Scholarly article on topic 'Analysis of gene action in diallel crosses among some Faba bean (Vicia faba L.) genotypes under Maryout conditions'

Analysis of gene action in diallel crosses among some Faba bean (Vicia faba L.) genotypes under Maryout conditions Academic research paper on "Agriculture, forestry, and fisheries"

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{"Faba bean" / "Gene action" / "Diallel cross" / Rainfed / "General combining ability (GCA)" / "Specific combining ability (SCA)"}

Abstract of research paper on Agriculture, forestry, and fisheries, author of scientific article — H.I.A. Farag, S.A. Afiah

Abstract Seven genotypes of faba bean (Vicia faba L.) were used in carrying out half diallel cross, 21 F1 hybrids and 21 F2 progenies evaluated under well watered and rainfed conditions at the Maryout Agriculture Experimental Station of Desert Research Center. Mean squares of genotypes in F1 and F2 generations showed that the differences due to genotypes were significant for all characters studied under well watered and rainfed conditions. The four parental genotypes; P2, P4, P5 and P6 were the earliest in days to 50% flowering and recorded values raging from 30.88 to 47.98days under well watered and rainfed conditions and the two crosses; P1 ×P3 and P2 ×P7 in both generations under the two treatments. The parental genotype P2 recorded the highest number of branches per plant (7.85 and 6.94 branches) under well watered and rainfed treatments, respectively. While, the two crosses; P2 ×P4 and P2 ×P6 recorded the highest number of pods per plant in both generations under well watered and rainfed treatments. For 100-seed weight the parent Aquadulce (P4) recorded the highest values under well watered and rainfed conditions (95.62 and 71.72g, respectively). As well as the two crosses; P2 ×P5 and P2 ×P6 recorded the highest values for seed yield per plant. Significant positive heterosis and heterobeltiosis were detected for different traits; With respect to seed yield per plant, the seven crosses; P1 ×P7, P2 ×P5, P2 ×P6, P4 ×P6, P5 ×P6, P5 ×P7 and P6 ×P7 had significant positive heterotic effects relative to mid and better parents under the two irrigation treatments. Mean squares of both GCA and SCA estimates were highly significant or significant in both generations for all the studied traits under well watered and rainfed conditions. Variances due to GCA were larger than those for SCA and exceeded the unity were detected for days to 50% flowering in F1 generation under rainfed conditions, No. of branches per plant, No. of pods per plant in both treatments and generations except for F1 generation under rainfed condition, 100-seed weight in both treatments and generations except for the F1 generation under well watered conditions and seed yield per plant in both treatments and generations except for the F2 generation under well watered and rainfed conditions, revealing that the largest part of the total genetic variance associated with different traits being the result of additives types on gene action. General combining ability results showed that the three parental genotypes (P1 (G.461), (P2 (NBL2) and P4 (Aquadulce)) were good combiners for improving most studied traits. Such combinations might have desirable transgressive segregations, provided that the additive genetic system is present in different crosses for increasing plant yield and its components under targeted well watered and rainfed conditions. For SCA, the desirable inter-and intra-allelic interactions were presented in the cross P6 ×P7 in the two generations under both treatments along with P1 ×P2 in the F2 generation under both treatments, P1 ×P5 in F1 and F2 generations under well watered and rainfed conditions respectively, P1 ×P6, P2 ×P5 and P4 ×P6 in F1 under both treatments and the three crosses; P1 ×P7, P3 ×P4 and P3 ×P5 in F1 generation under well watered conditions showed significant positive effects for 100-seed weight. Moreover, seven F1′ P1 ×P7 in both generations and under the two treatments, P1 ×P4 in the F1 generation under well watered conditions, P2 ×P5, P2 ×P6, P4 ×P6 and P5 ×P7 under F1 generation under both treatments and P6 ×P7 in the F2 generation under rainfed conditions possessed significant positive effects for seed yield per plant. These crosses might be of interest in breeding programs to produce pure lines while most of them involve at least one good combiner for the trait in view.

Academic research paper on topic "Analysis of gene action in diallel crosses among some Faba bean (Vicia faba L.) genotypes under Maryout conditions"

Annals of Agricultural Science (2012) 57(1), 37-46

Faculty of Agriculture, Ain Shams University Annals of Agricultural Science

www.elsevier.com/locate/aoas

ORIGINAL ARTICLE

Analysis of gene action in diallel crosses among some Faba bean (Vicia faba L.) genotypes under Maryout conditions

H.I.A. Farag *, S.A. Afiah

Plant Genetic Resources Dept., Desert Research Center, El-Matariya, Cairo, Egypt

Received 23 June 2011; accepted 3 August 2011 Available online 5 April 2012

KeywordsFaba bean; Gene action; Diallel cross; Rainfed;

General combining ability (GCA);

Specific combining ability (SCA)

Abstract Seven genotypes of faba bean (Vicia faba L.) were used in carrying out half diallel cross, 21 F1 hybrids and 21 F2 progenies evaluated under well watered and rainfed conditions at the Maryout Agriculture Experimental Station of Desert Research Center. Mean squares of genotypes in F1 and F2 generations showed that the differences due to genotypes were significant for all characters studied under well watered and rainfed conditions. The four parental genotypes; P2, P4, P5 and P6 were the earliest in days to 50% flowering and recorded values raging from 30.88 to 47.98 days under well watered and rainfed conditions and the two crosses; P1 x P3 and P2 x P7 in both generations under the two treatments. The parental genotype P2 recorded the highest number of branches per plant (7.85 and 6.94 branches) under well watered and rainfed treatments, respectively. While, the two crosses; P2 x P4 and P2 x P6 recorded the highest number of pods per plant in both generations under well watered and rainfed treatments. For 100-seed weight the parent Aquadulce (P4) recorded the highest values under well watered and rainfed conditions (95.62 and 71.72 g, respectively). As well as the two crosses; P2 x P5 and P2 x P6 recorded the highest values for seed yield per plant. Significant positive heterosis and heterobeltiosis were detected for different traits; With respect to seed yield per plant, the seven crosses; P1 x P7, P2 x P5, P2 x P6, P4 x P6, P5 x P6, P5 x P7 and P6 x P7 had significant positive heterotic effects relative to mid and better parents under the two irrigation treatments. Mean squares of both GCA and SCA estimates were highly significant or significant in both generations for all the studied traits under well watered and rainfed

Corresponding author. Tel.: +20 2 4444 14 54. E-mail address: hossam_frg@yahoo.com (H.I.A. Farag).

0570-1783 © 2012 Faculty of Agriculture, Ain Shams University. Production and hosting by Elsevier B.V. All rights reserved.

