Effects of seedling age and potassium rate on morphological characteristics related-lodging on yield and yield components of rice (Oryza sativa L.) in Iran

In order to investigate the effect of seedling age and potassium rates on morphological traits relatedlodging on yield and yield components in rice, an experiment was carried out at split plot in randomized complete block design with four replications in Mazandaran province (Iran) in 2009. Main plots was seedling age in three levels including 20, 30 and 40 days and sub plots was potassium rates in four levels including 0, 30, 60 and 90 kg K haG1. Results showed that grain yield had significant difference in seedling ages. Grain yield of 20 and 30 days old seedling was minimum and maximum with 635 and 846 g. mG2, respectively. High potassium application decreased the harvest index and increased the biological yield. Number of effective tillers per plant was effected by potassium rate and was significant at p<0.05 and for 90 Kg K haG1 12.59 and for control 14.60 tillers were produced. Panicle numbers with potassium application was lower than control. Potassium increased plant height and panicle length. The longest third and fourth internodes were observed at 40 day-old seedlings (17.12 and 28.49 cm) and the shortest third and fourth internodes also seen at 20 day-old seedling which was 12.47 and 21.21 cm, respectively.

Rice % Potassium % Seedling age % Lodging % Grain yield