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General and specific combining ability studies for leaf area in some maize inbreds in agroecological conditions of Kosovo

General and specific combining ability studies for leaf area in some maize inbreds in... In maize breeding one of the most important roles belongs to selection of parents with good combining abilities. The data associated with combining ability and heritability of particular characters can be obtained from diallels. The main objective of this study was to evaluate the leaf area (LA) of 10 inbred lines and their F1 hybrids. Based on a diallel (without reciprocals) GCA and SCA were calculated. The components of the genetic variance were calculated using Griffing's (1956) method 2. The maximum LA value was determined for the combination 2 2 L6×L10 (788.6 cm ), whereas the minimum for the combination L4×L5 (558.9 cm ). The 2 2 average value of F1 generation was 678.8 cm and the variation range was from +109.8 cm to 2 -119.9 cm . Both, the GCA and SCA for LA were significant at p=0.01. The highest value of GCA was obtained for L2 (+31.33), whereas the lowest for L4 (­38.07). The highest value of SCA was determined for L6×L10 (+156.73). Key words: Maize, inbred lines, GCA, SCA, leaf area. Abbreviations: LA, leaf area; GCA, general combining ability; SCA, specific combining ability; L, inbred line, F1 generation; MP, middle parents; EP, experimental plots; SE, standard error. IZVLEýEK PROUýEVANJE SPLOSNE IN POSEBNE KOMBINACIJSKE SPOSOBNOSTI LISTNE POVRSINE NEKATERIH SAMOOPLODNIH LINIJ KORUZE V AGROEKOLOSKIH RAZMERAH KOSOVA V zlahtnjenju rastlin igra eno od najpomembnejsih vlog selekcija roditeljev z dobrimi kombinacijskimi sposobnostmi za zelene lastnosti, ki jih obiþajno ugotavljamo z dialelnimi krizanji. Namen raziskave je bil ugotoviti kombinacijsko sposobnost 10 samooplodnih linij koruze ter njihovih krizancev za listno povrsino (LP). Na osnovi njihovih dialelnih krizancev (brez reciproþnih krizancev) je bila za LP izraþunana splosna (SKS) in posebna (PKS) kombinacijska sposobnost. Komponente genetske variabilnosti so bile raþunane po metodi 2 Griffingovega modela (1956) raþunanja kombinacijskih sposobnosti. Najveþja LP je bila University of Prishtina, Faculty of Agriculture, Kosova University of Ljubljana, Biotechnical Faculty, Slovenia, e-mail: ludvik.rozman@bf.uni-lj.si University of Tirana, Faculty of Agriculture, Albania 68 Acta agriculturae Slovenica, 91 - 1, maj 2008 ugotovljena za krizanec L6×L10, (788,6 cm ), najmanjsa pa za krizanec L4×L5 (558,9 cm ), 2 medtem ko je bila povpreþna vrednost vseh krizancev 678,8 cm . Tako za SKS kot za PKS so bile ugotovljene statistiþno znaþilne razlike med krizanci pri p=0,01. Najveþja vrednost SKS za LP je bila ugotovljena pri L2 (+31,33), najnizja pa pri L4 (­38,07), medtem ko je bila najveþja vrednost PKS ugotovljena za krizanec L6×L10 (+156,73). Kljuþne besede: koruza, samooplodne linije, splosna kombinacijska sposobnost, posebna kombinacijska sposobnost, listna povrsina. 1 INTRODUCTION The leaf area is a one of the crucial factors in photosynthesis. It is especially important for maize (Sylvester et al., 1990). LA is closely associated with the transpiration process and other physiological characteristics of maize genotypes. Very important are also environmental factors and their interactions with plant characteristics and cultural practice. In the literature, it is possible to find many researches in this field. Jevtiü (1977) in his investigation found that the total surfaces of leaves/plant varied from 0.3-1.2 m2. Niþiporoviü (1961), and Gotlin and Pucariü, (2000) concluded that level of the absorbed energy gets higher with increasing of LA with value 25.000 m2/ha. Toming (1977), according to the data of Lapþeviü (1985), found out that participation of assimilated LA of maize more than 40-50.000 m2/ha did not have any effect for increasing of using energy. In some maize inbred lines Aliu (2003, 2006) obtained average maximal and minimal values of LA 0.56-0.75 m2, while Salillari et al., (2002) and Jakovljeviü (1989) at some inbred lines for LA obtained different values from 0.40-0.80 m2 and 0.79 m2, respectively. The present investigation was undertaken to characterize ten diverse lines and their 45 F1 hybrid combinations for their general (GCA) and specific (SCA) combining ability, and to identify leaf area (LA). 