The interaction between yield and yield components in cultivated rice and weedy rice in the Nile Delta of Egypt

Rice has economic importance all over the world. However, rice production faces many challenges. Weedy rice is among the most dangerous weeds that attack Egyptian rice in paddy fields and harm rice production. In the present study, five sites in the Nile Delta of Egypt, planted with cultivated rice and infested with weedy rice, were selected to determine the variation in yield traits between cultivated and weedy rice and evaluate the association between yield and other yield traits in cultivated and weedy rice. Red rice had greater flag leaf length, grain length-to-width ratio, number of grains per panicle, panicle weight, and plant height than the cultivated rice. The dry weight (DW) of ten grains increased in the cultivated rice more than in the weedy rice, suggesting that the grain filling was more efficient in the cultivated rice than that in the weedy rice. The number of grains per panicle, grain dry weight, panicle length, panicle weight, and plant height could positively affect high grain yield in cultivated rice. Meanwhile, the length of the flag leaf is positively correlated to grain yield in the weedy rice; however, a high seed shattering rate could negatively affect the net grain yield in these weedy rice plants. The highest weedy rice density over cultivated rice made weedy rice more competitive with cultivated rice by increasing the percentage of grain yield and biomass for the weedy rice against cultivated varieties, and negatively affecting cultivated rice yield.