African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6638

Full Length Research Paper

Correlation analysis for grain yield and other agronomic parameters for 90 single crosses hybrid maize evaluated in three agrological zones in Ghana

Ndebeh J.
  • Ndebeh J.
  • Central Agricultural Research Institute (CARI), Suakoko District, Bong County, Liberia.
  • Google Scholar
Akromah R.
  • Akromah R.
  • Department of Crop and Soil Sciences, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
  • Google Scholar
Vah E. G.
  • Vah E. G.
  • Agronomist, Project Management Unit (PMU) Ministry of Agriculture, Republic of Liberia, Liberia.
  • Google Scholar
Kolleh D. S.
  • Kolleh D. S.
  • Central Agricultural Research Institute (CARI), Suakoko District, Bong County, Liberia.
  • Google Scholar
Baysah N. S.
  • Baysah N. S.
  • Central Agricultural Research Institute (CARI), Suakoko District, Bong County, Liberia.
  • Google Scholar


  •  Received: 03 August 2017
  •  Accepted: 26 October 2017
  •  Published: 21 December 2017

 ABSTRACT

A trial was conducted to determine the correlation between grain yield and agronomic parameters of 90 F1 early maturing maize hybrids in 2012 in Fumesua, Ejura and Kpeve; representing the Forest, Forest-Savannah Transition and Coastal- Savannah Transition zones of Ghana, respectively.  The objective of the work was to determine the correlation between grain yield and other agronomic parameters of maize across three locations. Randomized Complete Block Design (RCBD) with two replicates was used for each location. Results from the correlation analysis revealed that grain yield was significantly and positively correlated with plant height (r = 0.633), cob length (r =0.610) ear height (r =0.410), and cob diameter (r = 0.401). However, there were nonsignificant correlation between grain yield and days to silking. Nevertheless, among agronomic traits, ear height, plant height seed length, seed diameter, cob length and cob diameter were positively and significantly correlated, indicating that increase in any one of these traits could lead to increase in the other. It was recommended that hybrids that showed the highest correlation with grain can be selected to improve grain yield.

Key words: Maize, correlation, genotype, hybrid, adaptability, yield, agroecology.


 INTRODUCTION

Maize (Zea mays L.) is the most widely grown cereal in the world, and it is the third most important cereal crop after wheat and rice which serves as a primary staple food in most developing countries (Khalil et al., 2011; Badu-Apraku et al., 2010; Obeng-Bio, 2010). The maize plant has wider adaptability hence can be cultivated in different growing conditions from latitude 58°N to 40°S, below sea level and at altitude higher than 3000 m, and in areas with rain-fall of about 250 to 5000 mm per annum and with growing season ranging from three months to about 13 months (Golam et al., 2011). Its high yield potential, wide adaptability, relative ease of cultivation, processing, storage and transportation has increased its potential for combating food security challenges posed by population increase and changes in climatic conditions due to global warming in West and Central Africa (Badu-Apraku et al., 2010).
 
Maize is grown in approximately 25 million hectares in Sub-Saharan Africa, largely by subsistence farmers that produced 38 million tons in 2005 to 2008, primarily for food (Smale et al., 2011). From 2005 to 2008, maize represented an average of 27% of cereal area, 34% of cereal production and 8% of the value of all primary crop production (FAO STAT, 2014; Smale et al., 2011). In Ghana, maize is the highest ranking cereal in terms of production and consumption followed by rice (Twumasi-Afriyie et al., 1992). The domestic demand is growing because it serves as a major source of daily calories and dietary protein for most people who are under privileged, since poverty makes it difficult for such people to afford meat (MiDA, 2006). According to a MOFA (2006) annual report, maize accounted for 50 to 60% of total production area of cereals with average yield approximately at 1.6 metric tons per hectare, but yields as high as 4.5 to 5.0 metric tons per hectare can be realized by farmers using improved seeds and good management practices.