2 MATERIALS AND METHODS Plant materials used as parents for crosses in this study were 10 selected superior maize inbred lines (L1, L2, ...L10) with medium maturity, originating from the Agriculture University of Tirana, Albania. Crosses among these inbred lines were based on a diallel. During the first 3 years, we evaluated adaptability of inbred lines to specific agro-ecological conditions of Kosovo, especially in the area near Ferizaj (580 m a.s.l). In the fourth year, we conducted diallel crosses (with 10 inbreds) following the method of Griffing (1956). The field experiments with F1 hybrids and their parents (10 diverse maize lines and their 45 F1 crosses) were conducted during the fifth year. The experiments were based on a randomized complete block design (RCBD) with three replications. The spacing was 60×30 cm or 55.000 plants per ha, 2 experimental plots was 5.4 m per each replications. The seeds were placed 3-5 cm deep. In order to determine LA we measured dimensions of the leaf blade growing from the same node as the ear. We measured 10 plants per replication; altogether 30 plants per combination. LA was determined according to the formula of Montgomery (1911): A = L×W×0.75, where L represents leaf length, W is leaf width and 0.75 is the factor used for determination of leaf area in maize. The same formula was also used by several other researchers such as Francis et al., (1969); Whigham et al., (1974) and Pearce et al., (1975). Genetic interpretations and analyses of similar experiments can be found in numerous papers such as Hayman (1954) and Griffing (1956). ALIU, S. in sod.: General and specific combining ability studies for leaf area in some ...69 Statistical analyses Differences among observed individuals, within each combination, were analysed using the mathematic model of Griffing (1956): Xij = µ+gi+gj+sij+e, th th Xij ­ value of the progeny derived from the crossing of i- female parent with j- male parent µ ­ grand mean, th gi ­ the GCA effects of the i- female parent, th gj ­ the GCA effects of the j- male parent, th th sij ­ the SCA effects specific to the hybrid of the i- female line and the j- male line, e ­ experimental error. ANOVA for GCA and SCA was calculated as presented in table 1. Table 1: Model of ANOVA for GCA and SCA according to Griffing's method 2 (Varghese et al., 1976). Source d.f. GCA n-1 S.S. SCA n(n 1) 2 1 ª n2« ¬ ¦ y 2 ij i. y ii 2 4 2º y.. n » ¼ i. ¦¦ y 1 n2 ¦(y y ii ) 2 2 2 y.. (n 1)(n 2) Error * ª n(n 1) º 1» u (r 1) Total S.S. Treatm. S.S. Replic. S.S. « 2 ¬ ¼ r - S.S. out of base ANOVA. Statistical analyses package were conducted using program ­ MSTAT-C , version 2.10 (Russell, 1996). 3 RESULTS AND DISCUSSION The calculations showed that the hybrid combination L6×L10 was characterised by the largest leaf area (788.6 cm2), while the smallest value was obtained for hybrid L4×L5, (558.9 cm2) (Table 2). The average value of LA for all studied genotypes was 678.8 cm2. The variation range between largest leaf area and smallest leaf area was 229.7 cm2 or 35%, and this difference was significant at p=0.05 and p=0.01. All F1 hybrids had positive heterosis; the highest value was 48% above the mid parent value (data not shown). The coefficient of variation of the total LA for all genotypes was 3.33%, while SE = ±21.3. The highest variability of LA values are obtained for hybrids L6×L10, (96%) and L3×L4, (19%). These difference of LA among F1 generation were statistically significant at p=0.05 and p=0.01. The heterosis of LA is one of the commonest and most striking manifestations of hybrid vigour (Evans, 1993). Kojiü (1982) obtained positive heterosis effect comparing