پژوهشنامه اصلاح گیاهان زراعی (Oct 2023)
Introduction of "Nafis" the First Iranian Improved Alfalfa Synthetic Variety
Abstract
Extended Abstract Introduction and Objective: Alfalfa (Medicago sativa L.), as the "queen of forage plants", is the most important fodder plant all over the world, including Iran. One of the common methods in alfalfa breeding is the improvement of synthetic verities. Numerous research activities for breeding and cultivation of alfalfa have been done in Iran, but so far only two improved populations have been introduced. This research was done to introduce the first synthetic variety of alfalfa using alfalfa-rich germplasm. Materials and Methods: For evaluation of the general combining ability of Azarbaijan alfalfa ecotypes with polycross test and selection of synthetic variety parents, 30 native ecotypes were collected from the Azarbaijan region, and polycross nurseries were conducted in East Azarbaijan Agricultural and Natural Resources Research and Education Center, AREEO, Tabriz, Iran. The 30 half-sib families resulting from polycross nurseries were planted individually in pots and 30- day old seedlings were transplanted to the field and various traits were measured for 3 years. Based on 30 half-sib family's evaluation, 11 ecotypes were selected as parents for synthetic variety. The selected superior ecotypes were polycrossed under controlled conditions and the synthetic variety was produced. The synthetic cultivar was evaluated in several projects and several locations over several years along with parental ecotypes and control cultivars. Results: Statistical analyses showed significant differences among alfalfa half-sib families and it is possible to select parents. The narrow sense heritability values of fresh and dry forage yield, plant height, and ratios of the fresh and dry weight of leaves to the fresh and dry weight of stem were estimated as 51%, 50%, 46%, 11%, and 19% respectively. According to the ability of the general combination of ecotypes and especially based on fresh and dry forage yield, the top eleven ecotypes were selected for synthetic seed production. Considering 30% selection intensity, the expected genetic gain response for fresh and dry forage yield was calculated as 3.2 and 1.58 tons, respectively, which was expected to be 18% and 17.5% for fresh and dry forage yield, respectively. The ratios of fresh and dry weight of leaves to fresh and dry weight of stem showed low narrow sense heritability, so the expected genetic gain responses for them were very low. Conclusion: Based on the results of several studies, the average yield of fresh and dry forage yield of the synthetic variety was 38609 and 10231 (Kg/ha), respectively. The superiority of this variety for fresh and dry forage yield in comparison with control cultivar was about 22%. The results of several research projects showed that the improved modified synthetic variety has the necessary superiority to be introduced as a new agricultural variety to the farmers for widespread cultivation and introduced and it was introduced as the first synthetic variety named Nafis.