 MATERIALS AND METHODS

Research location
 
The experiment was conducted in three agro-ecological zones of Ghana. The locations where the experiment was conducted were different in mean seasonal rainfall (Table 1). Fumesua lies in the Forest ecology zone of Ghana. Ejura lies in the Forest –Savannah Transition ecology and Kpeve lies in the Coastal-Savanna Transition. The three experimental sites experience a bimodal rainfall pattern. The major season stretches from April through July, and the minor season from August to November (Table 2).
 
 
 
Research materials
 
Experimental design
 
The ninety F1s were constituted into a hybrid trial and planted in a random complete block design at each of the sites. Prior to planting, the site was thoroughly prepared with plough and harrow using tractor. Each entry was planted in a one row of 5 m, spacing between hills of 0.45 m and spacing between rows of 0.75 m with two replications at each of the three evaluation sites. Each plot in the trial contained 11 hills, and each row contained 22 plants to obtain a target plant density of approximately 60,000 plants ha-1.
Crop husbandry
 
Pre-emergence and post emergence chemical weed control was done with an application of Gramoxone and Atrazine respectively. Hand weeding was also done when necessary to control weeds during the growing period. NPK 15-15-15 fertilizer was applied at the rate of 30 kg N ha-1and 60 kg P2O5 ha-1 as basal fertilizer at two weeks after planting and top-dressed with additional N at 60 kg N ha-1 at 4 weeks after planting. The trials were conducted under rain-fed condition, and other management practices were done according to the recommendations of the specific areas.
 
Data collection
 
Data were collected on the following parameters prior to harvesting:
 
Days to 50% tasseling
 
This was calculated as the number of days from the date of sowing to the day at which 50% of plants in a plot showed full tassel emergence.
 
Days to 50% silking
 
The number of days from the date of sowing to the day on which 50% of the plants in a plot showed complete silk emergence.
 
Plant height
 
The height of five randomly selected plants in a plot were measured in centimeter with a graduated measuring stick from the ground level to the node bearing the flag leaf and averaged.
 
Ear height
 
The ear heights of the five previously selected plants in each plot were measured in centimeters from ground level to the node bearing the uppermost ear and averaged.
 
Cob length
 
The length of the cob was measured in centimeters using Vernier caliper (from the base of the ear to the tip). Five cobs were chosen at random from each plot and averaged.
 
Cob width
 
The widths of five randomly selected cobs were measured in centimeters as the thickness of the ear using Vernier caliper. Ten cobs were chosen at random from each plot and averaged.
 
Grain yield
 
Grain yield kg ha-1 was calculated for every entry from the data of harvested ear weight per plot using the following formula:
 
Grain yield (kg ha-1) was calculated as = Harvested ear weight (kg plot-1) × (100-MC) × 0.8 × 10,000/ (100-15) × 3.75 m2 (at 15% moisture).
 
Seed length
 
The length of ten randomly selected seeds were measured in centimeters using Vernier caliper and averaged.
 
Seed diameter
 
The widths of ten randomly selected seeds were measured in centimeters as the thickness of the seed using Vernier caliper and averaged.
 
Data analysis
 
The Analysis of Variance (ANOVA) according to Steel and Torrie (1980) for grain yield and agronomic parameters was conducted using Statistical Analysis System version 9.2 (SAS, 2003). Least significance difference test (p≤0.05) was used to determine the level of significance among measured parameters. Pearson coefficients of correlation were calculated using the hybrids’ least square means for all parameters to determine associations among these parameters. Correlation coefficients ranged in values between -1 and +1; a perfect negative relationship and a perfect positive relationship respectively.


