Effect of growth regulator on seed yield and yield components of alfalfa

Effect of growth regulator on seed yield and yield components of alfalfa was studied in Inner Mongolia from March to October 2004 with random block experiment design. The ethephon, paclobutrazol and NAA were used as growth regulators with 4 concentration treatments for each regulator. The results showed that ethephon and NAA increased the number of inflorescence per unit area, number of podsetting inflorescence per unit area and number of pods per inflorescence. NAA increased mean single seed weight. The highest potential seed yield could reach 2 243.68 kg/hm2 and was increased by 72% while the concentration of ethephon was 2.0 kg/hm2. The highest potential seed yield could reach 1 675.71 kg/hm2 and was increased by 28.6% whole the concentration of paclobutrazo was 0.8 kg/hm2. The highest average weight of single seed could reach 2.35 mg while the concentration of NAA was 0.08 kg/hm2.