Inheritance of grain yield of a half diallel in maize

Page 1

Annals of the Sri Lanka Department of Agriculture. 2008.10:67-72.

INHERITANCE OF GRAIN YIELD OF A HALF-DIALLEL IN MAIZE K.M. KARUNARATHNE1 and L.D.B. SURIYAGODA2 Field Crops Research and Development Institute, Mahailluppallama 2 Department of Crop Science, Faculty of Agriculture, University of Peradeniya 1

ABSTRACT Maize (Zea mays L.) is the most widely utilized cereal crop, which has over 500 different uses in food, feed and industry. The actual yield of the crop is very low under prevailing environmental and management conditions. Therefore, to enhance productivity, suitable varieties that can exploit limited resource conditions have to be produced. Diallel crosses are widely used among other mating designs in order to breed and evaluate the performance of newly bred varieties. Therefore, seven elite maize lines were crossed in a half-diallel scheme and the crosses were obtained and assessed at the Field Crops Research and Development Institute (FCRDI), Mahailluppallamma, during yala 2004 and maha 2004/05 seasons. Experiments were set up in a RCBD with three applications, including commercial hybrids for the purpose of comparison. The plots consisted of two 5 m long rows, spaced at 0.6 X 0.3 m. Grain yield of each plot was obtained using both rows of the plot. General and Specific Combining Ability (GCA and SCA) effects were determined. Although GCA and SCA effects were significant for both seasons, the relative contribution of SCA effects to the general variability was higher to that of GCA, since the percentage of SCA sum of squares was approximately 73% and 91% for yala 2004 and maha 2004/05 seasons respectively. The magnitude of SCA effects to the total variation indicated that dominance effects predominated for the grain yield increment, and (CML161xCML171), (CML168xCML194), (CML194xCML189), (CML171xCML193), (CML168xCML193), CML161xCML168) and (CML164xCML 168) crosses are more suitable to be used in future breeding programmes. KEYWORDS: Combining ability, CIMMYT maize line, Diallel, General combining ability, Maize, Specific combining ability.

INTRODUCTION Maize (Zea mays L.) is the most widely used cereal crop, providing raw material in food, feed and industry. The extent of land cultivated with maize in Sri Lanka, was about 25,000 ha for the last three to four decades. To cater to the increased demand created by the middle class of the country, a rapid growth in meat production, especially in poultry, was experienced in the 1990s. The ultimate result was the big demand created for maize grain in the local market, since maize being the major component in poultry feed. As the local grain production of maize fell short in both quantity and quality, the amount of imports rose within a short period, with a rise to over 200,000 t at present. While maize grain imports steadily grew, both public and private sectors launched programmes to produce quality maize grains locally as the import expenditure too accordingly increased. By


68 KARUNARATHNE AND SURIYAGODA

providing improved hybrid seed, fertilizer, loans, improved production technologies and marketing facilities etc., they helped the local farming community to enhance productivity and maize grain production in the country. As a result, the maize extents and productivity in certain districts rose several-fold, generating high incomes for maize farmers. For the increased area of maize cultivation, seed supply had to be increased, which was met solely by import of hybrid seeds. Maize hybrid seed imports are about 400t, with about 75% adoption at present. The Department of Agriculture produced a local maize hybrid in 2004, using CIMMYT (International Maize and Wheat Improvement Centre) lines and commenced its seed production for reducing dependence on imports and lowering import expenditure. Along with the normal corn hybridization programme, a Quality Protein Maize (QPM) hybrid development program was initiated, with inbred lines obtained from CIMMYT, to produce hybrids with enhanced protein quality. Hybrid development and seed production are a novel experience to Sri Lanka. Several breeding procedures have been established to increase the grain yield of the maize population and their hybrids. In order to choose the best hybrid combinations, a large number of subjectively chosen inbred lines are crossed. It would be a considerable advantage to be able to estimate the combining ability of parents and gene effects before making crosses among inbred lines. Diallel crossing programmes have been applied to achieve this goal by providing a systematic approach for the detection of suitable parents and crosses for the investigated characters, very frequently the grain yield for maize. In addition, diallel analysis provides plant breeders the opportunity to choose the most efficient selection method by allowing them to estimate genetic parameters (Verhalen and Murray, 1967). Combining ability describes the breeding values of parental lines to produce hybrids. Sprague and Tatum (1942) used the term General Combining Ability (GCA) to designate the average performance of a line in hybrid combinations, and used the term Specific Combining Ability (SCA) to define those cases in which certain combinations do relatively better or worse than would be expected on the basis of the average performance of the lines involved. In many studies, GCA effects for parents and SCA effects for crosses have been estimated in maize (Dehghanpour, Ehdaie and Moghaddam, 1996; Chaudary, Chaudary and Sharma, 1998; Araujo and Miranda, 2001). The objective of this research was to estimate the genetic parameters and to determine suitable parents and promising crosses for the