Peer review under responsibility of Faculty of Agriculture, Ain Shams University.

http://dx.doi.org/10.1016/j.aoas.2012.03.006

conditions. Variances due to GCA were larger than those for SCA and exceeded the unity were detected for days to 50% flowering in Fj generation under rainfed conditions, No. of branches per plant, No. of pods per plant in both treatments and generations except for Fj generation under rainfed condition, 100-seed weight in both treatments and generations except for the Fj generation under well watered conditions and seed yield per plant in both treatments and generations except for the F2 generation under well watered and rainfed conditions, revealing that the largest part of the total genetic variance associated with different traits being the result of additives types on gene action. General combining ability results showed that the three parental genotypes (Pj (G.461), (P2 (NBL2) and P4 (Aquadulce)) were good combiners for improving most studied traits. Such combinations might have desirable transgressive segregations, provided that the additive genetic system is present in different crosses for increasing plant yield and its components under targeted well watered and rainfed conditions. For SCA, the desirable inter-and intra-allelic interactions were presented in the cross P6 x P7 in the two generations under both treatments along with Pj x P2 in the F2 generation under both treatments, Pj x P5 in Fj and F2 generations under well watered and rainfed conditions respectively, Pj x P6, P2 x P5 and P4 x P6 in Fj under both treatments and the three crosses; Pj x P7, P3 x P4 and P3 x P5 in Fj generation under well watered conditions showed significant positive effects for 100-seed weight. Moreover, seven Fj' Pj x P7 in both generations and under the two treatments, P1 x P4 in the F1 generation under well watered conditions, P2 x P5, P2 x P6, P4 x P6 and P5 x P7 under F1 generation under both treatments and P6 x P7 in the F2 generation under rainfed conditions possessed significant positive effects for seed yield per plant. These crosses might be of interest in breeding programs to produce pure lines while most of them involve at least one good combiner for the trait in view.

© 2012 Faculty of Agriculture, Ain Shams University. Production and hosting by Elsevier B.V. All rights

reserved.

Introduction

Faba bean ( Vicia faba L.) is one of the most important grain legumes in prone regions of North and East Africa, especially in Egypt. It plays an important role in world agriculture, owing to its high protein content, ability to fix atmospheric nitrogen, capacity to grow and yield well on marginal lands. The production of faba bean is severely limited by several constraints, which include drought and salinity stresses (Algham-di, 2007).

Breeders use two strategies to improve drought tolerance; the first which is rather unspecific is based on the exploitation of heterosis. Heterosis for the yield of faba bean tends to increase under drought stress (Abdelmula et al., 1999). The second strategy is direct selection for drought tolerance and its components (Loss and Siddique, 1997).

Hybrids breeding has been suggested as a solution for improving seed yield and yield stability in the faba bean. Superiority of hybrids over the mid and/or better parents for seed yield is associated with the manifestation of heter-otic effects in important yield components, i.e., number of branches per plant, number of pods per plant and seed index. These heterotic effects may range from significantly positive to significantly negative for different traits depending on genetic makeup of parents (Duc, 1997; Abdalla et al., 1999; El-Keredy et al., 1999; Darwish et al., 2005; El-Hady et al., 2006). Bond et al. (1994) and Abdelmula et al. (1999) reported that faba bean hybrids showed better adaptation to a wide range of abiotic conditions as compared to open pollinated or inbred cultivars and better tolerance to drought stress. While, Omar et al. (1998) suggested that the economic feasibility would be considerably improved if sufficient heter-osis were retained in the F2 generation to make its production of value particularly under stress conditions.

In addition several researchers have stated the significance of both general and specific combing ability effects for yield and other important traits of faba beans (Abdalla et al., 2001; Attia et al., 2002; Attia and Salem, 2006; Hossam, 2010).

The present investigation aimed to understand the nature of gene action and the relative magnitude of heterosis and the combining ability of seven faba bean diverse genotypes in addition to their respective F1 and F2 generations using diallel cross mating design for some agronomic traits under well watered and rainfed conditions.

Materials and methods

Two field adjacent experiments were conducted at the Maryout Agriculture Experiment Station of Desert Research Center (D.R.C.) under two irrigation treatments, rainfed amount only and rainfed + 2 supplemental irrigations given at sowing and flowering stage to study the response of seven genotypes of faba bean (V.faba L.) and their respective F1 and F2 generations. Names, source and pedigree of faba bean varieties or lines are presented in Table 1. In 2006/07 season different genotypes were crossed in a half-diallel mating design under wire cages at the Maryout experimental site and 21 F1 hybrids were obtained. The F2 seeds of these crosses were produced by bagging F1 plants during the flowering period in 2007/08 season and F1 crosses were made to obtai additional F1' seeds. The soil of the site is loamy clay in texture, E.C. 4.53 ds/m, calcareous (34.19% CaCO3) and 0.76% organic matter.

In the 2008/09 season the parental genotypes along with their 21 F1 and 21 F2 progenies were sawn in a randomized complete block design with three replications. Each experimental plot consisted of 3, 1 and 5 rows for parents, Fi and 21 F2, respectively in each replication under both experiments. The

Table 1 Name, origin, pedigree and/or selection history of the seven divergent faba bean genotypes

No. Name Origin Pedigree and/or selection history

1 G461 G3/ILB938 Egypt

2 NBL2 (A2/ILB1179) (ILB3879) 04SEL-1 Egypt

3 L 82009-3 A2/ILB1179 ICARDA

4 Aquadulce ILB1266 Spain

5 NBL4 G716//A2/ILB1179 Egypt

6 L5 ILB 4720 ICARDA

7 L8 ILB3879 ICARDA

ICARDA: International Center for Agricultural Research in the Dry Area.

NBL: Newly bred lines produced through desert research center breeding program for faba bean (Afiah and Abdel-Aziz, 2003 and Afiah et al.,

2007).

Table 2 Monthly average weather data during 2007/08 and 2008/09 growing seasons at Maryout site.

Month Ta (C°) RH%b WSc at 2 m m/s Amount rainfall (mm)

2007/08 season

Nov, 2007 19.80 64.33 2.23 21.00

Dec, 2007 15.50 66.67 2.50 60.90

Jan, 2008 14.20 61.33 2.57 39.10

Feb, 2008 14.67 66.33 2.83 59.30

March, 2008 16.13 62.33 3.20 3.60

April, 2008 18.70 61.33 3.67 5.00

May, 2008 22.13 57.67 3.27 6.20

2008/09 season

Nov, 2008 18.41 61.11 2.07 18.00

Dec, 2008 14.42 63.34 2.33 43.70

Jan, 2009 17.04 58.26 3.08 52.00

Feb, 2009 17.60 63.01 3.40 46.15

March, 2009 19.36 74.80 3.84 10.23

April, 2009 16.46 73.60 4.40 3.29

May, 2009 20.47 69.20 3.92 2.47

a T = Temperature.

b RH% = Relative humidity percentage. c WS = Wind speed.

row was 4 m in length, 0.6 m in width and the plants were spaced within the row at 20 cm. Table 2 shows the meteorological data of the experimental site collected from the meteorological desert research lab during growing seasons. The total rainfed amounts in 2007/08 and 2008/09 seasons were 195.10 and 175.84 mm, respectively. The randomization was restricted by growing parents, F1 hybrids and F2 separately.

Number of days to 50% flowering of plants/plot was recorded during the growth period. At harvest; plant height, number of branches per plant, number of pods per plant, 100-seed weight and seed yield per plant were recorded for each genotype on 10 guarded plants for parents and F1 plants and on 25 plants for F2 from each replicate.

Data were subjected to regular analysis of RCBD on plot mean basis according to Snedecor and Cochran (1989). The heterotic effects of F1 crosses were estimated as percentage over mid parent (Heterosis) as well as better parent (Hetero-beltiosis) according to Fonseca and Patterson (1968).

The 't' test was made to determine whether Fi hybrid means were statistically different from mid parent and better parent means as illustrated by Wynne et al. (1970).

The data were analyzed as a fixed model (Baker, 1978). The diallel design was analyzed according to Griffing's method 2, model (Griffing, 1956).