 RESULTS AND DISCUSSION

Mean performance of the genetic materials evaluated
 
Mean performance of the crosses are presented in Table 4. Mean grain yield was 4598 kg ha-1 with yield ranging from 1058.4 kg ha-1 (TZEI-45 × TZEI-47) to 6296 kg ha-1 (TZEI-36 × TZEI-39). The mean performance for plant height showed that differences among genotypes were highly significant (p<0.01) (Table 3). Mean plant height across environments (Table 4) was 160.9 cm, and ranged from 115 to 186.4 cm. TZEI-12 × TZEI-13 recorded the lowest height (115 cm) while TZEI-39 × TZEI-22 recorded the highest height (186.4 cm). The result showed that there were highly significant differences among genotypes (P<0.01) for ear height (Table 3). Mean ear height (Table 4) was 76.9 cm ear height ranged from 52.1 cm (TZEI-12 × TZEI-13) to 97.2 cm (TZEI-35 × TZEI-19).
 
 
 
Meanwhile, TZEI35 × TZEI19 recorded the highest ear height while TZEI12 × TZEI 13 recorded the lowest ear height. The result for days to silking showed that there were highly significant differences among genotypes (P<0.01). Days to silking ranged from 38 to 54 days. The mean days to silking (Table 4) was at 50 days. TZEI-45 × TZEI-47 was the latest to reach mid-silk, while TZEI-9 × TZEI-12 was the earliest to reach mid- silk. From the result (Table 3), differences in days to tasseling among genotypes were highly significant (p<0.01). Mean days to tasseling (Table 4) was 47.6 days. Days to mid-tasseling ranged from 43 to 51.2 days. TZEI-12 × TZEI-13 recorded the highest number of days to tasseling while TZEI-9 × TZEI-12 recorded the lowest days to tasseling. The mean square (Table 3) for seed diameter showed highly significant differences among genotypes (p<0.01).
 
Seed diameter ranged from 0.7cm (TZEI-14 × TZEI-17) to 0.9 cm (TZEI-3 × TZEI-1). The result from the analysis for seed length (Table 3) indicated that differences among the genotypes were significant (P<0.05). Seed length ranged from 0.8 cm (TZEI-28 × TZEI-14) to 1.5 cm (TZEI-41 × TZEI-30) (Table 4). The data analysis for cob length (Table 3) revealed that differences among genotypes were highly significant (P<0.01). Mean cob length was 13. 4 cm and cob length ranged from 9.4 cm (TZEI-28 × TZEI-14) to 15.2 cm (TZEI-24 × TZEI-23) (Table 4). The mean square analysis for cob diameter (Table 3) revealed that differences among genotypes were highly significant (P<0.01). Mean cob diameter (Table 4) was 4.2 cm. TZEI-42 × TZEI- 22 recorded the highest value (5.6 cm) while TZEI-28 × TZEI-14 recorded the lowest value (2.9 cm) for cob diameter.
 
Correlations among agronomic parameters measured
 
Identification of superior hybrids
 
The primary trait, grain yield, is a quantitatively inherited trait with low heritability. Several studies have indicated that highly significant phenotypic correlations between yield and many secondary traits can be found (Nzuve et al., 2014). The use of secondary traits in breeding can increase breeding progress as compared to selection for yield alone (Edmeades et al., 1997). A superior maize hybrid must be high yielding and also must possess desirable agronomic characters. The correlation studies revealed that plant height was strongly associated with grain yield, ear height, days to tasseling, cob length and diameter, seed length and seed diameter. This indicates that any one of these traits could be used to select for the other. The significant differences recorded for the different traits among the genotypes studied (Table 3) implied that the maize genotypes included in this study had diverse genetic backgrounds (Vashistha et al., 2013; Reddy et al., 2012).
 
Thus, the genetic variability recorded in this study could be exploited by plant breeders to develop hybrids adapted to the diverse environments in sub Saharan Africa to improve food security status (Feuillet et al., 2012). The significant genotype by environment interaction showed a wide variability with regard to the tested genotypes and the environments involved in this study (Alake et al., 2008). Results on correlation among parameters are presented in Table 5. The correlation studies among traits showed that grain yield was positively correlated to days to tasseling, ear height, plant height, cob length, cob diameter, seed length and seed diameter with the highest effect on plant height (r = 0.633) and cob length (r = 0.610) and ear height (r = 0.410). 
 