GRAIN YIELD OF A HALF-DIALLEL IN MAIZE 69

grain yield in a 7 x 7 half-diallel maize population obtained from CIMMYT under Sri Lankan conditions.


70 KARUNARATHNE AND SURIYAGODA

MATERIALS AND METHODS Seven Quality Protein Maize (QPM) inbred lines, CML161, CML164, CML168, CML171, CML189, CML193 and CML194 (CMLCIMMYT maize line), were selected from the gene bank of International Maize and Wheat Improvement Centre (CIMMYT) in Mexico and were planted at the Field Crops Research and Development Institute, Mahailluppallama, for seed multiplication purposes. Half-diallel crosses developed among 7 QPM lines (twenty one crosses and seven self lines) were thereafter tested using three replicates for the evaluation of promising hybrids in terms of grain yield during yala-2004 and maha-2004/2005 seasons. During yala-2004 only the crosses were used for yield evaluation due to inadequate seed availability of one inbred. Apart from the inbred lines and crosses, widely cultivated and experimented local hybrid, Sampath and the commercial hybrid Pacific 984 were included in the maha-2004/2005 experiment for comparison purposes. The plots consisted of 2 rows; 5.0 m long and spaced 0.6 m and plants were spaced 0.3 m apart within a row. Diazinon 3% granules (12 to 15 kg per ha) were added to the whorl of 3 week old plants to control stalk borer damage. Fertilizer was added at the recommended rates by the Department of Agriculture for yala and maha crops respectively. Grain yields of each genotype were obtained from the plots and yield was expressed in t/ha. Hayman (1954), Griffing (1956), and Cockerham (1963) model I method was used to test the significance of combining abilities. Thereafter, General Combining Ability (GCA) for each line and Specific Combining Ability (SCA) for each cross was obtained as described by Hallauer and Miranda (1988). Genetic parameters were estimated using the SAS (2002) diallel analysis programme developed by Suriyagoda and Peiris (2008). Analysis was performed separately for the two seasons. RESULTS AND DISCUSSION Preliminary analysis of variance, including GCA and SCA effects indicated that genotypes were significantly different in terms of grain yield. Observations were same for both seasons (Table 1). Average grain yield of pure lines, average grain yield of offdiagonal crosses and the GCA values for each parent are shown separately for both seasons in Table 2. CML189 had the highest GCA values for both seasons and CML193 and CML168 showed lowest GCA values representing 6th and 7th ranks respectively. Thus, GCA effect of parental lines for two seasons was fairly consistent.


GRAIN YIELD OF A HALF-DIALLEL IN MAIZE 71 Table 1. Preliminary ANOVA for the RCBD, providing the significance of GCA and SCA effects. Source Replicate Crosses GCA SCA Residual Total

yala 2004 df SS 2 11.55 20 65.96 6 17.71 14 48.25 40 39.34 62 116.85

P 0.01 0.00 0.02 0.00

maha 2004/2005 df SS 2 0.04 27 199.90 6 17.91 21 181.99 54 32.66 83 232.60

P 0.97 0.00 0.00 0.00

The average yield of off-diagonal cross CML189 was the highest and yield of CML168 was the lowest during yala-2004 season among the CML lines and the difference was significant (p ≤ 0.05) (Table 2). However, local hybrid Sampath had a similar yield as the best CML189 line. Contrastingly, the grain yield of Sampath was similar to that of the CML lines tested during maha-2004/2005 season while the standard hybrid Pacific-984 showed significantly higher yields. Also, yield of CML189, CML161, CML194 and CML164 were similar to that of Sampath during yala-2004 (Table 2). Table 2. Average grain yield and other parameters of pure lines, for the two seasons. Parent