Results and discussion

Analysis of variances

Mean squares of variance of genotypes in F1 and F2 generations showed that differences among genotypes were significant for all the studied characters under well watered and rainfed conditions (Table 3). This indicates the presence of sufficient genetic variability among genotypes which can be exploited in faba bean breeding program for improving yield and other traits. El-Hosary et al. (2002), Alghamdi and Ali (2004), Kalia and Sood (2004) and Alghamdi (2007) found variation among faba bean genotypes for the same studied traits.

Mean performance

The mean performance of different faba bean genotypes is given in Table 4. P2, P4, P5 and P6 were the earliest in flowering and recorded values raging from 30.88 to 47.98 days under well watered and rainfed conditions and the two crosses; P1 x P3 and P2 x P7 in both generations under the two treatments. Also the crosses; P1 x P5, P2 x P4, P2 x P6, P4 x P6 and P6 x P7 in F1 generation and the two crosses; P3 x P7 and P4 x P5 in F2 generation under well watered treatment and the two crosses; P3 x P7 and P4 x P5 in F1 generation and the three crosses; P1 x P4, P3 x P7 and P4 x P5 in F2 generation under rainfed conditions were the earliest in flowering. Meanwhile, the parental genotype (P7) and the three crosses; P1 x P4, P3 x P5 and P4 x P5 were the latest in flowering in one or both generations under the two treatments. The five crosses; P1 x P7, P2 x P4, P3 x P4, P3 x P6 and P3 x P7 in the F1 generation were the tallest under one or both treatments as well as the five crosses; P2 x P3, P2 x P5, P3 x P7, P5 x P6 and P6 x P7 in the F2 generation under well watered and rain-fed conditions. The parent NBL2 (P2) recorded high values for a number of branches per plant (7.85 and 6.94 branches under well watered and rainfed treatments, respectively). For the number of pods per plant, the two crosses; P2 x P4 and P2 x P6 recorded the highest number of pods per plant in both generations under well watered and rainfed treatments, as well as the cross P3 x P4 in F1 generation under both treatments and the cross P4 x P7 in both generations (40.33 and 72.49 pods) under well watered treatment and F2 generation (56.38 pods) under rainfed conditions.

For 100-seed weight the parent Aquadulce (P4) recorded the highest values under well watered and rainfed conditions (95.62 and 71.72 g, respectively). The two crosses; P2 x P5

Table 3 Mean squares of variance of faba bean genotypes for different studied traits under well watered and rainfed treatments.

Traits SOV Replications Genotypes Error

d.f. 2 27 54

Days to 50% flowering Fi 90.14 329.60** 34.37

F2 45.46 248.72** 38.16

Plant height (cm) Fi 19.18 279.74* 153.92

F2 52.76 274.03** 125.46

Number of branches per plant Fi 4.974 5.99* 3.12

F2 2.22 5.06* 2.61

Number of pods per plant Fi 225.93 537.27** 201.59

F2 259.28 1254.08** 282.02

100 seed weight (g) Fi 91.66 354.63** 8.26

F2 178.99** 379.23** 6.98

Seed yield per plant (g) Fi 169.76 911.45** 311.54

F2 139.38 573.63** 214.25

Days to 50% flowering Fi 91.09 278.42** 31.80

F2 38.88 241.75** 29.80

Plant height (cm) Fi 14.61 259.05** 77.31

F2 33.77 175.38** 80.29

Number of branches per plant Fi 2.88 3.55* 2.04

F2 1.09 4.62** 1.68

Number of pods per plant Fi 145.50 338.71** 122.36

F2 151.37 756.01** 171.56

100 seed weight (g) Fi 61.77 141.06** 5.73

F2 101.47b 182.63** 4.69

Seed yield per plant (g) Fi 116.84 638.55** 188.53

F2 117.41 387.81** 136.82

Well watered treatment

Rainfed treatment

*"**Denote significance at P 6 0.05 and 0.01 probability level, respectively.

and P2 x P6 registered the highest values for seed yield per plant followed by the three crosses; P4 x P6, P5 x P6 and P5 x P7 in F1 generation under well watered and rainfed conditions which had values that ranged from 66.10 to 95.58 g. It is noticed that the crosses which are superior in the number of pods per plant and seed yield per plant significantly exceeded the highest parental genotypes in the two traits. However, none of the F1 crosses exceeded their highest parents in 100-seed weight. From the above mentioned results it could be concluded that the previous superior genotypes can be exploits in faba bean improving programs. Similar results were obtained by, El-Kady and Khalil (1979), Link et al. (1999), Abdalla et al. (2001), El-Hosary et al. (2002), AlGhamdi and Ali (2004), Afiah et al. (2007), Attia and Salem (2006) and Alghamdi (2007).

Heterosis

Values of heterosis percentages relative to mid parents (MP) and better parent (BP) are presented in Table 5. For days to 50% flowering, the desirable negative MP and BP heterotic effects were recorded by the four crosses; P1 x P5, P2 x P7, P3 x P7 and P6 x P7 under both irrigation treatments giving values ranging from —39.26% to —18.39%. However, positive heterotic effects relative to MP were obtained in the five crosses; P1 x P4, P2 x P3, P3 x P5, P4 x P5 and P5 x P6 which ranged from 20.64% to 87.79%. while the two crosses P4 x P5 and P5 x P6 gave a range of 31.36-84.61% relative to BP under well watered and rainfed conditions as well as the two crosses P2 x P4 and P2 x P5 for MP and BP under rainfed condition and the cross P3 x P5 for BP under well watered conditions. For plant height, heterosis percentages relative to mid

and better parents were significant and positive in the cross (P1 x P7)under both treatments and in the three crosses; P2 x P4, P2 x P7 and P4 x P5 under well watered conditions. Regarding the no. of branches/plants the two crosses; P5 x P6 and P5 x P7 exhibited significant positive heterotic effects relative to MP and BP under both irrigation treatments except het-erotic effects relative to BP were not significant for the cross P5 x P6 under rainfed conditions. Also the cross P4 x P5 registered significant positive heterotic effects relative to MP and BP under rainfed conditions for this trait. For number of pods per plant eighteen of the tested crosses gave significant and positive heterosis values relative to MP and BP under well watered and/or rainfed conditions. For 100-seed weight only the cross P2 x P5 exhibited significant positive MP heterotic effect (24.38 g%) under rainfed conditions. With respect to seed yield per plant, the seven crosses; P1 x P7, P2 x P5, P2 x P6, P4 x P6, P5 x P6, P5 x P7 and P6 x P7 had significant positive heterotic effects relative to mid and better parents under the two irrigation treatments which had values that ranged from 33.29 to 96.97 g% for mid parent (MP) and 9.42 to 70.32 g% for better parent (BP). Also significant positive heterotic effects were recorded for this trait by the cross P1 x P5 for MP heterosis (21.30 g%) under well watered treatment, the cross P4 x P5 under well watered and rainfed conditions for MP heterosis and the cross P4 x P6 for MP heterosis under both treatments. It could be suggested that the heterotic effects for seed yield were associated with other yield components. Different values of heterosis might be due to the genetic diversity of the parents with non-allelic interactions which increase or decrease the expression of heterosis (Hayman, 1958). While, Alghamdi (2009) illustrated that heterosis estimates for the majority of different traits indicate that there was sufficient

Table 4 Mean performance of faba bean genotypes (G) for different studied traits under well watered and rainfed treatments. Characters Days to 50% flowering Plant height (cm) Number of branches per plant

