DOI: 10.2478/v10014-008-0007-4 Agrovoc descriptors: zea mays, maize, inbred lines, leaf area, f1 hybrids, crossbreds, genetic variation Agris category codes: F30 COBISS Code 1.01 General and specific combining ability studies for leaf area in some maize inbreds in agroecological conditions of Kosovo Sali ALIU1, Shukri FETAHU1, Ludvik ROZMAN2, Adem SALILLARI3 Received March 31, 2008; accepted May 5, 2008. Prispelo 31. marca 2008; sprejeto 5. maja 2008. 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 L6*L10 (788.6 cm2), whereas the minimum for the combination L4*L5 (558.9 cm2). The average value of Fi generation was 678.8 cm2 and the variation range was from +109.8 cm2 to -119.9 cm2. 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, Fi generation; MP, middle parents; EP, experimental plots; SE, standard error. IZVLEČEK PROUČEVANJE SPLOŠNE IN POSEBNE KOMBINACIJSKE SPOSOBNOSTI LISTNE POVRŠINE NEKATERIH SAMOOPLODNIH LINIJ KORUZE V AGROEKOLOŠKIH RAZMERAH KOSOVA V žlahtnjenju rastlin igra eno od najpomembnejših vlog selekcija roditeljev z dobrimi kombinacijskimi sposobnostmi za želene lastnosti, ki jih običajno ugotavljamo z dialelnimi križanji. Namen raziskave je bil ugotoviti kombinacijsko sposobnost 10 samooplodnih linij koruze ter njihovih križancev za listno površino (LP). Na osnovi njihovih dialelnih križancev (brez recipročnih križancev) je bila za LP izračunana splošna (sKS) in posebna (PKS) kombinacijska sposobnost. Komponente genetske variabilnosti so bile računane po metodi 2 Griffingovega modela (1956) računanja kombinacijskih sposobnosti. Največja LP je bila 1 University of Prishtina, Faculty of Agriculture, Kosova 2 University of Ljubljana, Biotechnical Faculty, Slovenia, e-mail: ludvik.rozman@bf.uni-lj.si 3 University of Tirana, Faculty of Agriculture, Albania ugotovljena za križanec L6*L10, (788,6 cm2), najmanjša pa za križanec L4*L5 (558,9 cm2), medtem ko je bila povprečna vrednost vseh križancev 678,8 cm2. Tako za SKS kot za PKS so bile ugotovljene statistično značilne razlike med križanci pri p=0,01. Največja vrednost SKS za LP je bila ugotovljena pri L2 (+31,33), najnižja pa pri L4 (-38,07), medtem ko je bila največja vrednost PKS ugotovljena za križanec L6*Ll0 (+156,73). Ključne besede: koruza, samooplodne linije, splošna kombinacijska sposobnost, posebna kombinacijska sposobnost, listna površina. 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. Jevtić (1977) in his investigation found that the total surfaces of leaves/plant varied from 0.3-1.2 m2. Ničiporović (1961), and Gotlin and Pucarić, (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 Lapčević (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 Jakovljević (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, experimental plots was 5.4 m2 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, Wis 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 = j+gi+gj+s+e, Xjj - value of the progeny derived from the crossing of /-th female parent with j-th male parent j - grand mean, gi - the GCA effects of the i-th female parent, gj - the GCA effects of the j-th male parent, ss - the SCA effects specific to the hybrid of the /-th female line and the j-th 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. S.S. GCA n-1 1 Z^ + yn )2 - - y.2 ^ n SCA Error n(n -1) 2 n(n +1) 2 n + 2 ZZy2 - Z( yi+y" y +- 2 -1 n + 2 ^ (n + 1)(n + 2) , (r -1) Total S.S. - Treatm. S.S. - Replic. S.S. y.. • - S.S. out of base ANOVA. Statistical analyses package were conducted using program - MSTAT-C , version 2.10 (Russell, 1996). r 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 L6xL10, (96%) and L3xL4, (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). Kojić (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 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 L2 L3 L4 L5 L6 L7 L8 L9 L10 F1 Mean L1 489.0 625.6 681.8 715.9 752.7 721.7 580.6 617.2 662.6 643.9 666,89 L2 467.4 737.9 726.8 744.9 757.3 723.1 741.4 761.2 652,0 718,91 L3 472.8 562.8 647.6 683.6 733.8 726,0 730,6 757,8 695,77 L4 470.4 558.9 621.5 626.6 620.4 593.5 605.2 625,73 L5 440.3 626.7 685.8 703.6 583.2 597.9 655,70 L6 392.6 709.4 712.3 682.0 788.6 700,34 L7 463,0 728.0 684.9 681.2 683,71 L8 477.0 702.8 717.8 687,60 L9 490.0 628.5 669,92 L10 412.0 674,77 Grand mean 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 Kojić (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 d.f. S.S. M.S. F-Value GCA 9 125598.06 13955.34 30.71** SCA 45 1572243.67 34938.75 76.89** SE 108 49076.53 454.41 ** - 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. Kojić (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 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 LSDp=0.0i = 22.70 SE(gi) =11.3603 Table 5: Specific combining ability (SCA) for leaf area in a diallel among 10 maize inbreds. Rank Genotypes SCA Homog. groups Rank Genotypes SCA Homog. groups 1 L6> L10 156,73 a* 24 L7 L9 39,60 efghijkl 2 L1> L5 135,88 ab 25 L6 L9 39,58 efghijkl 3 L1> L4 116,51 abc 26 L1 L3 30,62 fghijklm 4 L3> L10 116,09 abc 27 L1 L9 25,57 ghijklm 5 L2> L5 95,16 bcd 28 L4 L7 18,97 hijklmn 6 L2 L4 94,49 bcd 29 L1 L10 17,50 hijklmno 7 L2 L9 91,35 bcde 30 L4 L6 16,65 hijklmno 8 L2 L6 83,08 bcdef 31 L3 L5 15,50 hijklmno 9 L1 L6 80,30 cdef 32 L4 L10 15,24 hijklmno 10 L3 L9 78,36 cdefg 33 L3 L6 14,96 hijklmno 11 L3 L7 74,36 cdefg 34 L5 L6 4,42 iiklmnop 12 L8 L10 73,65 cdefg 35 L4 L8 3,34 ijklmnop 13 L5 L8 69,07 cdefgh 36 L9 L10 1,00 ijklmnopq 14 L7 L8 66,09 cdefgh 37 L4 L9 -6,94 jklmnopq 15 L5 L7 60,55 defgh 38 L2 L10 -7,32 kKlmnopq 16 L6 L7 59,80 defghi 39 L5 L10 -9,48 lmnopq 17 L3 L8 55,19 defghi 40 L4 L5 -21,50 mnopq 18 L2 L8 54,94 defghi 41 L1 L7 -33,10 mnopq 19 L2 L3 53,84 defghi 42 L5 L9 -34,70 nopq 20 L6 L8 53,20 defghi 43 L1 L8 -36,40 opq 21 L8 L9 48,10 defghij 44 L1 L2 -43,10 pq 22 L7 L10 46,46 defghijk 45 L3 L4 -51,79 q 23 L2 L7 46,08 defghijk LSDp=0,05 LSDp=0,01 54,46 71,80 LSDp=0,05 LSDp=0,01 54,46 71,80 _SE_128,52_SE_128,52 * - 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 L3xL4 (-51.79). The total differences for maximum values for phenotype variability were 208.52 in 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 Kojić (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 REFERENCES Aliu, S. 2003. Reaction and evaluation of some maize inbred lines in agro-ecological conditions Kosova. Master Thesis, The Agriculture University of Tirana. 113 p. Aliu, S. 2006. The study of GCA and SCA for some maize inbred lines in agro-ecological conditions of Kosova. PhD Thesis, Agriculture University of Tirana. 52 p. Bocanski, J. 1996. Geneticka i fenotipska međuzavisnost morfoloških osobina i žetvenog indeksa kod BSSS formulacija kukuruza. PhD Thesis, The Agriculture Faculty of Novi Sad. 89 p. Evans, L.T. 1993. Crop evolution, adaptation and yield. Cambr. Univ. Press, Cambridge, UK. 93 p. Francis, C.A., Rutger, J.N and Palmer, A.F.E. 1969. A rapid method for plant leaf area estimation in maize. Crop Science. 9: 537-539. Gotlin, J., Pucarić, A. 2000. Proizvodnja kukuruza. Ministarstvo za poljoprivredu i šumarstvo, Zagreb. 12-13 p. Griffing, B. 1956. Concepts of general and specific combining ability in relation to diallel crossing system. Aust. J. Biol. Sci. 9: 463-493. Hayman, B.I. 1954. The theory and analysis of diallel crosses. Genetics, 39: 787-809. Jakovljević, L. 1989. Efikasnost metoda ispitivanja S1 linija i metoda test ukrstanja u cilju dobijanja genetski superiornih linija kukuruza. PhD Thesis, The Agriculture Faculty of Novi Sad. 91 p. Jevtić, 1977. Kukuruz, Nolit, Beograd. 354-372 p. Kojić, L. 1982. Nasledjivanje ugla lista i komponenti prinosa zrna kukuruza (Zea mays L.). PhD Thesis, The Agriculture Faculty of Novi Sad. 110 p. Lapčević, R. 1985. Uticaj gustine useva i vremena ubiranja na kvalitetne i bioloske osobine semena hibrida kukuruza. PhD Thesis, The Agriculture Faculty of Novi Sad. 180 p. Malik, I. 2004. General and Specific combining ability studies in maize diallel crosses. International Journal of Agriculture & Biology. 06, 5: 856-859. Mason, L., and Zuber., M.S. 1976. Diallel analysis of maize for leaf angle, leaf area, yield and yield components. Crop Science, 16: 693-696. Montgomery, J.Z., Doak, P.B. 1970. Diallel analysis of leaf area and relationships to yield in maize. Crop Science, 2:178-180. Ničiporović, A.A. 1961. Fotosinteza i teorija dobijanja visokih prinosa. Fiziologija rastenij, 8 (5): 85-100. Pearce, R.B., Mock, J.J and Bailey, T.B. 1975. Rapid method for estimating leaf area per plant in maize. Crop Science, 15: 691-694. Russel, D. 1996. MSTAT-C, version 2.10. Michigan State University. Rojas, B.A., Sprague, G.F. 1952. A comparison of variance components in corn yield trials: III. General and specific combining ability and their interactions with locations and years. Agron. J., 44: 462-466. Rutger, J.N., Francis, C.A. and Grogan, C.O. 1971. Diallel analysis of ear leaf characteristics in maize (Zea mays L.). Crop Science, 11: 194-195. Salillari, A., Fetahu, Sh., Aliu, S., Susaj, L. 2002. Biotechnology. Tirane, 45-50 p. Sylvester, A.W., Cande, W.Z., Freeling, M. 1990. Division and differentiation during normal and liguleless maize leaf development. Development Journal, 110: 985-1000. Warghese, T.M., Singh, R.K., Choudhary, B.D. 1976. Biometrical techniques in genetics and breeding. International Bioscience Publishers, Hissar, India. 248+3 p. Whigham, D.K. and Wooley, D.G. 1974. Effect of leaf orientation, leaf area and plant densities on corn production. Agron. J., 66: 482-486.