Effects of nitrogen supply and population density on plant development and yield components of irrigated sunflower (Helianthus annuus L.)

摘要: Abstract During two seasons the growth and development of an F1 hybrid sunflower ( Helianthus annuus L.) cv. Hysun 30 was tested at nitrogen supply rates between 0 500 kg N ha −1 three population densities: 5, 10 or 15 plants m −2 . Shoot dry matter content per plant increased with increases in applied decreased density. The relationship relative uptake could be described by a single quadratic function over all populations treatments both experiments. Early crop dense there partitioning into stem expense production leaf primordia, decreasing number leaves. Throughout weight % shoot remained greater high than low densities. Floret numbers capitulum were also less but this as result limited receptacle expansion during floret not due to smaller generative area on floral meristem. After initiation, accumulation organs populations. Population density had no effect duration individual leaves lower Low supplies expansion. Increased compensate for effects except where direct occurred, e.g. There response concentration (nitrogen organ weight) separate positive increase application rates. Nitrogen distribution independent organs. percentage initiated florets that produced filled seeds (38%) 5 (68%). Seed number, seed weight, oil yield harvest index increasing Oil affected Fitted surfaces describing plant, terms status are given may useful predicting yield.