 
The associations were highly significant (p < 0.001). This indicates that improvement on any of these characters could help improve grain yield. Similar results were reported by Bocanski et al. (2009) and Malik et al. (2005). They observed high and positive correlation between grain yield and plant height (r = 0.953), ear height (r = 0.867), and cob length (r = 0.959). Meanwhile, days to silking has no significant correlation with grain yield, plant height, seed length, seed diameter, cob length and cob diameter. This result is in agreement with Golam et al. (2011), who reported that grain yield and plant height did not correlate with days to silking. However, among agronomic traits, ear height, plant height, seed length, seed diameter, cob length and cob diameter were positively and significantly correlated, indicating that increase in any one of these traits could lead to increase in the other.
 
Ear height significantly correlated with plant height seed length, seed diameter, cob length, and cob diameter. The strong correlation between ear height and plant height with grain yield suggested that tall plants with high ear placement gave better yields compared to the shorter plants with lower ear placement. This could be attributed to the high dry matter accumulation function carried out by the high number of leaves possessed in the case of tall plants (Al-Tabbal et al., 2012). There were negative correlations between ear height and days to silking and days to tasseling (r = - 0.369 and r = - 0.332). This result is in agreement with that of Malik et al. (2005). The negative correlation indicates that increase in days to silking and tasseling could indirectly reduce yield through stalk and root lodging (Malik et al., 2005).
 
Plant height had low correlation with days to silking, but highly correlated with ear height (r = 0.668), days to tasseling (r = 0.10692), seed diameter (r = 0.2204), cob length (r = 0.4568), cob diameter (r = 0.3989) and seed length (r = 0.3396).  This result indicates that increase in plant height could lead to increase in these characters which could result in yield increase, since plant height has been observed to be controlled by the expression of many genes and the interactions between these genes (Bello et al., 2012). Therefore, traits that positively contribute the highest correlation with grain yield such as plant height, cob length, and ear height and cob diameter can be chosen as superior characteristics to help improve maize grain yield (Table 5).


 CONCLUSION

The correlation studies among traits showed that grain yield was highly correlated with plant height, ear height, days to tasseling, cob length, cob diameter, seed length, and seed diameter with plant height contributing the highest effect (r = 0.633) followed by cob length (r = 0.610) and cob diameter (r = 0.402).This genetic diversity and the strong genetic association between grain yield and the agronomic traits would help in indirect selection thereby aiding breeders in the development of better hybrids for resource poor farmers. 


 CONFLICT OF INTERESTS

The authors have not declared any conflict of interests.



 REFERENCES

Alake CO, Ojo DK, Oduwaye OA, Adekoya MA (2008). Genetic variability and correlation studies inyield and yield related characters of tropical maize (Zea mays L.). Asset Series A. 8(1):14-27.

 

Al-Tabbal JA, Al-Fraihat AH (2012). Genetic variation, heritability, phenotypic and genotypic correlation studies for yield and yield components in promising barley genotypes. J. Agric. Sci. 4(3):193.

 
 

Badu-Apraku B, Menkir A, Ajala SO, Akinwale RO, Oyekunle M, Obeng-Antwi K (2010). Performance of tropical early maturing maize cultivars in multiple stress environments. Can. J. Plant Sci. 90:831-852.
Crossref

 
 

Bello OB, Abdulmaliq SY, Ige SA, Mahamood J, Oluleye F, Azeez MA, Afolabi MS (2012). Evaluation of early and late/intermediate maize varieties for grain yield potential and adaptation to a southern Guinea savanna agro-ecology of Nigeria. Sch. J. Agric. Sci. 2(3):42-51.

