) and High-N (HN) organic and mineral fertilizers and (ii) to identify the selection criteria for selecting high seed yield genotypes under each and across the environments. A two-year field experiment was conducted, using a split split-plot design with three replications. Main plots were devoted to two fertilizer types, namely organic (OF) and mineral (MF), sub-plots to three N rates; namely LN (71.4), MN (142.8) and HN (214.2) kg N/ha, and sub sub-plots to 37 quinoa genotypes. The best selection environment for high seed yield/plant that showed the highest H2b and GA estimates and the strongest correlations with seed yield/ha was the low-N organic fertilizer (LN-OF) and the high-N mineral fertilizer (HN-MF) environment. Across all stressed (LN and MN) and non-stressed (HN) environments, the results indicated that seed yield/plant, biological yield/plant, nitrogen use efficiency, branches/plant, leaf area, inflorescence diameter, leaves area/plant, stem diameter, leaf area index, leaves/plant, plant height, 1000-seed weight and inflorescence weight were strongly inter-correlated and strongly correlated with seed yield/ha, had high heritability and high genetic advance and therefore could be regarded as selection criteria in breeding programs for high seed yield of quinoa under N-stressed and non-stressed environments. Further studies should be carried out on other quinoa germplasm to ascertain this conclusion.