Response of Various Promising Lines of Red Rice to Two Levels of Watering following Different P Fertilizer Doses

Abstract

This study aimed to examine the response of various red rice promising lines on several levels of watering and residues of P fertilizers of the preceding rice by conducting a pot experiment testing two treatment factors, i.e. red rice genotypes (19 promising lines) and levels of watering (220 or 330 ml/pot per application), and used residues of P fertilizer doses (0, 100 and 200 kg/ha SP36) applied to the preceding rice plants as the blocks (replications) under Randomized Complete Block design. The results indicated that there were significant interaction effects of the treatment factors on grain yield and weight of 100 grains of the red rice. The P fertilizer doses applied to the preceding rice plants also affected grain yield of red rice, and reduction in levels of watering significantly reduced grain yields, most possibly due to significant increase in the percentage of unfilled grains, which had the most significant negative relationship with grain yield. The genotypes showing the highest yield potential under sufficient watering appeared to be most adversely affected by reduction in levels of watering, such as G1, G2, G8, G9, and G18, with grain yield of 20.47, 18.04, 17.86, 16.85 and 18.27 respectively. However, there were three genotypes having relatively high grain yield showing non-significant effect of reduction in watering level, i.e. G4, G5 and G17. Levels of P fertilization to the preceding rice plants also significantly affected grain yield of the following rice plants, most probably due to their effects on the percentage of unfilled grain number.