 
 

Bocanski J, Sreckov Z, Nastic A (2009). Genetic and phenotypic relationship between grain yield and components of grain yield of maize (Zea mays L.). Genetika 41(2):145-154.
Crossref

 
 

Edmeades GO, Bola-os J, Chapman SC (1997). Value of secondary traits in selecting for drought tolerance in tropical maize. In G.O. Edmeades, M. Banziger, HR. Mickelson, and C.B. Pena-Valdivia (eds.), Developing Drought and Low N Tolerant Maize. Proceedings of a Symposium, Elbatán, Mexico. pp. 222-234.

 
 

Food and Agriculture Organization Corporate Statistical Database (FAOSTAT) (2014). Statistical database of the Food and Agriculture of the United Nations. FAO, Rome.

 
 

Feuillet C, Stein N, Rossini L, Praud S, Mayer K, Schulman A, Appels R (2012). Integrating cereal genomics to support innovation in the Triticeae. Funct. Integr. Genom. 12:573-583.
Crossref

 
 

Golam F, Farhana NN, Zain MF, Majid NZ, Rahman MM, Rahman MM, Kadir MA (2011). Grain yield and associated traits of maize (Zea mays L.) genotypes in Malaysian tropical environment. Afr. J. Agric. Res. 6(28):6147-6154.

 
 

Khalil AI, Ur- Rahman H, Ur-Rehman N, Arif M, Khalil IH, Iqbal M, Hidayatullah, Afridi K, Sajjad M, Ishaq M (2011). Evaluation of maize hybrids for grain yield stability in North-West of Pakistan. Sarhad J. Agric. 27(2):213.

 
 

Malik H, Malik SI, Hussain M, Ur-Rehman S, Habib C, Javid I (2005). Genetic correlation among various Quantitive characters in maize (Zea mays L.) hybrids. J. Agric. Social Sci. 1813–2235/2005/01–3–262–265.

 
 

Millennium Development Authority (MiDA) (2006). Maize, Soya and Rice production and Processing, 4th Floor, Heritage Tower, 6th Avenue, Ridge West, PMB 56, Stadium Post Office Accra, Ghana.

 
 

Ministries of Food and Agriculture (MoFA) (2006). Maize value chain study in Ghana, enhancing efficiency and competitiveness. Statistics Research and Information Directorate of Ghana 

View

 
 

Nzuve F, Githiri S, Mukunya DM, Gethi J (2014). Genetic variability and correlation studies of grain yield and related agronomic traits in maize. J. Agric. Sci. 6:9.
Crossref

 
 

Obeng-Bio E (2010). Selection and ranking of local and exotic maize (Zea mays L.) genotypes to drought stress in Ghana. MSc Thesis, department of Crop and Soil Sciences, Faculty of Agriculture Kwame Nkrumah University Science and Technology.

 
 

Reddy VR, Jabeen F, Sudarshan MR, Rao AS (2012). Studies on genetic variability, heritability, correlation and path analysis in maize (Zea mays L.) Over locations. Int. J. Appl. Biol. Pharmaceut. Technol. 4(1):196-199.

 
 

SAS Institute Inc. (2003). SAS proprietary software, SAS Institute, Inc, Cary, NC, Canada.

 
 

Smale M, Byerlee D, Jayne TS (2011). Maize Revolution in Sub-Saharan Africa Tegemeo Institute of Agricultural Policy and Development P.O Box 20498, 00200, Nairobi, Kenya.

 
 

Steel RGD, Torrie JH (1980). Principles and procedures of Statistics: A biometrical approach, 2nd Ed. McGraw-Hill Book Company pp. 195-220.

 
 

Twumasi-Afriyie S, Badu-Apraku B, Sallah PYK, Dzah BD (1992). Thepotentials of Maize as a source of quality protein for Ghana. A paper presented at the 12th National maize and legumes workshop organized by Ghana Grains Development Project, Crops Research Institute P 9.

 
 

Vashistha A, Dixit NN, Dipika SSK, Marker S (2013). Studies on heritability and geneticadvance estimates in Maize genotypes. Biosci. Discov. 4(2):165-168.

 

 




          */?>