**3. Results**

Environmental effect was significant (p < 0.01) for all agronomic and aflatoxin accumulation resistance traits except open-tip while genotypic mean squares were significant for all measured traits (**Tables 2** and **3**). Genotype by environment interactions were significant (p < 0.05) for all traits except days to 50% pollen and silking and streak incidence.

Broadsense heritability showed relatively low to high estimates for agronomic traits, ranging from 18.90% for open-tip to 62.70% for grain yield. For the disease traits, estimated broad sense heritability ranged from a relatively low values of 9.70% for rust incidence to 24.40% for maize streak virus disease incidence. Other traits with relatively moderate to high heritability estimates were ear (67.30%) and plant heights (78.00%).

#### **3.1 Aflatoxin accumulation resistance and agronomic performance of germplasm**

Generally, performance of the thirty-six genotypes showed significant (p < 0.05) differences in aflatoxin accumulation (**Table 4**). Aflatoxin accumulation ranged from a minimum of 14.85 ppb for MP705 to a maximum of 140.60 ppb for HONAMPA (local check). Grain yield varied from 565.63 kg ha−1 for MP715 (inbred) to 4721.03 kg ha−1 for AHODZEN (OPV) with a mean of 1853.22 kg ha−1 (**Table 5**). Days to 50% pollen ranged from 48 days to 62 days whilst days to 50% silking ranged between 50 and 65 days. Anthesis silking interval varied from 2 to 4 days with an average of 3 days.

The number of ears per plant ranged from approximately 1 to 2 whilst means for cob aspect, plant aspect and open-tip were 2.01, 1.97 and 1.49, respectively. Generally, an observed mean of 1.24 for insect damage (**Table 6**) was an indication of partial tolerance of the germplasm utilized, nonetheless, OMANKWA and NC340 appeared moderately susceptible to insect damage.

Analysis of stay-green characteristics revealed NC298 as the genotype with prolonged green pigmentation whilst CML11 had less and reduced pigmentation (**Table 6**). Means observed for rust, blight and streak resistance indicated a fairly tolerant germplasm. Mean scores obtained for ear rot showed appreciable tolerance of the germplasm whilst plant height ranged between 100.73 cm and 176.25 cm. Ear height also varied from 52.24 cm to 92.50 cm.

#### **3.2 Location effect on aflatoxin accumulation resistance**

A combined analysis of aflatoxin accumulation resistance among genotypes evaluated across the three locations in two seasons was significant (p < 0.05) and variable (**Table 7**). The general observation showed a relatively high aflatoxin accumulation among genotypes evaluated in Wenchi (transitional savanna zone) whilst those evaluated across Akomadan (forest transitional zone) and Fumesua (rain forest zone) recorded relatively low amount of the toxin. Aflatoxin levels



**Table 2.**

*Genetic Variation and Aflatoxin Accumulation Resistance among 36 Maize Genotypes Evaluated… DOI: http://dx.doi.org/10.5772/intechopen.96461*



**Table 3.**


#### **Table 4.**

*Mean aflatoxin accumulation levels among 36 genotypes across six environments.*



> **Table 5.**

*Grain yield and agronomic performance of 36 genotypes across six environments.*



> **Table 6.**

*Means of 36 genotypes for disease and agronomic traits across six environments.*

*Cereal Grains - Volume 2*


**Table 7.**

*Top 15 aflatoxin resistant and worst genotypes across six environments in three locations.*

*Genetic Variation and Aflatoxin Accumulation Resistance among 36 Maize Genotypes Evaluated… DOI: http://dx.doi.org/10.5772/intechopen.96461*

vin Wenchi ranged between 21.80 ppb for MP715 to 190 ppb for HONAMPA. In Fumesua, the accumulation level ranged between 14.70 ppb for MP715 to 179.7 ppb for HONAMPA whilst in Akomadan, it ranged between 14.51 ppb to 193.13 ppb for same genotypes.

MP715 appeared to be the most stable and resistant line across the six environments within the three locations whilst HONAMPA consistently performed poorly as the worse or most susceptible genotype (**Table 7**). The ranking order of resistance in terms of aflatoxin accumulation varied among genotypes from one location to the other. However, some particular genotypes consistently appeared in the top ten resistant genotypes irrespective of location.