with parents from 27.7-85.9%, while Bocanski (1995) found out that the inheritance of LA could be explained by over-dominance. Earlier genotypes developed smaller LA and they were below the mean value, while the genotypes 70 Acta agriculturae Slovenica, 91 - 1, maj 2008 with longer vegetation period had higher LA and were above mean value. Difference between the mean of all F1 hybrids and the mean of all parents (F1-MP) was 221.45 cm2. This could be considered as a result of heterosis of F1 generations. Table 2: Leaf area of parents (diagonal, underlined) and their F1 hybrids (above diagonal). L1 L1 489.0 L2 L3 L4 L5 L6 L7 L8 L9 L10 Grand mean L2 625.6 467.4 L3 681.8 737.9 472.8 L4 715.9 726.8 562.8 470.4 L5 752.7 744.9 647.6 558.9 440.3 L6 721.7 757.3 683.6 621.5 626.7 392.6 L7 580.6 723.1 733.8 626.6 685.8 709.4 463,0 L8 617.2 741.4 726,0 620.4 703.6 712.3 728.0 477.0 L9 662.6 761.2 730,6 593.5 583.2 682.0 684.9 702.8 490.0 L10 643.9 652,0 757,8 605.2 597.9 788.6 681.2 717.8 628.5 412.0 F1 Mean 666,89 718,91 695,77 625,73 655,70 700,34 683,71 687,60 669,92 674,77 677.93 LSD p=0.05 =42.69, p=0.01 =56.20. The statistical analysis of combining ability indicates that there are significant differences among genotypes in both, GCA and SCA (Tab.3). Non-additive effects of genes have important influence in LA inheritance. The ratio between GCA and SCA was 0.40. A similar ratio (0.36) was obtained by Kojiü (1982). Rutger et al. (1971) found that besides non-additive effects, an important role belonged also to additive variance, what was later confirmed also by Mason and Zuber (1976). As reported by Rojas and Sprague (1952), GCA is primarily associated with additive effects, whereas SCA is attributed to the non-additive genetic effects. Table 3: ANOVA of GCA and SCA for leaf area. Source GCA SCA SE d.f. 9 45 108 S.S. 125598.06 1572243.67 49076.53 M.S. 13955.34 34938.75 454.41 F-Value 30.71** 76.89** ** - Significant at p=0.01 The GCA effects for LA showed significant variation between hybrid combination of parental lines. The highest GCA effect for LA was observed for L2 (+31.33) (Tab. 4), with significant differences based on value F, suggesting the dominant gene action regarding LA in F1. The lowest GCA value was denoted by L4 (38.07). Large proportion between value F and differences among inbred lines for GCA were significant at p=0.05 and p=0.01 and have different intensity for heritage and variability. Kojiü (1982) obtained for LA maximal and minimal values of GCA between +42.971 and -31.314. Malik et al., (2004) published similar results for LA, GCA and SCA, using different genotypes, and obtained values between +41.32 and -20.27. ALIU, S. in sod.: General and specific combining ability studies for leaf area in some ...71 Table 4: GCA effects for LA (cm2) in F1 generation. Rank Parent GCA 1 L2 31.33 2 L8 16.15 3 L3 13.68 4 L7 6.71 5 L6 3.90 6 L9 -0.47 7 L1 -1.56 8 L10 -11.02 9 L5 -20.64 10 L4 -38.07 LSDp=0.05 = 17.22 SE(gi) =11.3603 LSDp=0.01 = 22.70 Table 5: Specific combining ability (SCA) for leaf area in a diallel among 10 maize inbreds. Rank 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Genotypes L6×L10 L1×L5 L1×L4 L3×L10 L2×L5 L2×L4 L2×L9 L2×L6 L1×L6 L3×L9 L3×L7 L8×L10 L5×L8 L7×L8 L5×L7 L6×L7 L3×L8 L2×L8 L2×L3 L6×L8 L8×L9 L7×L10 L2×L7 LSDp=0,05 LSDp=0,01 SE SCA 156,73 135,88 116,51 116,09 95,16 94,49 91,35 83,08 80,30 78,36 74,36 73,65 69,07 66,09 60,55 59,80 55,19 54,94 53,84 53,20 48,10 46,46 46,08 54,46 71,80 128,52 Homog. groups a* ab abc abc bcd bcd bcde bcdef cdef cdefg cdefg cdefg cdefgh cdefgh defgh defghi defghi defghi defghi defghi defghij defghijk defghijk Rank 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Genotypes L7×L9 L6×L9 L1×L3 L1×L9 L4×L7 L1×L10 L4×L6 L3×L5 L4×L10 L3×L6 L5×L6 L4×L8 L9×L10 L4×L9 L2×L10 L5×L10 L4×L5 L1×L7 L5×L9 L1×L8 L1×L2 L3×L4 LSDp=0,05 LSDp=0,01 SE SCA 39,60 39,58 30,62 25,57 18,97 17,50 16,65 15,50 15,24 14,96 4,42 3,34 1,00 -6,94 -7,32 -9,48 -21,50 -33,10 -34,70 -36,40 -43,10 -51,79 54,46 71,80 128,52 