Parents Well watered Rainfed Well watered Rainfed Well watered Rainfed

P1 (G.461) 64.ii 46.09 87.67 70.i3 6.67 5.56

P2 (NBL2) 47.98 32.99 84.00 67.20 7.85 6.94

P3 (L 82009-3) 56.i8 55.62 i00.00 83.06 7.67 4.39

P4 (Aquadulce) 42.25 35.06 86.33 69.07 7.00 3.83

P5 (NBL4) 46.43 36.30 87.33 69.87 4.33 3.6i

P6 (L5) 47.85 30.88 98.33 78.67 6.3i 5.83

P7 (L8) 74.9i 53.82 67.52 63.48 5.33 4.44

Crosses Fi F2 Fi F2 Fi F2 Fi F2 Fi F2 Fi F2

Pi • P2 5i.54 65.08 4i.95 53.37 92.00 95.i3 69.00 76.ii 5.67 6.45 4.72 5.38

Pi • P3 48.09 38.38 45.68 3i.47 86.33 90.40 64.75 72.32 4.33 7.04 3.6i 5.72

Pi X P4 7i.97 44.94 53.98 36.85 89.67 98.40 67.25 78.72 2.67 6.i6 2.22 4.93

Pi X P5 42.i4 46.47 3i.60 44.6i i00.33 94.53 75.25 75.63 5.00 5.87 4.i2 4.69

Pi X P6 59.i5 5i.07 44.36 49.03 86.33 75.73 67.57 60.59 5.33 4.69 4.27 3.75

Pi X P7 65.00 52.63 56.59 48.5i i06.85 86.i3 84.i3 68.9i 5.0i 5.28 4.i8 4.40

P2 X P3 62.83 67.42 55.66 58.65 92.27 i07.56 73.8i 86.05 6.67 4.69 5.33 3.9i

P2 X P4 47.02 46.39 44.67 40.36 i06.00 95.07 70.67 76.05 4.33 4.99 3.25 4.i6

P2 X P5 55.06 43.28 45.i7 38.90 92.93 ii4.00 6i.96 9i.20 6.00 3.23 4.50 2.69

P2 X P6 4i.40 57.58 3i.05 55.27 95.9i 99.59 63.94 79.67 4.78 3.8i 3.50 3.i8

P2 X P7 45.50 33.7i 34.i2 30.00 i0i.37 94.80 67.58 75.84 5.i7 3.8i 4.69 3.i8

P3 X P4 46.89 47.32 44.54 42.ii i05.23 79.60 70.i5 63.68 5.33 4.40 4.44 3.67

P3 X P5 73.4i 52.00 60.23 44.i3 i02.40 88.80 72.2i 7i.04 4.33 5.57 3.6i 4.64

P3 X P6 50.5i 50.26 37.88 37.70 i09.73 92.67 87.79 74.i3 5.87 5.57 5.00 4.64

P3 X P7 47.i2 37.62 35.34 28.2i i0i.73 i09.07 8i.39 87.25 5.i4 3.8i 4.90 3.i8

P4 X P5 70.53 44.05 67.00 33.03 i0i.73 99.07 76.30 79.25 5.00 6.i6 4.80 4.ii

P4 X P6 4i.29 53.82 33.88 40.37 90.87 98.97 60.58 79.i8 5.33 4.69 4.27 3.i3

P4 X P7 57.96 59.i5 43.47 55.0i 79.60 90.28 53.07 72.22 6.07 4.99 4.78 3.32

P5 X P6 63.70 50.39 47.77 46.86 i00.29 i06.84 66.86 85.47 7.32 4.69 6.30 3.i3

P5 X P7 6i.57 56.52 46.i8 52.57 92.09 94.20 6i.40 75.36 6.37 3.8i 5.46 2.54

P6 X P7 46.08 60.6i 34.56 56.37 93.87 ii4.27 62.58 9i.4i 5.22 6.i6 4.38 4.ii

LSD 5% 9.60 i0.ii 9.23 8.94 20.3i i8.34 i4.39 i4.67 2.89 2.64 2.34 2.i2

Characters Number of pods per plant i00-Seed weight (g) Seed yield per plant (g)

Parents Well watered Rainfed Well watered Rainfed Well watered Rainfed

Pi (G.46i) 24.00 i9.47 82.99 62.25 56.39 45.ii

P2 (NBLI) 32.i4 2i.67 78.07 58.56 70.30 56.24

P3 (L 82009-3) 23.00 i9.i7 78.95 59.22 57.4i 4i.93

P4 (Aquadulce) 27.4i 20.28 95.62 7i.72 72.77 58.83

P5 (NBL4) 20.24 i2.3i 74.98 56.24 50.93 42.44

P6 (L5) 25.33 i8.59 77.58 58.i9 46.i4 38.45

P7 (L8) i6.67 8.44 75.i3 56.35 37.i5 30.96

Crosses Fi F2 Fi F2 Fi F2 Fi F2 Fi F2 Fi F2

Pi x P2 20.00 28.i3 i3.33 2i.88 76.99 78.8i 52.74 59.ii 50.66 33.95 42.22 22.63

Pi • P3 i5.33 8.i5 i0.22 6.34 6i.37 69.87 47.73 52.40 33.92 22.73 25.98 i5.i5

Pi X P4 22.00 i7.55 i4.67 i3.65 6i.29 76.33 5i.08 57.25 73.40 49.i8 48.93 32.78

Pi X P5 30.25 37.9i 28.96 29.49 77.42 78.06 64.52 58.55 65.09 43.6i 43.39 30.96

Pi X P6 30.00 28.20 23.33 2i.93 8i.37 68.35 65.56 5i.26 37.72 33.57 25.i5 26.86

Pi X P7 26.00 24.44 20.22 i9.0i 74.83 62.86 56.i3 47.i5 74.05 65.90 49.36 52.72

P2 X P3 33.93 47.30 26.39 36.79 70.72 59.40 53.04 46.20 67.i4 59.76 46.i4 47.80

P2 X P4 48.6i 8i.78 3i.37 63.6i 8i.82 68.73 62.82 53.46 73.83 65.7i 59.06 52.56

P2 X P5 34.00 6i.34 25.i9 47.7i 83.79 70.38 65.i7 54.74 93.72 50.6i 74.98 42.70

P2 X P6 40.28 87.9i 30.29 68.38 65.64 55.i4 5i.05 4i.90 95.58 5i.62 76.47 46.92

P2 X P7 36.67 5i.ii 28.52 39.75 65.i6 54.74 50.09 4i.05 6i.07 32.98 47.50 29.98

P3 X P4 4i.55 44.8i 37.07 34.85 80.i6 67.33 60.i2 50.50 58.i4 3i.40 45.22 28.54

P3 X P5 38.67 40.67 26.i8 3i.63 76.49 64.25 57.37 49.97 49.80 33.37 38.73 30.33

P3 X P6 39.60 37.22 30.80 28.95 59.25 49.77 44.44 38.7i 62.96 52.94 50.37 44.05

P3 X P7 24.93 23.44 i9.39 i8.23 6i.79 5i.90 46.34 40.37 36.i3 32.i5 28.90 26.80

P4 X P5 34.47 48.05 26.8i 37.37 82.i8 69.03 6i.64 52.45 73.84 49.47 6i.53 4i.23

P4 X P6 37.73 52.60 29.35 40.9i 8i.70 68.63 62.74 5i.47 83.44 55.90 69.53 46.59

P4 X P7 40.33 72.49 26.47 56.38 60.80 5i.07 47.29 4i.i2 54.89 43.27 45.74 36.06

P5 x P6 28.40 39.59 22.09 30.79 58.76 49.36 45.70 4i.i3 79.32 42.83 66.i0 34.27

P5 x P7 27.92 38.92 i5.29 30.27 74.28 62.40 57.09 52.00 86.74 50.49 67.52 40.39

P6 X P7 38.i7 62.04 24.i9 48.25 79.75 66.99 46.i9 55.83 65.62 54.07 48.33 43.26

LSD 5% 23.24 27.49 i8.ii 2i.44 4.70 4.32 3.92 3.55 28.89 23.96 22.48 i9.i5

Table 5 Heterosis percentages relative to mid (MP) and better (BP) parent of faba bean for different studied traits under well watered

and rainfed treatments.