CML161 CML164 CML168 CML171 CML189 CML193 CML194 Sampath Pacific 984

yala 2004 Yield of pure lines 3.38 2.09 na na 2.94 1.86 2.59 6.22 na

Yield of offdiagonals 5.28 ab 4.88 ab 4.41 a 4.65 a 5.43 b 4.62 a 5.04 ab 6.22 b na

GCA 0.451(2) -0.025 (4) -0.587 (7) -0.301 (5) 0.634 (1) -0.336 (6) 0.163 (3)

maha 2004/2005 Yield of Yield of pure offlines diagonals 2.47 4.42 a 2.86 4.62 a 1.49 4.18 a 3.53 4.62 a 2.39 5.18 a 1.76 4.39 a 3.09 5.07 a 5.52 5.52 ab 5.89 5.89 b

GCA -0.179 (5) 0.021 (4) -0.470 (7) 0.094 (3) 0.408 (1) -0.273 (6) 0.400 (2)

na-Not available Yield is given in t/ha. Different letters followed by yield values indicates the significant difference at (p ≤ 0.05).

SCA effects and average grain yield for the crosses are given in Table 3 and Table 4 separately for the two seasons. The crosses that showed highest SCA values were CML171xCML161 for yala-2004 and CML189x CML194 for maha-2004/2005 season. Further, CML168xCML194, CML171 xCML193, CML161xCML168, CML168xCML193 and CML164xCML168 showed higher positive SCA values for both seasons. Contrastingly, SCA values of crosses CML161xCML164, CML168xCML171 and CML193x CML194 were the lowest for both seasons. In addition, the SCA values of allself progeny were negative during the maha-2004/2005 season (Table 3 and Table 4).


72 KARUNARATHNE AND SURIYAGODA Table 3. SCA effects and average grain yield of the crosses in yala-2004. Parents CML161 CML164 CML168 CML171 CML189 CML193 CML194

SCA values and the grain yield of crosses CML161 CML164 CML168 CML171 -0.84 0.45 1.03 4.48 0.98 0.77 5.21 5.27 -3.01 6.08 5.34 1.00 5.93 4.76 5.36 5.33 4.77 4.25 4.36 5.16 5.19 5.16 5.26 4.98

CML189 -0.05 -0.75 0.41 0.10 5.37 5.82

CML193 -0.25 -0.29 0.39 0.90 0.17

CML194 -0.33 0.12 0.78 0.22 0.12 -0.92

3.81

Above diagonal and below diagonal values indicate the SCA effects for yala-2004 and respective average grain yield (t/ha) respectively. Table 4. SCA effects and average grain yield of the crosses in maha-2004/2005. Parents CML161 CML164 CML168 CML171 CML189 CML193 CML194

SCA values and the grain yield of crosses CML CML CML CML 161 164 168 171 -1.55 -0.19 1.60 0.36 4.02 -1.56 1.09 0.70 5.33 5.02 -1.95 -2.82 4.65 5.19 1.18 -1.03 4.90 4.10 4.93 6.17 4.41 5.21 5.06 5.85 5.13 5.13 6.27 5.74

CML 189 0.30 0.09 0.61 1.30 -2.80 5.67 7.31

CML 193 0.49 1.09 1.43 1.66 1.16 -2.07 2.81

CML 194 0.53 0.34 1.97 0.87 2.13 -1.69 -2.08

Above diagonal and below diagonal values indicate the SCA effects for maha-2004/2005 and respective average grain yield (t/ha) respectively. Underlined diagonal values indicate the SCA values for the pure lines.