Homog. groups efghijkl efghijkl fghijklm ghijklm hijklmn hijklmno hijklmno hijklmno hijklmno hijklmno iiklmnop ijklmnop ijklmnopq jklmnopq kKlmnopq lmnopq mnopq mnopq nopq opq pq q * - the same letter indicate the same homogenous group. The highest values of SCA was obtained for the hybrid L6×L10 (+156.73). This value was also significant for three other hybrids (L1×L5, L1×L4, L3×L10) (Tab. 5). The lowest value of SCA was estimated for the hybrid L3×L4 (-51.79). The total differences for maximum values for phenotype variability were 208.52 in 72 Acta agriculturae Slovenica, 91 - 1, maj 2008 favour for genotype L6×L10, while in second place, there was the combination L1×L5 (+135.88), which was not significantly different from the hybrid L6×L10. The effect of SE for SCA of crossing parents was 128.52. Different results for SCA of LA with significant differences for maximal (+111.71) and minimal (-96.71) values were obtained by Kojiü (1982). 4 CONCLUSIONS Results of our investigations indicate that there were significantly different combining abilities for leaf area among investigated inbred lines. All F1 hybrids expressed positive heterosis effect (for leaf area) regarding to their parents. The highest value of LA was found for L6×L10, while the lowest value for L4×L5. It was not possible to prove the rule that inbreds with good GCA usually had the good SCA. Namely, the inbred L2 had expressed the highest GCA for the investigated trait, but 2 out of 9 hybrids of this inbred showed negative value of SCA. On the other side, the highest value of SCA was found for hybrid L6×L10, but parental inbreds showed very low (3.90 for L6) or negative (-11.02 for L10) SCA. The investigation suggests that the some of the studied inbreds represent a highly valuable genetic material that could be successively used for further breeding. 5 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Acta Agriculturae Slovenica de Gruyter

General and specific combining ability studies for leaf area in some maize inbreds in agroecological conditions of Kosovo

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Publisher
de Gruyter
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Copyright © 2008 by the
ISSN
1581-9175
eISSN
1854-1941
DOI
10.2478/v10014-008-0007-4
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Abstract

In maize breeding one of the most important roles belongs to selection of parents with good combining abilities. The data associated with combining ability and heritability of particular characters can be obtained from diallels. The main objective of this study was to evaluate the leaf area (LA) of 10 inbred lines and their F1 hybrids. Based on a diallel (without reciprocals) GCA and SCA were calculated. The components of the genetic variance were calculated using Griffing's (1956) method 2. The maximum LA value was determined for the combination 2 2 L6×L10 (788.6 cm ), whereas the minimum for the combination L4×L5 (558.9 cm ). The 2 2 average value of F1 generation was 678.8 cm and the variation range was from +109.8 cm to 2 -119.9 cm . Both, the GCA and SCA for LA were significant at p=0.01. The highest value of GCA was obtained for L2 (+31.33), whereas the lowest for L4 (­38.07). The highest value of SCA was determined for L6×L10 (+156.73). Key words: Maize, inbred lines, GCA, SCA, leaf area. Abbreviations: LA, leaf area; GCA, general combining ability; SCA, specific combining ability; L, inbred line, F1 generation; MP, middle parents; EP, experimental plots; SE, standard error. IZVLEýEK PROUýEVANJE SPLOSNE IN POSEBNE KOMBINACIJSKE SPOSOBNOSTI LISTNE POVRSINE NEKATERIH SAMOOPLODNIH LINIJ KORUZE V AGROEKOLOSKIH RAZMERAH KOSOVA V zlahtnjenju rastlin igra eno od najpomembnejsih vlog selekcija roditeljev z dobrimi kombinacijskimi sposobnostmi za zelene lastnosti, ki jih obiþajno ugotavljamo z dialelnimi krizanji. Namen raziskave je bil ugotoviti kombinacijsko sposobnost 10 samooplodnih linij koruze ter njihovih krizancev za listno povrsino (LP). Na osnovi njihovih dialelnih krizancev (brez reciproþnih krizancev) je bila za LP izraþunana splosna (SKS) in posebna (PKS) kombinacijska sposobnost. Komponente genetske variabilnosti so bile raþunane po metodi 2 Griffingovega modela (1956) raþunanja kombinacijskih sposobnosti. Najveþja LP je bila University of Prishtina, Faculty of Agriculture, Kosova University of Ljubljana, Biotechnical Faculty, Slovenia, e-mail: ludvik.rozman@bf.uni-lj.si University of Tirana, Faculty of Agriculture, Albania 68 Acta agriculturae Slovenica, 91 - 1, maj 2008 ugotovljena za krizanec L6×L10, (788,6 cm ), najmanjsa pa za krizanec L4×L5 (558,9 cm ), 2 medtem ko je bila povpreþna vrednost vseh krizancev 678,8 cm . Tako za SKS kot za PKS so bile ugotovljene statistiþno znaþilne razlike med krizanci pri p=0,01. Najveþja vrednost SKS za LP je bila ugotovljena pri L2 (+31,33), najnizja pa pri L4 (­38,07), medtem ko je bila najveþja vrednost PKS ugotovljena za krizanec L6×L10 (+156,73). Kljuþne besede: koruza, samooplodne linije, splosna kombinacijska sposobnost, posebna kombinacijska sposobnost, listna povrsina. 1 INTRODUCTION The leaf area is a one of the crucial factors in photosynthesis. It is especially important for maize (Sylvester et al., 1990). LA is closely associated with the transpiration process and other physiological characteristics of maize genotypes. Very important are also environmental factors and their interactions with plant characteristics and cultural practice. In the literature, it is possible to find many researches in this field. Jevtiü (1977) in his investigation found that the total surfaces of leaves/plant varied from 0.3-1.2 m2. Niþiporoviü (1961), and Gotlin and Pucariü, (2000) concluded that level of the absorbed energy gets higher with increasing of LA with value 25.000 m2/ha. Toming (1977), according to the data of Lapþeviü (1985), found out that participation of assimilated LA of maize more than 40-50.000 m2/ha did not have any effect for increasing of using energy. In some maize inbred lines Aliu (2003, 2006) obtained average maximal and minimal values of LA 0.56-0.75 m2, while Salillari et al., (2002) and Jakovljeviü (1989) at some inbred lines for LA obtained different values from 0.40-0.80 m2 and 0.79 m2, respectively. The present investigation was undertaken to characterize ten diverse lines and their 45 F1 hybrid combinations for their general (GCA) and specific (SCA) combining ability, and to identify leaf area (LA). 2 MATERIALS AND METHODS Plant materials used as parents for crosses in this study were 10 selected superior maize inbred lines (L1, L2, ...L10) with medium maturity, originating from the Agriculture University of Tirana, Albania. Crosses among these inbred lines were based on a diallel. During the first 3 years, we evaluated adaptability of inbred lines to specific agro-ecological conditions of Kosovo, especially in the area near Ferizaj (580 m a.s.l). In the fourth year, we conducted diallel crosses (with 10 inbreds) following the method of Griffing (1956). The field experiments with F1 hybrids and their parents (10 diverse maize lines and their 45 F1 crosses) were conducted during the fifth year. The experiments were based on a randomized complete block design (RCBD) with three replications. The spacing was 60×30 cm or 55.000 plants per ha, 2 experimental plots was 5.4 m per each replications. The seeds were placed 3-5 cm deep. In order to determine LA we measured dimensions of the leaf blade growing from the same node as the ear. We measured 10 plants per replication; altogether 30 plants per combination. LA was determined according to the formula of Montgomery (1911): A = L×W×0.75, where L represents leaf length, W is leaf width and 0.75 is the factor used for determination of leaf area in maize. The same formula was also used by several other researchers such as Francis et al., (1969); Whigham et al., (1974) and Pearce et al., (1975). Genetic interpretations and analyses of similar experiments can be found in numerous papers such as Hayman (1954) and Griffing (1956). ALIU, S. in sod.: General and specific combining ability studies for leaf area in some ...69 Statistical analyses Differences among observed individuals, within each combination, were analysed using the mathematic model of Griffing (1956): Xij = µ+gi+gj+sij+e, th th Xij ­ value of the progeny derived from the crossing of i- female parent with j- male parent µ ­ grand mean, th gi ­ the GCA effects of the i- female parent, th gj ­ the GCA effects of the j- male parent, th th sij ­ the SCA effects specific to the hybrid of the i- female line and the j- male line, e ­ experimental error. ANOVA for GCA and SCA was calculated as presented in table 1. Table 1: Model of ANOVA for GCA and SCA according to Griffing's method 2 (Varghese et al., 1976). Source d.f. GCA n-1 S.S. SCA n(n 1) 2 1 ª n2« ¬ ¦ y 2 ij i. y ii 2 4 2º y.. n » ¼ i. ¦¦ y 1 n2 ¦(y y ii ) 2 2 2 y.. (n 1)(n 2) Error * ª n(n 1) º 1» u (r 1) Total S.S. Treatm. S.S. Replic. S.S. « 2 ¬ ¼ r - S.S. out of base ANOVA. Statistical analyses package were conducted using program ­ MSTAT-C , version 2.10 (Russell, 1996). 3 RESULTS AND DISCUSSION The calculations showed that the hybrid combination L6×L10 was characterised by the largest leaf area (788.6 cm2), while the smallest value was obtained for hybrid L4×L5, (558.9 cm2) (Table 2). The average value of LA for all studied genotypes was 678.8 cm2. The variation range between largest leaf area and smallest leaf area was 229.7 cm2 or 35%, and this difference was significant at p=0.05 and p=0.01. All F1 hybrids had positive heterosis; the highest value was 48% above the mid parent value (data not shown). The coefficient of variation of the total LA for all genotypes was 3.33%, while SE = ±21.3. The highest variability of LA values are obtained for hybrids L6×L10, (96%) and L3×L4, (19%). These difference of LA among F1 generation were statistically significant at p=0.05 and p=0.01. The heterosis of LA is one of the commonest and most striking manifestations of hybrid vigour (Evans, 1993). Kojiü (1982) obtained positive heterosis effect comparing with parents from 27.7-85.9%, while Bocanski (1995) found out that the inheritance of LA could be explained by over-dominance. Earlier genotypes developed smaller LA and they were below the mean value, while the genotypes 70 Acta agriculturae Slovenica, 91 - 1, maj 2008 with longer vegetation period had higher LA and were above mean value. Difference between the mean of all F1 hybrids and the mean of all parents (F1-MP) was 221.45 cm2. This could be considered as a result of heterosis of F1 generations. Table 2: Leaf area of parents (diagonal, underlined) and their F1 hybrids (above diagonal). L1 L1 489.0 L2 L3 L4 L5 L6 L7 L8 L9 L10 Grand mean L2 625.6 467.4 L3 681.8 737.9 472.8 L4 715.9 726.8 562.8 470.4 L5 752.7 744.9 647.6 558.9 440.3 L6 721.7 757.3 683.6 621.5 626.7 392.6 L7 580.6 723.1 733.8 626.6 685.8 709.4 463,0 L8 617.2 741.4 726,0 620.4 703.6 712.3 728.0 477.0 L9 662.6 761.2 730,6 593.5 583.2 682.0 684.9 702.8 490.0 L10 643.9 652,0 757,8 605.2 597.9 788.6 681.2 717.8 628.5 412.0 F1 Mean 666,89 718,91 695,77 625,73 655,70 700,34 683,71 687,60 669,92 674,77 677.93 LSD p=0.05 =42.69, p=0.01 =56.20. The statistical analysis of combining ability indicates that there are significant differences among genotypes in both, GCA and SCA (Tab.3). Non-additive effects of genes have important influence in LA inheritance. The ratio between GCA and SCA was 0.40. A similar ratio (0.36) was obtained by Kojiü (1982). Rutger et al. (1971) found that besides non-additive effects, an important role belonged also to additive variance, what was later confirmed also by Mason and Zuber (1976). As reported by Rojas and Sprague (1952), GCA is primarily associated with additive effects, whereas SCA is attributed to the non-additive genetic effects. Table 3: ANOVA of GCA and SCA for leaf area. Source GCA SCA SE d.f. 9 45 108 S.S. 125598.06 1572243.67 49076.53 M.S. 13955.34 34938.75 454.41 F-Value 30.71** 76.89** ** - Significant at p=0.01 The GCA effects