Characters Days to 50% flowering Plant height (cm) Number of branches per plant

Well watered Rainfed Well watered Rainfed Well watered Rainfed

Crosses MP BP MP BP MP BP MP BP MP BP MP BP

P1 • P2 -8.04 -19.61** 6.09 -8.99 7.18 4.94 0.49 -1.62 -21.93** -27.81** -24.44** -32.00**

P1 X P3 -20.05** -25.00** -10.17 -17.87** -7.99 -13.67 -13.74 -19.06** -39.53** -43.48** -27.38** -35.00**

P1 X P4 35.33** 12.25 33.02** 17.11** 3.07 2.28 -3.38 -4.11 -60.98** -61.90** -52.65** -60.00**

P1 X P5 -23.77** -34.28** -23.28** -31.44** 14.67 14.45 7.50 7.30 -9.09 -25.00** -10.06 -25.80**

P1 X P6 5.66 -7.75 15.26 -3.76 -7.17 -12.20 -7.32 -10.71 -17.80** -20.00** -25.07** -26.86**

P1 X P7 -6.49 -13.23 13.28 5.15 37.71** 21.88** 29.08** 19.96** -16.50** -24.85** -16.40** -24.76**

P2 X P3 20.64** 11.84 25.63** 0.07 0.29 -7.73 0.29 -7.73 -14.07 -15.07 -5.89 -23.20**

P2 X P4 4.23 -2.00 31.27** 27.39** 24.46** 22.78** 3.72 2.32 -41.64** -44.80** -39.67** -53.20**

P2 X P5 16.64 14.75 30.40** 24.46** 8.48 6.41 -9.60 -11.32 -1.50 -23.57** -14.74 -35.20**

P2 X P6 -13.59** -12.28 -2.77 -5.88 5.20 -2.47 -10.50 -15.50** -32.49** -39.11** -45.22** -49.60**

P2 X P7 -25.95** -39.26** -21.38** -36.60** 18.10** 15.63** 6.08 0.57 -21.57** -34.14** -17.56** -32.40**

P3 X P4 -4.72 -16.54 -1.76 -19.91** 12.94 5.23 -5.88 -12.31 -27.27** -30.43** 8.14 1.24

P3 X P5 43.09** 30.67** 31.06** 8.30 9.32 2.40 -3.63 -9.73 -27.78** -43.48** -9.73 -17.74**

P3 X P6 - 2.89 -10.09 -12.41 -31.89** 10.66 9.73 12.79 9.73 -16.00 -23.43** -2.18 -14.29

P3 X P7 -28.10** -37.09b -35.41** -36.46** 8.42 1.73 16.08** 1.73 -20.92** -32.96** 10.93 10.25

P4 X P5 59.08** 51.91** 87.79** 84.61** 17.16** 16.49 9.84 9.21 -11.76 -28.57** 29.01** 25.33**

P4 X P6 - 8.33 -13.70 2.76 -3.38 -1.59 -7.59 -16.29** -19.94** -19.86** -23.81** -11.69 -26.86**

P4 X P7 -1.05 -22.62** -2.18 -19.23** -8.51 -9.20 -17.91** -23.17** -1.62 -13.33 15.62 7.63

P5 X P6 35.14** 33.13** 42.24** 31.63** 8.04 1.99 -8.12 -11.64 37.55** 16.01** 33.41** 8.00

P5 X P7 1.50 -17.80 2.49 -14.19 5.25 5.05 -5.61 -12.12 31.79** 19.44** 35.56** 22.85**

P6 X P7 -24.92** -38.48** -18.39** -35.79** 0.93 -4.54 -7.90 -17.30** -10.33 -17.27** -14.77 -24.91**

Characters Number of pods per plant 100 seed weight (g) Seed yield per plant (g)

Well watered Rainfed Well watered Rainfed Well watered Rainfed

Crosses MP BP MP BP MP BP MP BP MP BP MP BP

P1 X P2 -28.75** -37.77** -35.18** -38.46** -4.40 -7.23 -4.81 -15.27 -20.02** -27.93** -16.69** -24.93**

P1 X P3 -34.75** -36.11** -47.09** -47.50** -24.21** -26.05** -21.40** -23.31** -49.29** -56.18** -51.46** -58.05**

P1 X P4 -14.41 -19.74 -26.21** -27.67** -31.37** -35.90** -23.75** -28.78** 13.65 0.86 -5.85 -16.82**

P1 X P5 36.75** 26.04** 82.25** 48.74** -1.98 -6.72 8.91 3.65 21.30** 15.42 1.44 -3.81

P1 X P6 21.62** 18.42 22.60** 19.83 1.34 -1.96 8.88 5.33 -26.41** -33.10** -37.57** -44.25**

P1 X P7 27.86** 8.33 44.88** 3.85 -5.35 -9.83 -5.35 -9.83 58.32** 31.31** 33.29** 9.42*

P2 X P3 23.08** 5.58 29.27** 21.81 -9.93 -10.43 -1.58 -10.43 -9.09 -13.27 -21.92** -25.50**

P2 X P4 35.46** 25.49** 49.58** 44.79** -5.79 -14.43 4.46 -12.41 3.20 1.45 2.65 0.40

P2 X P5 29.82** 5.79 48.27** 16.26 9.49 7.32 24.38** 15.89 54.62** 33.32** 55.11** 33.32**

P2 X P6 40.17** 25.33** 50.47** 39.80** -15.66 -15.93 -4.35 -12.26 64.17** 35.96** 66.79** 35.96**

P2 X P7 50.24** 14.08 89.42** 31.62** -14.93 -16.54 -4.50 -11.10 13.66 -13.14 11.49 -15.55

P3 X P4 64.85** 51.59** 87.98** 82.83** -8.16 -16.17 -8.16 -16.17 -22.57** -24.89** -25.10** -26.98**

P3 X P5 78.86** 68.13** 66.34** 36.59** -0.62 -3.12 -0.62 -3.12 -22.39** -35.67** -24.33** -37.45**

P3 X P6 63.86** 56.32** 63.14** 60.70** -24.30** -24.96** -24.30** -24.96** 1.92 -18.66 3.45 -18.66**

P3 X P7 25.70** 8.41 40.47** 1.18 -19.80 -21.74** -19.80** -21.74** -36.93** -53.33** -36.40** -53.33**

P4 X P5 44.67** 25.74** 64.52** 32.20** -3.66 -14.06 -3.66 -14.06 19.38** 1.47 23.97** 4.60

P4 X P6 43.08** 37.66** 51.01** 44.73** -5.66 -14.56 -3.40 -12.51 40.34** 14.66 47.50** 18.20**

P4 X P7 120.55** 77.34** 84.32** 30.54** -28.78** -36.41** -26.15** -34.06** -0.13 -24.57** 4.21 -22.24**

P5 X P6 24.63** 12.11 42.95** 18.80 -22.97** -24.26** -20.11** -21.45** 63.43** 55.75** 74.19** 63.45**

P5 X P7 51.29** 37.94** 47.33** 24.20** -1.03 -1.13 1.42 1.31 96.97** 70.32** 94.58** 66.96**

P6 X P7 81.75** 50.67** 78.94** 30.11** 4.45 2.80 -19.34** -20.62** 57.57** 42.22** 50.07** 36.33**

"'Significance at P 6 0.05 and 0.01 probability level, respectively.

genetic divergence among the parents assessed, resulting in a favorable situation for breeding. Moreover, various cross combinations exhibited different degrees of Fi superiority in some traits based on the genes in parental combinations that may contribute directly or indirectly to the characters. Many investigators proposed that favorable heterosis varied according to the cross combinations for different traits (Abdelmula et al., 1999; Link et al., 1999, 2010; Abdalla et al., 2001; Attia et al., 2002; Omar, 2004; Darwish et al., 2005; Attia and Salem,

2006; El-Hady et al., 2006; Ghaouti and Link, 2009; Hossam, 2010).

