Expected Genetic Gain for several Quantitative Traits in Alfalfa (Medicago sativa L.)

Abstract

In order to determine genetic gain for some quantitative traits in alfalfa ecotypes an experiment was conducted during cropping seasons of 2001-2007 at East Azarbaijan Agricultural and Natural Resources Research Center, Tabriz, Iran. Twenty nine native ecotypes collected from northwest of Iran and an improved variety were used in a polycross nursery. A randomized complete block design was used with 12 replications to ensure the random mating in the polycross nursery. The 30 half-sib families resulted from polycross nursery were planted individually in pots and 30 day old seedlings transplanted in the field and various traits were measured for three cropping seasons in a polycross test. The results of data analysis showed large variations among ecotypes for the traits studied. This indicates that successful selection for desired traits among their progenies is possible. Based on general combining ability, especially for fresh and dry yield, several ecotypes, including Satellou, Gara-yonje, Almard, Legan, Baftan, Khaje, Sivan, Ilan jouj, Dizaj Safar Ali, Khosrovang and Garababa were selected as promising parents for developing synthetic variety. The narrowsense heritability values for fresh yield, dry matter, plant height, fresh leaf to stem and dry leaf to stem ratios were about 60%, 59%, 50%, 11% and 19%, respectively. Using selection intensity of 30%, an increase in fresh yield and dry matter yields were estimated to be 3.2 and 1.58 t/ha, respectively.