for LA showed significant variation between hybrid combination of parental lines. The highest GCA effect for LA was observed for L2 (+31.33) (Tab. 4), with significant differences based on value F, suggesting the dominant gene action regarding LA in F1. The lowest GCA value was denoted by L4 (38.07). Large proportion between value F and differences among inbred lines for GCA were significant at p=0.05 and p=0.01 and have different intensity for heritage and variability. Kojiü (1982) obtained for LA maximal and minimal values of GCA between +42.971 and -31.314. Malik et al., (2004) published similar results for LA, GCA and SCA, using different genotypes, and obtained values between +41.32 and -20.27. ALIU, S. in sod.: General and specific combining ability studies for leaf area in some ...71 Table 4: GCA effects for LA (cm2) in F1 generation. Rank Parent GCA 1 L2 31.33 2 L8 16.15 3 L3 13.68 4 L7 6.71 5 L6 3.90 6 L9 -0.47 7 L1 -1.56 8 L10 -11.02 9 L5 -20.64 10 L4 -38.07 LSDp=0.05 = 17.22 SE(gi) =11.3603 LSDp=0.01 = 22.70 Table 5: Specific combining ability (SCA) for leaf area in a diallel among 10 maize inbreds. Rank 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Genotypes L6×L10 L1×L5 L1×L4 L3×L10 L2×L5 L2×L4 L2×L9 L2×L6 L1×L6 L3×L9 L3×L7 L8×L10 L5×L8 L7×L8 L5×L7 L6×L7 L3×L8 L2×L8 L2×L3 L6×L8 L8×L9 L7×L10 L2×L7 LSDp=0,05 LSDp=0,01 SE SCA 156,73 135,88 116,51 116,09 95,16 94,49 91,35 83,08 80,30 78,36 74,36 73,65 69,07 66,09 60,55 59,80 55,19 54,94 53,84 53,20 48,10 46,46 46,08 54,46 71,80 128,52 Homog. groups a* ab abc abc bcd bcd bcde bcdef cdef cdefg cdefg cdefg cdefgh cdefgh defgh defghi defghi defghi defghi defghi defghij defghijk defghijk Rank 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Genotypes L7×L9 L6×L9 L1×L3 L1×L9 L4×L7 L1×L10 L4×L6 L3×L5 L4×L10 L3×L6 L5×L6 L4×L8 L9×L10 L4×L9 L2×L10 L5×L10 L4×L5 L1×L7 L5×L9 L1×L8 L1×L2 L3×L4 LSDp=0,05 LSDp=0,01 SE SCA 39,60 39,58 30,62 25,57 18,97 17,50 16,65 15,50 15,24 14,96 4,42 3,34 1,00 -6,94 -7,32 -9,48 -21,50 -33,10 -34,70 -36,40 -43,10 -51,79 54,46 71,80 128,52 Homog. groups efghijkl efghijkl fghijklm ghijklm hijklmn hijklmno hijklmno hijklmno hijklmno hijklmno iiklmnop ijklmnop ijklmnopq jklmnopq kKlmnopq lmnopq mnopq mnopq nopq opq pq q * - the same letter indicate the same homogenous group. The highest values of SCA was obtained for the hybrid L6×L10 (+156.73). This value was also significant for three other hybrids (L1×L5, L1×L4, L3×L10) (Tab. 5). The lowest value of SCA was estimated for the hybrid L3×L4 (-51.79). The total differences for maximum values for phenotype variability were 208.52 in 72 Acta agriculturae Slovenica, 91 - 1, maj 2008 favour for genotype L6×L10, while in second place, there was the combination L1×L5 (+135.88), which was not significantly different from the hybrid L6×L10. The effect of SE for SCA of crossing parents was 128.52. Different results for SCA of LA with significant differences for maximal (+111.71) and minimal (-96.71) values were obtained by Kojiü (1982). 4 CONCLUSIONS Results of our investigations indicate that there were significantly different combining abilities for leaf area among investigated inbred lines. All F1 hybrids expressed positive heterosis effect (for leaf area) regarding to their parents. The highest value of LA was found for L6×L10, while the lowest value for L4×L5. It was not possible to prove the rule that inbreds with good GCA usually had the good SCA. Namely, the inbred L2 had expressed the highest GCA for the investigated trait, but 2 out of 9 hybrids of this inbred showed negative value of SCA. On the other side, the highest value of SCA was found for hybrid L6×L10, but parental inbreds showed very low (3.90 for L6) or negative (-11.02 for L10) SCA. The investigation suggests that the some of the studied inbreds represent a highly valuable genetic material that could be successively used for further breeding. 5

Journal

Acta Agriculturae Slovenica – de Gruyter

Published: Jun 1, 2008

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