STYDY OF SOME GE‎NET‎IC PARAMETERS IN FABA BEAN

The importance of assessing the ge‎net‎ic parameters comes in knowing how the ge‎net‎ic factors are transmitted from one generation to another, as well as their relationship to each other and their effect on determining the ph‎enotypic of the plant. And this is through knowing the ge‎net‎ic behavior and the nature of the ge‎net‎ic action, which is of great importance in determining the appropriate method for breeding and improvement. Selection for a high yield in crops, including faba bean, requires knowledge of the nature and amount of varia‎nce in germplasm because ge‎net‎ic differences are desirable for plant breeders. The success of any breeding program must depend on the desired ge‎net‎ic varia‎nce present in the plant community, and had it not been for the occurrence of these variants, the plant species that surpassed their parents in productive and qualitative characteristics would not have been found. In view of the increasing demand for the crop of faba bean as an important food and medical source for humans, as well as the absence of breeding stations concerned with preserving the varieties cultivated in the country or developing new varieties with desirable production and quality specifications, for the purpose of advancing the current reality of producing this crop, researchers have devoted their efforts to exploit the means and ge‎net‎ic information they have available as tributaries of breeding and improving this crop, where many plant breeders were interested in the phenomenon of heterosis, and it was exploited in the development of many hybrids with high productivity and good quality.


INTRODUCTION
Legumes are an important source of protein in many countries of the world and the countries of the Near East and North Africa, and they are an essential source for some of them (Tewodros et al., 2015 andGemechu et al., 2016). Alhajj et al., (2019) stated that China is one of the largest producers of Studies confirm that the Mediterranean basin is the original home of faba bean, followed by Ethiopia, and Egypt is considered one of the main Arab countries in the production of Studies confirm that the Mediterranean basin is the original home of seed faba bean, and it is next to Ethiopia. In Iraq alone, the local production of Iraq for the remainder and according to the governorates reached 49.861 tons of green pods, with a cultivated area of 24966 dunums, with an average productivity of 1997.2 kg/dunum (Central Statistical Organization, 2019).The percentage of protein in dietary legumes ranges between (20-40%), which contain important amino acids such as Methionine and Cystine, and the percentage of protein varies among the different types, which are controlled by ge net ic s and environment (Asnakech et al., 2016 andMesfin, 2019). Faba bean (Vicia faba L.) is one of the most important crops of the leguminous family Fabaceae, and its importance stems from its use as food for humans because its pods and seeds contain essential nutrients important for humans, such as carbohydrates, amino acids, vitamins, fatty substances and a number of other nutrients (Gnanasambandam et al., 2012 andSallam et al., 2015 ). As well as their seeds contain a high protein content (Kumar, 2016), this makes this crop of nutritional importance necessary to compensate for the high price of animal protein (Abdul-Halitan, 2010 andFekadu et al., 2012). Its plant residues are also used as feed for livestock feeding, in addition to its importance in increasing soil fertility and improving its granular composition, as it is included in agricultural rotations due to the ability of this crop to stabilize free atmospheric nitrogen in the soil by means of root nodes of pests , Currently, soil acidity is a major constraint of faba bean production in the highlands of Ethiopia as it associates with low nutrient availability (Endalkachew et al. 2018 ;Mesfin et al. 2019 ;Mesfin, 2020 a,b).

GE NET IC PARAMETERS Heterosis
The phenomenon of heterosis is one of the ge net ic parameters that plant breeders have applied in many crops, including legumes, in order to improve their productivity in quantity and quality, this phenomenon is considered as a method for direct selection of hybrids that are characterized by high yield, abundance in vegetative growth, regularity and homogeneity of their plants. This phenomenon has been studied in plants of the leguminous family, including faba bean, by a number of researchers, AL-Hamdany (2012)

Combining Ability
The idea of using G.C.A. and S.C.A. was suggested by Sprague and Tatum (1942), who were the first to use diallel crosses to obtain varia nce of the G.C.A. and S.C.A. of coalescence in order to infer from them the type of gene action, and for the purpose of determining the best parents to use in breeding programs. It gives an indication of a dominant gene action ( Ejigu et al., 2016). Faba bean are one of the crops dealt with in studies of this type, and their results differed according to the different types, varieties and breeding methods used in the study Ibrahim (2010)

Ph enotypic , Ge net ic and Environmental Varia nce
The researchers have worked to divide the ph enotypic varia nce into environmental varia nce , which is the difference between plants with similar genotypes and cultivated in different environmental conditions, The appearance of the trait is the final result of the overlap of genotype and environment, and ge net ic varia nce , which is the difference between plants with an asymmetric genotype grown under a single or controlled environment (Sahoki, 1990). Fikreselassie and Seboka (2012) in obtained high ge net ic varia nce of W.100 S. . Al-Taweel et al. (2019) indicated high ge net ic and ph enotypic varia nce of P.H. characteristics , W.100 S. , S.Y. and B.Y. . Fatih (2020) concluded that the coefficient of ge net ic and ph enotypic varia nce was high for the F.D. , P.H. , N.S.P.P. , W.100 S. and S.Y.. It is an estimate of ph enotypic and ge net ic variances in faba bean it was found that the ge net ic and ph enotypic variances , as well as coefficient of ge net ic and ph enotypic varia nce , were high for the characteristics of the N.B.P , N.P.P., G.P.Y. , S.Y. and B.Y.. This is in agreement with what has been obtained (Ahmad, 2016and Praveen et al., 2017and Fatih et al., 2017and Behailu et al., 2018.

Herita bility and Exp ected Ge net ic Adva nce
Two concepts of herita bility have been defined, the first of which is herita bility ratio in the narrow sense in which only additive ge net ic variance enters, the second is the herita bility ratio in the broad sense, and the total ge net ic variance is taken into account (Allard, 1960). The first concept is more accurate in determining the electoral program, and both types of inheritance are important for plant breeders, and the estimation of which of them depends on the breeding material that the plant breeder works on, which is the measure of the relationship between parents and children (Lush, 1943).
One of the objectives of the plant breeding and improvement programs is to obtain highyielding, good-quality varieties. Among these programs is the selection that was used in all crops, as it was developed through several desirable varieties, selection is affected by both the varia nce in the community in which selection is required and the intensity of selection and herita bility , where these factors enter into the equation of estimating the exp ected ge net ic adva nce of the quantitative trait, and estimating the ge net ic adva nce is the largest application of the quantitative ge net ic theory in plant breeding and improvement programs, Johanson et al. (1955) indicated that the exp ected ge net ic adva nce is a product of both the selection intensity, herita bility and the ph enotypic standard deviation.

CONCLUSIONS
Selection for higher yields in crops, including the faba bean, requires knowledge of the nature and amount of varia nce in germplasm because ge net ic differences are desirable for plant breeders, The success of any breeding program must depend on the desired ge net ic variants that are present in the plant community, and had it not been for the occurrence of these variants, the plant species that surpassed their parents in productive and qualitative characteristics would not have been found.