Combining ability

Analysis of variance for combining ability is presented in Table 6. Mean squares of both GCA and SCA were highly significant or significant in both generations for all the studied traits under well watered and rainfed conditions. Moreover,

Table 6 Mean squares of general (GCA) and specific (SCA) combining ability in faba bean crosses in F1 and F2 generations for

different studied traits under well watered and rainfed treatments.

Characters Days to 50% flowering Plant height (cm) Number of branches per plant

Well watered Rainfed Well watered Rainfed Well watered Rainfed

SV d.f. Fi F 2 F1 F2 F1 F2 F1 F2 F1 F2 F1 F2

Genotype 27 329.60** 248.55** 278.42** 241.75** 279.74** 274.03** 259.05** 175.38** 6.00** 5.06** 3.55** 3.25**

GCA 6 56.70* 64.52* 311.73** 143.95** 231.54** 204.01** 220.16** 130.56** 11.83** 5.30** 2.99** 5.17**

SCA 21 407.57** 301.13** 268.90** 282.98** 293.51** 294.04** 270.16** 188.18** 4.33** 4.99** 3.71** 2.71**

Error 54 34.37 38.16 31.80 29.80 153.92 125.46 77.31 80.29 3.12 2.61 2.04 3.12

GCA/SCA 0.14 0.21 1.16 0.51 0.79 0.69 0.81 0.69 2.73 1.06 0.81 1.90

Characters Number of pods per plant 100 seed weight (g) Seed yield per plant (g)

Well watered Rainfed Well watered Rainfed Well watered Rainfed

SV d.f. F1 F 2 F1 F2 F1 F2 F1 F2 F1 F2 F1 F2

Genotype 27 537.27** 1254.07** 338.71** 756.01** 354.64** 379.23** 141.05** 182.63** 911.45** 573.64** 638.56** 387.81**

GCA 6 969.27** 1855.53** 304.36* 1125.67** 209.37** 494.97** 160.63** 208.24** 1053.03** 395.39** 927.08** 323.90**

SCA 21 413.84** 1082.23** 348.52** 650.39** 267.57** 346.16** 135.46** 175.31** 870.99** 624.56** 556.12** 406.07**

Error 54 201.59 282.02 122.36 171.56 8.26 6.98 5.73 4.69 311.54 214.25 188.53 136.82

GCA/SCA 2.34 1.71 0.87 1.73 0.78 1.43 1.19 1.19 1.21 0.63 1.67 0.80

"'Significance at P 6 0.05 and 0.01 probability level, respectively.

Table 7 Estimates of general combining ability effects for the studied traits under well watered and rainfed conditions in F 1 and F2

generations.

Characters Days to 50% flowering Plant height (cm) Number of branches per plant

Parents Well watered Rainfed Well watered Rainfed Well watered Rainfed

F1 F2 F1 F2 F1 F2 F1 F2 F1 F2 F1 F2

P1 (G.461) 0.790 -0.014 1.820** 1.065* -5.138** -4.813** 2.152* -3.850** 0.558** 0.593** -0.466** 0.727**

P2 (NBL2) 0.077 0.819 -3.261** -0.212 -0.916 1.685 -2.714** 1.348 -0.628** 0.018 0.264* 0.326

P3 (L 82009- 3) -1.977* -1.308* 4.070** 0.343 0.204 1.012 4.925** 0.810 -0.035 0.326 0.129 0.122

P4 (Aquadulce) -1.183* 1.766** 0.414 -3.619** 4.564** -2.770* -3.292** -2.216* -0.776** 0.210 -0.343* -0.274

P5 (NBL4) 2.294** -2.002** 1.845** -1.970** -0.924 1.458 -1.341 1.167 -0.546** -0.630** -0.184 -0.492**

P6 (L5) -0.837 1.879** -5.853** 0.771 0.956 2.861* 0.096 2.289* 0.765** 0.015 0.421** 0.017

P7 (L8) 0.836 -1.140 0.964 3.622** 1.254 0.566 0.174 0.453 0.661** -0.531** 0.180 -0.426**

SE a2gi 1.045 1.101 1.005 0.973 2.211 1.996 1.567 1.597 0.315 0.288 0.254 0.231

SE a2gi/ a2si 1.596 1.681 1.535 1.486 3.377 3.048 2.393 2.439 0.481 0.440 0.389 0.353

Characters Number of pods per plant 100 seed weight (g) Seed yield per plant (g)

Parents Well watered Rainfed Well watered Rainfed Well watered Rainfed

F1 F2 F1 F2 F1 F2 F1 F2 F1 F2 F1 F2

P1 (G.461) -9.910** -13.058** -6.000** -10.056** 0.587 6.165** 1.441** 3.701** -7.245** -3.193* -8.680** -4.980**

P2 (NBL2) -7.169** 11.076** 2.505* 8.857** 0.699 -0.160 0.305 -0.369* 7.753** 4.973** 6.162** 4.326**

P3 (L 82009- 3) 2.898* -6.924** -0.868 -5.180** -2.921** -2.705** -2.978** -2.256** -5.546** -0.365 -4.910** 0.042

P4 (Aquadulce) 2.846* 6.226** 1.843* 5.064** 5.024** 5.287** 3.870** 3.643** 5.583** 5.557** 4.921** 4.363**

P5 (NBL4) 4.194** -1.343 -1.290 -1.096 0.990* -0.148 1.075** 0.492 4.921** -2.025 4.904** -1.266

P6 (L5) 1.807 5.370** 4.384** 3.851** -1.370** -3.487** -0.954** -2.246** 0.455 -0.804 1.757 0.298

P7 (L8) 5.333** -1.348 -0.574 -1.440 -3.010** -4.951** -2.759** -2.965** -5.921** -4.145** -4.153** -2.783*

SE a2gi 2.530 2.992 1.971 2.334 0.512 0.471 0.427 0.386 3.145 2.608 2.446 2.0848

SE a2gi/ a2si 3.864 4.571 3.011 3.565 0.782 0.719 0.651 0.589 4.804 3.984 3.737 3.184

*,**Significance at P 6 0.05 and 0.01 probability level, respectively.

the variances due to GCA were larger than those for SCA and the ratio of r2GCA/r2 SCA exceeded the unity for days to 50% flowering in Fi generation under rainfed conditions, no. of branches per plant, no. of pods per plant in both treatments and generations except for the Fi generation under rainfed conditions, 100-seed weight in both treatments and generations

except for the Fi generation under well watered conditions and seed yield per plant in both treatments and generations except for F2 generation under well watered and rainfed conditions, revealing that the largest part of the total genetic variance associated with different traits being the result of additives types on gene action. This indicated that direct selection could be

