TITLE:
Morpho-Agronomic Characterization of Twelve Upland Rice Cultivars in DR-Congo Oxisols
AUTHORS:
Constantin Kalubi Nkongolo, Georges Mupala Muyayabantu, Gaston Ndambo Landu
KEYWORDS:
Gandajika, Upland Rice Varieties, Mineral Fertilization, Yield, Oxisol
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.17 No.5,
May
27,
2026
ABSTRACT: A field study was conducted during the 2025B growing season (February 17 to June 18, 2025) in the Ngandajika territory of the DRC to evaluate the morpho-agronomic potential of 12 rice genotypes under varying soil fertility management. The experiment, located at two sites—Mpoyi (Site 1) and the INERA Ngandajika station (Site 2) utilized a factorial design in Randomized Complete Blocks (RCBs) with two factors: fertilization (no fertilizer control vs. NPK 17-17-17 at 200 kg/ha) and 12 rice varieties. Each site featured two blocks (fertilized and unfertilized) with three replicates. Experimental units measured 2 m × 2 m (4 m2) with 0.5 m spacing between plots and 1 m between blocks, for a total block area of 270 m2 (30 m × 9 m). Fertilizer application significantly increased yields compared to the control: 1224 kg ha?1 (Site 1) and 1211 kg ha?1 (Site 2) with fertilizer, versus 1125 kg ha?1 (Site 1) and 1079 kg ha?1 (Site 2) without, while the site effect was minimal. Improved varieties showed superior performance across both conditions. Under fertilized conditions, NERICA4 (1843 kg ha?1) performed best, followed statistically by IRAT112 (1837 kg ha?1) and NERICA7 (1835 kg ha?1), all of which outperformed INERA7 (1760 kg ha?1), LIENGE (1753.3 kg ha?1), and BOSAU (1737 kg ha?1). Without fertilizer, IRAT112 (1692 kg ha?1) was the top performer, followed by NERICA4 (1667 kg ha?1), BOSAU (1653 kg ha?1), INERA7 (1652 kg ha?1), and NERICA7 (1627 kg ha?1). While these yields are lower than intensive irrigated systems (5000 - 7000 kg ha?1), they are comparable to West African regional averages for upland rice (1600 - 3000 kg ha?1).