Correlations between biochemical quality attributes
The correlation between oil and TSS or sucrose was statistically negative at the 0.01 level, while sucrose and TSS were significantly positive at the 0.01 level, with a Pearson correlation coefficient of -0.99, -0.98 and 0.99 respectively. The correlations between the other biochemical quality attributes were not significant.
Effect Of Location, Genotype And Its Interactions On Main Quality Attributes Of Peanut
As shown in Table 1, genotype effect was significant at 0.01 or 0.05 probability level for all the biochemical attributes tested including oil, protein, TSS and sucrose contents. Location only had significant effect on TSS (at 0.05 probability level). Location × genotype interaction was significant for TSS and sucrose content at 0.05 probability level. Genotype alone contributed most of the variations in biochemical attributes with percentages of 94.49, 61.27, 89.15 and 84.69 for oil, protein, TSS and sucrose respectively.
Table 1
Analysis of variance of main biochemical quality traits of two peanut genotypes cultivated at two locations
Source of variation | Degree of freedom | Oil | Protein | TSS | Sucrose |
Mean sum of squares | F-statistic | P-value | Mean sum of squares | F-statistic | P-value | Mean sum of squares | F-statistic | P-value | Mean sum of squares | F-statistic | P-value |
Location (L) | 1 | 6.9616 | 2.037 | 0.1914 | 3.2033 | 1.053 | 0.3347 | 2.6602 | 5.515 | 0.0468 | 2.3585 | 3.318 | 0.1060 |
Genotype (G) | 1 | 482.0936 | 141.028 | 0 | 18.1056 | 5.954 | 0.0406 | 49.5727 | 102.779 | 0 | 46.3347 | 65.186 | 0 |
L × G | 1 | 17.7147 | 5.182 | 0.0524 | 5.2008 | 1.71 | 0.2273 | 2.891 | 5.994 | 0.0400 | 5.3067 | 7.466 | 0.0258 |
Error | 8 | 3.4184 | | | 3.0408 | | | 0.4823 | | | 0.7108 | | |
Total | 11 | | | | | | | | | | | | |
Table 2 listed the main effect of genotype and location on individual biochemical attributes. On average, HFLS had 12.68 percentage points more oil than LFHS, 2.46, 4.07 and 3.93 percentage points less protein, TSS and sucrose correspondingly. Peanut grown at L1 had 0.94 percentage point more TSS than that at L2.
Table 2
Main effect of genotype and location on biochemical quality
Genotype/location | Oil | Protein | TSS | Sucrose |
Genotype | | | | |
HFLS (%) | 56.21 ± 1.56A | 22.40 ± 0.57a | 6.07 ± 0.49B | 4.01 ± 0.57B |
LFHS (%) | 43.53 ± 2.83B | 24.85 ± 2.49b | 10.14 ± 1.28A | 7.94 ± 1.53A |
Difference between genotypes (%) | 12.68 | -2.46 | -4.07 | -3.93 |
Statistical significance | ** | * | ** | ** |
Location | | | | |
L1 | 49.11 ± 8.39 | 23.11 ± 0.82 | 8.58 ± 2.80 | 6.41 ± 2.92 |
L2 | 50.63 ± 5.92 | 24.14 ± 2.98 | 7.64 ± 1.84 | 5.53 ± 1.71 |
Difference between locations (%) | -1.52 | -1.03 | 0.94 | 0.89 |
Statistical significance | | | * | |
Oil, protein, TSS and sucrose contents were expressed as mean ± standard deviation (SD). |
** and * denoted significant difference at 0.01 and 0.05 probability levels, respectively. |
The results of the multiple comparisons of the biochemical quality of peanut kernels harvested from two genotypes grown at two locations in a total of four combinations were presented in Table 3. It could be noticed that at the 0.05 level, TSS and sucrose were significantly higher in LFHS than in HFLS, regardless of the location where the peanuts were grown. Compared to HFLS, LFHS had at least 3.09 and 2.60 percentage points more TSS and sucrose respectively.
