An investigation of the relationship of rapid canopy development with seed vigor and forage yield in alfalfa (Medicago sativa L.)

One of the unique traits of plants is the conversion of the radiation energy into the chemical energy. Rapid canopy development and closure in crop increases interception of solar radiation and can be resulted in increases crop yield. Therefore, a study was conducted to investigate the relationship between canopy development on forage yield in alfalfa and determination of traits that affect canopy development. The study included 8 alfalfa cultivars (Baghdadi, Bami, Sarbandi, Nikshahri, Mohajerani, Harati, Hamedani and Yazdi). Laboratoral tests (Germination, seed deterioration and seedling growth tests) using completely randomized design and field experiment using randomized complete blocks carried out in 2013 – 2014. The results showed that the correlation of seed vigor (rapid, uniformity and germination percentage) with rapid canopy closure and forage yield were not significant when there were optimum plant density in field. Rapid canopy closure had significant effect on dry forage yield; cultivars with faster canopy development produced more dry forage yield. Leaf area index and crop dry matter at beginning of exponential growth phase and relative leaf area development rate and relative growth rate during the exponential phase, the average of individual leaf area and leaf area ratio were detected as effective traits in rapid canopy closure