Path Analysis of Yield and Quality Traits in Alfalfa

Abstract

An investigation was carried out using 13 alfalfa accessions during 2009 to 2010 and was located on the experimental field of East Azarbaijan Agriculture and Natural Resources Research Center (AZARAN), Iran. The objective of this research was to evaluate positive effect and reliability of yield and quality traits as selection criteria in alfalfa breeding. Significant differences were observed for most of the yield and quality components. Variability coefficients were high for yield components, while quality traits showed relatively low variation. Plant height (PH), number of stems (NS), number of nodes (NN) and leaf size (LS) was positively correlated with plant yield. Crude protein (CP) content was correlated directly with acid detergent fiber (ADF) and natural detergent fiber (NDF) while correlation with crude fiber (CF) was inverse. The direct effect of the number of stems on yield had the highest value (0.698, P<0.01). Direct effect of number of nodes on yield was positive (0.508, P<0.01). Only the plant height had a lower direct than the indirect effect on yield. The direct effects of independent traits on CP were significant (P<0.05), except for trait leaf dry weight (LDW). The direct effect of ADF had the highest value (2.440, P<0.01), which was positive and significant. LDW trait had a negative direct effect on the CP (-0.248, P<0.05), while the indirect effect on the NDF trait on CP was neither high nor justifiable. ADF, CF, NDF and LDW traits had the highest indirect effects on CP trait via correlation with in vitro dry matter digestibility (IVDMD).