Table 8 Estimates of specific combining ability effects for the studied traits under well watered and rainfed conditions in F1 and F2

generations

Characters Days to 50% flowering Plant height (cm) Number of branches per plant

Well watered Rainfed Well watered Rainfed Well watered Rainfed

Crosses Fi F2 Fi F2 Fi F2 Fi F2 Fi F2 Fi F2

P1 x P2 -7.475** ii.377** —0.855 8.7i0** —5.60i 3.388 — i.i6i 2.7ii 2.405** 0.406 0.ii0 0.i46

Pi X P3 2.779 — i3.i94** —4.452 —13.737** 9.279* —0.672 —13.049** —0.538 i.i47* 0.685 —0.867* 0.690

Pi X P4 — ii.948** —9.708** 7.500** —4.396* —8.748* ii.ii0** —2.333 8.888** i.220* —0.080 —1.784** 0.296

Pi X P5 — ii.244** —4.4i2 —16.308** i.7i3 —2.26i 3.0i5 3.7i6 2.4i2** —i.676** 0.448 —0.042 0.274

Pi X P6 —6.695** —3.694 4.i48 3.388 6.859* —i7.i88** —5.404* —13.750** —0.320 — i.35i** —0.502 —i.i75**

Pi X P7 i8.693** 0.885 9.56i** 0.020 —4.i05 —4.493 28.0i9** —3.594 —1.884** —0.i98 —0.26i —0.08i

P2 X P3 —4.602 i5.007** i0.608** i4.7i8** —8.6i0* 9.990** 0.880 7.992** —1.002** —1.087* 0.i26 —0.7i8*

P2 X P4 i8.488** —9.097** 3.273 0.383 —9.636** i.279 5.95i* i.023 —1.927 —0.678 —i.485** —0.073

P2 X P5 —14.823** —8.438** 2.347 —2.72i 6.5i7* i5.984** —4.7i2* i2.787** 0.i76 — i.6i7** —0.394 —1.325**

P2 X P6 5.3i8 i.980 —4.079 i0.9ii** —9.363* 0.i68 —4.i67 0.i34 —0.802 —1.656** —0.999** —1.344**

P2 X P7 9.498** —18.869** —7.823** — i7.2i3** 30.339** —2.324 —0.60i —1.859 —0.698 —1.090* —0.564 —0.90i**

P3 X P4 —4.407 —6.042** -4.i84 i.583 5.577 -i3.5i5** -2.204 -i0.8i2** -0.854 -i.573** -0.i57 -0.358

P3 X P5 0.i52 2.409 i0.074** i.954 -2.003 -8.543* -2.093 -6.835* 0.583 0.42i -i.i48 0.829**

P3 X P6 -i0.37i** -3.206 -4.579** -7.2i8** —0.909 —6.079* i2.044** —4.864 —0.728 —0.204 —0.364 0.32i

P3 X P7 —7.947** —12.836** —13.936** —19.557** 4.259 i2.6i5** 5.566* i0.092** —0.624 —1.398** —0.223 —0.696*

P4 X P5 i7.7i0** —8.6i9** 20.50i** —5.i8i** 3.i04 5.506 i0.2i3** 4.404 —0.343 i.i23** 0.5i3 0.695*

P4 X P6 —2.059 —2.723 —4.924 —0.589 8.557* 4.009 —6.948** 3.208 0.0i3 —0.969* —0.625 —0.794*

P4 X P7 —7.ii8** 5.623** —2.i50 ii.202** 0.259 —2.389 —14.537** — i.9ii 0.ii7 —0.i09 0.i32 —0.i60

P5 X P6 —14.752** —2.388 7.538** 4.258** —4.82i 7.648* —2.6i6 6.ii8** —0.884 —0.i48 i.250** —0.576

P5 x P7 0.245 6.768** —0.872 7.ii3** —16.386** —2.697 —8.i60** —2.i58 —0.046 —0.462 i.490** —0.723*

P6 X P7 6.988** 6.972** —4.795 8.i72** —5.773 i5.967** —8.4i4** i2.773** 0.976* i.260** 0.885* 0.338

SE a2slJ 3.038 3.20i 2.922 2.829 6.429 5.804 4.556 4.643 0.9i5 0.837 0.740 0.672

SE a2gi/a2si 4.5i3 4.755 4.34i 4.202 9.550 8.622 6.769 6.898 i.360 i.244 i.099 0.998

Characters Number of pods per plant i00 seed weight (g) Seed yield per plant (g)

Well watered Rainfed Well watered Rainfed Well watered Rainfed

Crosses Fi F2 Fi F2 Fi F2 Fi F2 Fi F2 Fi F2

Pi X P2 i0.055* —8.622 —8.632 —7.i37 i.457 4.709** —0.788 3.666** —13.947 —16.642** —5.684 —16.235**

Pi X P3 —3.0ii —10.609 —8.370 —8.646 —10.540** —1.688 —7.5i2** — i.i54 —17.390** —22.52i** —i0.853** —19.430**

Pi X P4 —1.627 —14.359** —6.636 — ii.579** —18.568** —3.220* — ii.02i** —2.208 i0.956* —1.994 2.268 —6.ii8

Pi X P5 — ii.64i** i3.577** i0.793** i0.422* i.596 3.948** 5.2i6** 2.243 3.309 0.020 —3.255 —2.3i0

Pi X P6 0.4i2 —2.850 —0.5i2 —2.080 7.903** —2.428 8.29i** —2.306 —i9.590** — ii.236 — i8.35i** —7.979

Pi X P7 —15.780** 0.i08 i.336 0.287 3.009* —6.452** 0.658 —5.703** 23.i08** 24.432** ii.774** 20.964**

P2 X P3 —i3.4i9** 4.4i3 —0.704 2.896 —1.308 —5.83i** —1.073 —3.284 0.830 6.34i —5.539 3.9i7

P2 X P4 —6.700 25.742** i.562 i9.469** i.850 —4.496** i.857 —1.930 —3.6i4 6.368 —2.445 4.357

P2 X P5 i0.285 i2.866 7.547 9.727 7.854** 2.594 7.005** 2.509 i6.946** — i.i44 i3.490** 0.i23

P2 X P6 2.338 32.73i** i6.703** 25.452** —7.936** —9.3i4** —5.083** —7.599** 23.272** — i.36i i8.i25** 2.780

P2 X P7 —5.i88 2.647 i.i28 2.i20 —6.773** —8.250** —4.240** —7.725** —4.870 —16.659** —4.936 — ii.084**

P3 X P4 i.566 6.767 i0.639** 4.748 3.8i0* —3.346* 2.444 —2.998 —5.997 —22.600** —5.2i2 — i5.38i**

P3 X P5 3.885 i0.200 i0.350** 7.69i 4.i74** —0.993 2.487 —0.374 —i3.679 — i3.05i** — ii.685 —7.962

P3 X P6 25.339** 0.039 i.824 0.063 —10.706** —i2.i36** —8.4i4** —8.899** 3.950 5.306 3.099 4.i89

P3 X P7 —4.587 —7.030 —4.625 —5.369 —6.526** —8.538** —4.704** —6.522** —i6.509** — i2.i43** —i2.458** —9.983*

P4 X P5 3.204 4.427 0.794 3.i84 i.9i9 —4.205** —0.095 —3.794* —0.769 —2.868 i.283 —1.389