Parents in the diallel cross were selected from CIMMYT since they were tested in environments similar to that of Sri Lankan conditions. GCA and SCA effects were highly significant (p ≤ 0.05) for both seasons indicating their significant variability of genetic potential on grain yield (Table 1). Even though the yield responses of CML lines during yala were significantly different, during maha such a yield difference among CML lines was not observed. This might be due to the significant interaction at the preliminary analysis as the season and cross effect. Further, better performing lines in terms of grain yield had higher positive GCA values and CML parents with lower grain yield showed negative GCA effects. The quantitative estimates of the GCA effects of parents were also lower than the SCA estimates for most of the lines. Further, the low GCA estimates of most parents may also indicate that transfer of quantitative traits requires more expense in breeding, e.g. by selecting cycles in segregating generations or by multiple crosses to accumulate yield related traits. In both seasons the major part of genetic variability was due to the SCA. The percentage of SCA sum of squares is approximately 73% and 91% for yala-2004 and maha-2004/2005 seasons respectively. This suggests that there is sufficient dominance gene action to support a breeding programme for maize grain yield.


GRAIN YIELD OF A HALF-DIALLEL IN MAIZE 73

Grain yield from the crosses as well as the SCA values revealed that the genotypic background contributes considerably to the grain yield. In this experiment, higher positive SCA effects occurred more frequently in the higher yielding lines, and negative SCA effects in populations with lower yield potential. Several crosses had means that surpassed the highest yielding parent, resulting in improved yield response. This knowledge of quantitative yield advantage of parents may be of significant benefit in planning genetic combinations. CONCLUSIONS Since individual plant data were not available for each line, information on heritability was not obtained. Considering SCA estimates of both seasons, (CML161xCML171), (CML168xCML194), (CML194x CML189), (CML171xCML193), (CML168xCML193), CML161xCML168) and (CML164xCML168) crosses could be considered suitable to be used in future breeding programmes for higher grain yield. Further, the resistances of these lines to pest and disease conditions and to diverse environments at different locations needs further investigations. REFERENCES Araujo, P.M. and J.M. Miranda. 2001. Analysis of diallel crosses for evaluation of maize populations across environments. Crop Breeding and Applied Biotechnology 1:255-262. Chaudhary, A.K., L.B. Chaudhary and K.C. Sharma. 1998. Combining ability estimates of early generation inbred lines derived from two maize populations. Indian Journal of Genetics and Plant Breeding 60:55-61. Cockerham, C.C. 1963. Estimation of genetic variances. In Statistical Genetics and Plant Breeding, Eds. W.D.Hanson and H. F. Roberson Pp: 53-93. National Academy of Science, National Research Council, Washington, DC. Dehghanpour Z., B. Ehdaie and M. Moghaddam. 1996. Diallel analysis of agronomic characters in white endosperm maize. Journal of Genetics and Plant Breeding 50:357-365. Griffing, B. 1956. Concept of general and specific combining ability in relation to diallel crossing systems. Australian Journal of Biological Sciences 9:463-493. Hallauer A.R. and J.B. Miranda. 1988. Quantitative genetics in maize breeding. Second edition. Iowa state University press. Ames. 267-294 p. Hayman, B.I. 1954. The theory and analysis of the diallel crosses. Genetics 39:798-809. SAS Institute. 2002. SAS/STAT-9 User’s Guide. Pp 22. SAS Institute, Cary, NC. Sprague, G.F. and L.A. Tatum. 1942. General vs. specific combining ability in single crosses of corn. Journal of the American Society of Agronomy 34:923-932. Suriyagoda, L.D.B. and B.L. Peiris. 2008. Estimating genetic parameters from diallel experiments using SAS/IML. Sri Lankan Journal of Applied Statistics 08:83-94. Verhalen, L.M. and J.C. Murray. 1967. A diallel analysis of several fiber property traits in upland cotton. Crop Science 7:501-505.


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