Comparison of forage yield and leaf area index of some local and foreign alfalfa (Medicago sativa L.) genotypes

This study was executed to compare forage yield and leaf area index of different alfalfa genotypes for two years and also, to estimate of LAI via leaf weight and plant height during 2011 and 2012. Twenty local and forigen alfalfa genotypes were planted in a RCB design with three replications in spring, 2011 at Seed and Plant Research Institute (SPII), Karaj, Iran. Two-years analysis of variance indicated significant diferent among genotype's means for fresh and dry forage yield in which Bami x Yazdi, Mesa sersa and KFA17 genotypes with 41.99, 39.84 and 39.15 (t ha-1) fresh forage yield and 9.75, 9.41 and 9.16 (t ha-1) dry forage yield were the most forage production, respectively. Despite the significanat difference among genotypes for leaf to stem ratio, there was no significance difference for LAI. The results showed that the fast, accurate and low-cost estimation of LAI is possible through leaf weight and plant height. In this study, leaf weight trait (especially the fresh leaf weight) had more efficiency than plant height in estimating leaf area index through a linear model (without constant) with high coefficient of determination (R2 ≥ 94). It was resulted that every 100 gr of fresh and dry leaf and 10 cm of plant height of alfalfa had 0.33, 1.51 and 0.25 m2 leaf area, respectively.