P4 X P6 i.923 2.266 —2.339 i.778 3.800* —1.270 3.042* —2.038 i3.296s 2.344 i2.43i** 2.406

P4 X P7 —16.270** 28.872** i3.7i5** 22.538** — i5.46i** —17.362** —10.607** — ii.667** —8.875 —6.952 —5.450 —5.043

P5 X P6 —1.292 —3.i75 —6.466 —2.i8i — i5.i04** —i5.i02** — ii.20i** —9.223** 9.839* —3.i46 9.0i4* —4.286

P5 X P7 9.449 2.873 —1.880 2.589 2.056 —0.60i i.987 2.359 30.39i** 7.850 26.738** 4.920

P6 X P7 -i2.244** i9.280** 22.062** i5.624** 9.887** 7.333** 6.743** 8.926** 6.98i i0.2ii* 6.656 6.220*

SE a2sij 7.357 8.702 5.732 6.787 i.489 i.369 i.240 i.i22 9.i46 7.585 7.ii5 6.06i

SE a2gi/a2si i0.930 i2.928 8.5i5 i0.082 2.2i2 2.034 i.843 i.667 i3.587 ii.268 i0.570 9.004

^"Significance at P 6 0.05 and 0.0i probability level, respectively.

useful for improving these traits. However, the rest of the cases gave low ratios (less than unity), revealing the predominance of non-additive gene action. It could be concluded that both additives and dominance of genetic components seemed to be important in controlling operating the inheritance of the

studied traits, although the contribution of each component varied according to trait, generation and irrigation treatment. These findings are in agreement with those of (Abdalla et al., 1999, 2001; El-Keredy et al., 1999; Attia et al., 2002; El-Hosary et al., 2002; Attia and Salem, 2006; Alghamdi, 2009; Hossam,

2010) who reported that both of additives and non additive gene effects were significant for most of the studied traits.

Comparisons between GCA effects (gi) associated with individual parents in each trait are illustrated in Table 7. Results revealed that the parent P2 (NBL2) in F1 generation under rainfed conditions, P3 in the two generations under well watered conditions, P4 (Aquadulce) in F1 and F2 generations under well watered and rainfed conditions, respectively, P5 (NBL4) in F2 generation under both treatments and P6 (L5) in F2 generation under rainfed conditions showed highly significant useful negative effects for days to 50% flowering. Whereas, P1 (G.461) and P3 (L 82009-3) in F1 generation under rainfed conditions, P4 (Aquadulce) in F1 generation under well watered conditions and P6 (L5) in F2 generation under both treatments had significant positive (gi) effects for plant height. Moreover, P1 (G.461) in both generations and the two treatments except for F1 generation under rainfed conditions, P2 (NBL2) in F1 generation under rainfed conditions, P3 (L 82009-3) under both treatments in F2 generation, P6 (L5) in F1 generation under both treatments and P7 (L8) in F1 generation under well watered treatment showed highly significant positive (gi) effects for number of branches per plant. For number of pods per plant, P4 (Aquadulce) in the two generations and treatments, P2 (NBL2) and P6 (L5) except in F1 generation under well watered treatment and the three parental genotypes P3 (L 82009-3), P5 (NBL4) and P7 (L8) in F1 generation under well watered conditions exhibited significant positive (gi) effects. However, P4 (Aquadulce) in both generations and treatments, P1 (G.461) except for F1 under well watered conditions and P5 (NBL4) in F1 generation under both treatments registered significant positive GCA effects for 100-seed weight. For seed yield per plant the two parents P2 (NBL2) and P4 (Aquadulce) in both generations as well as P5 (NBL4) in F1 generation under both treatments showed significant positive GCA effects. The all previous parents are considered to be good general combiners for their respective traits. Also results suggest that three parental genotypes; P1 (G.461), P2 (NBL2) and P4 (Aquadulce) are considered to be good combiners for improving most of the studied traits and could be exploited as genetic resources for faba bean yield improvement. Similar results were obtained by (Abdalla et al., 1999; El-Hosary et al., 2002; Darwish et al., 2005; Attia and Salem, 2006; El-Hady et al., 2006; Alghamdi, 2007; El-Harty et al., 2007; Alghamdi, 2009).

Specific combining ability effects of F1-cross combinations were computed for each cross in the F1 and F2 generations for the studied traits (Table 8). For number of days to 50% flowering nine and six crosses of F1 under well watered and rainfed conditions, respectively as well as eight and six crosses in F2 under well watered and rainfed conditions, respectively had highly significant desirable negative effects. Five F1-crosses (P1 x P3, P1 x P6, P2 x P5, P2 x P7 and P4 x P6) under well watered conditions and other five crosses (P1 x P7, P2 x P4, P3 x P6, P3 x P7 and P4 x P5) under rainfed conditions as well as six crosses (P1 x P4, P2 x P3, P2 x P5, P3 x P7, P5 x P6 and P6 x P7) in F2 under both treatments and the cross P1 x P5 under rainfed conditions exhibited significant positive SCA effects for plant height. Moreover, four crosses (P1 x P2, P1 x P3, P1 x P4 and P6 x P7) under well watered and three crosses (P5 x P6, P5 x P7 and P6 x P7) under rainfed conditions in F1 as well as the two crosses; P4 x P5 and P6 x P7 in F2 generation under well watered conditions and one cross (P4 x P5) under

rainfed conditions showed significant positive SCA effects for number of branches per plant. While, the four crosses; P1 x P5, P2 x P6, P4 x P7 and P6 x P7 in both generations under the two irrigation treatments except in F1 generation under well watered conditions, the two crosses (P1 x P2 and P3 x P6) and (P3 x P4 and P3 x P5) in F1 under well watered and rainfed conditions, respectively as well as the cross P2 x P4 in F2 under both treatments had significant positive SCA effects for number of pods per plant. The cross P6 x P7 in the two generations under both treatments along with the cross P1 x P2 in F2 generation under both treatments, P1 x P5 in F1 and F2 generations under well watered and rainfed conditions, respectively, P1 x P6, P2 x P5 and P4 x P6 in F1 under both treatments and the three crosses; P1 x P7, P3 x P4 and P3 x P5 in F1 generation under well watered conditions showed significant positive SCA effects for 100-seed weight. Moreover, the seven crosses; P1 x P7 in both generations under the two treatments, P1 x P4 in F1 generation under well watered conditions, P2 x P5, P2 x P6, P4 x P6 and P5 x P7 in F1 generation under both treatments and P6 x P7 in F2 generation under rainfed conditions possessed significant positive SCA effects for seed yield per plant. Thus SCA effects for seed yield per plant seemed to be influenced by SCA effects for yield components. These results are in line with those reported by El-Hosary et al. (2002), Attia and Salem (2006), El-Hady etal. (2006), Alghamdi (2009) and Hossam (2010).

In general, the previous results showed that some yield components are more important for yield expression than others. In the selection program, however adjustments up to the desired levels of each component may have to be made in order to obtain the maximum seed yield potential. Abdalla et al. (1999) reported that crosses which showed high SCA effects, it might include only one good combiner, such combinations might have desirable transgressive segregations providing that the additive genetic.

system present in the crosses are acting in the same direction to reduce un-derisible plant characteristics and maximize the characters in view which is important in traditional breeding programs for environmental stresses. These results are in agreement with those reported by El-Keredy et al. (1999), Abdalla et al. (2001), Attia et al. (2002), Darwish et al. (2005), Attia and Salem (2006), El-Hady etal. (2006) and Hossam (2010).

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