1- University of Maragheh
2- Agricultural Research, Education and Extension Organization (AREEO)
2- Agricultural Research, Education and Extension Organization (AREEO)
Abstract: (13 Views)
Introduction and Objective: Providing fodder for livestock is one of the most important limiting factors for livestock breeding and production in Iran. The diversity of forage plants in Iran is remarkable, and proper use of this diversity requires careful planning to produce desirable varieties that are adapted to different environmental conditions while using this unique diversity. Lathyrus sativus is a seed legume that grows in semi-arid and arid regions. Lathyrus is an annual leguminous crop that is cultivated for animal or human consumption. This genus has several beneficial agronomic characteristics, such as high grain production capacity and high protein content of its seeds. Grass pea has high tolerance to drought stress and moderate tolerance to salinity. Grass pea grows rapidly in spring and does not require much irrigation, and therefore can play an important role in providing part of the required fodder without the need for abundant irrigation. The most important characteristics that distinguish this plant from other legumes include its high yield potential, protein content, nitrogen fixation, tolerance to salinity, drought, and flooding, which have made it play an important role in crop rotation, soil structure improvement, and weed and disease reduction. The main basis of any successful crop breeding program is the existence of a rich and diverse germplasm collection. Knowledge about the amount, type, and size of diversity in germplasm and the genetic relationships of breeding materials can be a valuable tool in crop breeding strategies, and evaluating genetic diversity is one of the most important steps in introducing new varieties. Basically, the prerequisite for responding to desirable selection in any breeding program is the existence of three important factors: sufficient genetic diversity, high selection intensity, and high heritability for the desired trait. The efficiency of selection for a trait depends on the relative contribution of genetic and non-genetic factors to the occurrence of phenotypic differences, which is expressed by heritability. Heritability is an important factor in determining the appropriate method for improving a trait in breeding programs and is also an indicator of how effective selection methods are in improving the trait. It is difficult to improve populations for traits with low heritability through direct selection, and conversely, selection for traits with high heritability is useful. For this reason, the amount of heritability can provide a context for the expected results of selection. Since high heritability only indicates the effectiveness of selection based on phenotypic efficiency and does not indicate any indicator of the amount of genetic progress of individuals, the index of genetic gain can be more effective in selecting genotypes.
Materials and Methods: In order to investigate the genetic diversity, variance components and heritability of 16 promising lines of grass pea along with the Naqadeh control cultivar, a study was conducted at four research stations of Gachsaran, Kohdasht, Mehran and Shirvan in a completely randomized block design with three replications in three consecutive years from 2017 to 2019. The evaluated traits were 100-grain weight, grain yield, forage dry weight, forage fresh weight, number of grains per pod, number of pods per plant, plant height, number of days to grain maturity and number of days to flowering.
Results: The combined analysis of variance showed that the effect of year, location and the interaction effect of year × location were significant for all measured traits. The studied genotypes showed significant differences for the traits, number of days to flowering, number of days to grain maturity, forage fresh yield, forage dry yield and grain yield, which indicates genetic differences between the genotypes in terms of yield traits. The interaction effect of year × genotype was also statistically significant for the above traits, meaning that genotypes had different yields from year to year and did not have yield stability. The results also showed that the interaction effect of genotype × location was significant for the traits days to flowering, days to grain maturity, forage dry yield and grain yield, which indicates that the response of genotypes was not the same in different locations. In other words, genotypes had specific adaptations and, in each location, a specific genotype had higher yield potential. The three-way interaction effect of year × location × genotype was significant for the above traits, meaning that genotypes showed different yields in different combinations of year and location, as well as fluctuations in the order of genotypes and had different status. Plant height had the highest coefficient of phenotypic variation, and days to flowering and days to grain ripening had the lowest coefficient of phenotypic variation. The highest coefficient of genetic variation was related to grain yield, and the highest broad-sense heritability was related to forage yield and grain yield.
Conclusion: In general, it can be concluded that there was variation among the grass pea genotypes, which can be used in breeding programs, considering the genetic and environmental components of the variance.
Materials and Methods: In order to investigate the genetic diversity, variance components and heritability of 16 promising lines of grass pea along with the Naqadeh control cultivar, a study was conducted at four research stations of Gachsaran, Kohdasht, Mehran and Shirvan in a completely randomized block design with three replications in three consecutive years from 2017 to 2019. The evaluated traits were 100-grain weight, grain yield, forage dry weight, forage fresh weight, number of grains per pod, number of pods per plant, plant height, number of days to grain maturity and number of days to flowering.
Results: The combined analysis of variance showed that the effect of year, location and the interaction effect of year × location were significant for all measured traits. The studied genotypes showed significant differences for the traits, number of days to flowering, number of days to grain maturity, forage fresh yield, forage dry yield and grain yield, which indicates genetic differences between the genotypes in terms of yield traits. The interaction effect of year × genotype was also statistically significant for the above traits, meaning that genotypes had different yields from year to year and did not have yield stability. The results also showed that the interaction effect of genotype × location was significant for the traits days to flowering, days to grain maturity, forage dry yield and grain yield, which indicates that the response of genotypes was not the same in different locations. In other words, genotypes had specific adaptations and, in each location, a specific genotype had higher yield potential. The three-way interaction effect of year × location × genotype was significant for the above traits, meaning that genotypes showed different yields in different combinations of year and location, as well as fluctuations in the order of genotypes and had different status. Plant height had the highest coefficient of phenotypic variation, and days to flowering and days to grain ripening had the lowest coefficient of phenotypic variation. The highest coefficient of genetic variation was related to grain yield, and the highest broad-sense heritability was related to forage yield and grain yield.
Conclusion: In general, it can be concluded that there was variation among the grass pea genotypes, which can be used in breeding programs, considering the genetic and environmental components of the variance.
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