Table 3
Biochemical quality of two peanut genotypes grown at two locations
Location | Genotype | Oil (%) | Protein (%) | TSS (%) | Sucrose (%) |
L1 | LFHS | 41.56 ± 0.30 | 23.68 ± 0.44 | 11.10 ± 0.05a | 9.04 ± 0.03a |
L2 | LFHS | 45.51 ± 2.86 | 26.03 ± 3.35 | 9.18 ± 1.15b | 6.83 ± 1.47b |
L2 | HFLS | 55.76 ± 0.87 | 22.25 ± 0.50 | 6.09 ± 0.24c | 4.23 ± 0.20c |
L1 | HFLS | 56.66 ± 2.16 | 22.54 ± 0.71 | 6.05 ± 0.74c | 3.78 ± 0.80c |
Figures in the same column followed by the same letter indicated that they were not significantly different at the 0.05 level. Values were expressed as mean ± standard deviation. |
Difference In Oil Body, Protein Body And Starch Grain Number And Area
Transmission electron micrographs of HFLS and LFHS cotyledon tissue were displayed in Fig. 1. The similarities and differences between the two peanut genotypes in terms of the quantity and area of oil bodies, protein bodies and starch grains were given in Table 4. In comparison with LFHS, at 0.01 level, HFLS had significantly higher number of oil bodies, total oil body area and number of protein bodies, while having significantly lower total protein body area, maximum protein body area, average area per protein body, number of starch grains, total starch grain area and average area per starch; at 0.05 level, HFLS had considerably higher average area per oil body and lower minimum protein body area and maximum starch grain area (Table 4). The maximum/ minimum oil body area and minimum starch grain area, however, did not significantly differ between the two genotypes (Table 4).
Table 4
Number and area of oil bodies, protein bodies and starch grains in cotyledonary tissue of two peanut genotypes, expressed as mean ± standard deviation
Anatomical features | HFLS | LFHS | Difference |
Value | Statistical significance |
Number of oil bodies | 1607.47 ± 57.49 | 1219.70 ± 75.85 | 387.77 | ** |
Number of protein bodies | 64.70 ± 16.78 | 46.40 ± 12.22 | 18.30 | ** |
Number of starch grains | 7.40 ± 3.16 | 12.85 ± 3.97 | -5.45 | ** |
Minimum oil body area (µm2) | 0.48 ± 0.06 | 0.38 ± 0.04 | -0.10 | |
Maximum oil body area (µm2) | 4.56 ± 0.59 | 4.50 ± 0.25 | 0.06 | |
Total oil body area (µm2) | 4450.14 ± 207.36 | 3234.19 ± 113.44 | 1215.95 | ** |
Average area per oil body (µm2) | 2.77 ± 0.10 | 2.66 ± 0.12 | 0.11 | * |
Minimum protein body area (µm2) | 3.38 ± 1.11 | 8.21 ± 5.03 | -4.82 | * |
Maximum protein body area (µm2) | 47.08 ± 1475.22 | 86.72 ± 21.39 | -39.65 | ** |
Total protein body area (µm2) | 1230.17 ± 202.60 | 2009.60 ± 293.15 | -779.43 | ** |
Average area per protein body (µm2) | 21. 16 ± 7.17 | 44.83 ± 7.46 | -23.68 | ** |
Minimum starch grain area (µm2) | 6.46 ± 4.19 | 9.66 ± 3.84 | -3.20 | |
Maximum starch grain area (µm2) | 40.39 ± 18.35 | 60.60 ± 16.49 | -20.20 | * |
Total starch grain area (µm2) | 112.30 ± 36.33 | 282.99 ± 51.26 | -170.69 | ** |
Average area per starch grain (µm2) | 16.71 ± 5.12 | 22.80 ± 3.17 | -6.09 | ** |
**Significant at 0.01 level. *Significant at 0.05 level. |
Correlations Between Oil Body, Protein Body And Starch Grain Number And Area
Table 5 presented the correlation coefficients and significance between the various ultrastructural parameters of the oil body, protein body and starch grain number and area. At the 0. 01 level, number of oil bodies was correlated positively with total oil body area (r = 0.97) and number of protein bodies (r = 0.59), and negatively with average area per protein body (r=-0.89), total protein body area (r=-0.84), total starch grain area (r=-0.83), maximum/minimum protein body area (r=-0.74, -0.65), maximum starch grain area (r=-0.57) and number of starch grains (r=-0.56); number of protein bodies was correlated positively with total oil body area (r = 0.55) and negatively with average area per protein body (r=-0.84), maximum starch grain area (r=-0.57) and minimum protein body area (r=-0.54) at the 0.01 level; number of starch grains was correlated positively with total starch grain area (r = 0.86) and negatively with total oil body area (r=-0.57). Regarding the oil body area, 0.01 level significant correlations were detected between total oil body area and average area per protein body (r=-0.86), total protein area (r=-0.85), total starch grain area (r=-0.83), maximum protein body area (r=-0.78), minimum protein body area (r=-0.60), maximum starch grain area (r=-0.55), average area per oil body (r = 0.54), and average area per starch grain (r=-0.49) (Table 5). As to protein body area, 0.01 level significant correlations were found between maximum protein body area and total protein body area (r = 0.91), between total protein body area and average area per protein body (r = 0.76), between average area per protein body and total starch grain area (r = 0.75), between maximum protein body area and average area per protein body (r = 0.71), between minimum protein body area and average area per protein body (r = 0.69), between total protein body area and total starch grain area (r = 0.68), between average area per protein body and maximum starch grain area (r = 0.64), between total protein body area and average area per starch grain (r = 0.58), between maximum protein body area or total protein body area and maximum starch grain area (r = 0.57 or r = 0.57), between maximum protein body area and total starch grain area (r = 0.55), and average area per protein body or maximum protein body area and average area per starch grain (r = 0.54 or r = 0.47) (Table 5). Minimum starch grain area was positively correlated with maximum starch grain area (r = 0.51) at 0.01 level.
Table 5
Pearson correlation coefficients between ultrastructural parameters of the oil bodies, protein bodies and starch grains
| Number of oil bodies | Number of protein bodies | Number of starch grains | Minimum oil body area | Maximum oil body area | Total oil body area | Average area per oil body | Minimum protein body area | Maximum protein body area | Total protein body area | Average area per protein body | Minimum starch grain area | Maximum starch grain area | Total starch grain area |
Number of protein bodies | 0.59** | | | | | | | | | | | | | |
Number of starch grains | -0.56** | -0.25 | | | | | | | | | | | | |
Minimum oil body area | 0.03 | -0.22 | -0.26 | | | | | | | | | | | |
Maximum oil body area | 0.03 | -0.20 | -0.25 | 0.10 | | | | | | | | | | |
Total oil body area | 0.97** | 0.55** | -0.57** | 0.12 | 0.00 | | | | | | | | | |
Average area per oil body | 0.31 | 0.13 | -0.29 | 0.35 | -0.12 | 0.54** | | | | | | | | |
Minimum protein body area | -0.65** | -0.54** | 0.20 | 0.28 | 0.08 | -0.60** | -0.06 | | | | | | | |
Maximum protein body area | -0.74** | -0.47* | 0.33 | -0.22 | 0.22 | -0.78** | -0.49* | 0.29 | | | | | | |
Total protein body area | -0.84** | -0.41* | 0.39 | -0.14 | 0.12 | -0.85** | -0.43* | 0.49* | 0.91** | | | | | |
Average area per protein body | -0.89** | -0.84** | 0.47* | 0.10 | 0.10 | -0.86** | -0.29 | 0.69** | 0.71** | 0.76** | | | | |
Minimum starch grain area | -0.48* | -0.43* | 0.15 | 0.15 | 0.11 | -0.39 | 0.13 | 0.49* | 0.31 | 0.38 | 0.45* | | | |
Maximum starch grain area | -0.57** | -0.57** | 0.21 | 0.03 | 0.28 | -0.55** | -0.19 | 0.38 | 0.57** | 0.57** | 0.64** | 0.51** | | |
Total starch grain area | -0.83** | -0.45* | 0.86** | -0.22 | -0.22 | -0.83** | -0.35 | 0.49* | 0.55** | 0.68** | 0.75** | 0.33 | 0.42* | |
Average area per starch grain | -0.51** | -0.35 | -0.13 | 0.09 | 0.03 | -0.49** | -0.14 | 0.49* | 0.47** | 0.58** | 0.54** | 0.31 | 0.38 | 0.36 |
**Significant at 0.01 level. *Significant at 0.05 level. |