Genetic, phenotypic and ecological correlations between flowering and productivity traits in maize --Chernov, AA, Mihailov, ME It is known that in maize the genetic correlations between flowering and productivity traits are, as a rule, positive (Jugenheimer, 1976). The main reason for this effect is considered to be the capability of maize genotypes with long vegetation to use the advantage of favourable growth and maturity conditions.

In our study, the genetic correlations between ear flowering and productivity for 28 different F1 maize hybrids were also positive: 0.45* between ear flowering and total productivity, 0.46* between ear flowering and first ear productivity.

In 2002 we used two maize inbred lines (MK01 and P092) and their F1 and F2 hybrids for correlation studies. The plants were grown in the field in two blocks with a density of 5 plants/sq. meter. The flowering traits are shown in Table 1, the productivity traits in Table 2, and the ecological (for MK01, P092 and F1) and phenotypic (for F2) correlations between flowering and productivity traits in Table 3. The number of plants in blocks is different because some plants in blocks were used for self-pollination or hybridization and so were not measured.

All correlations in Table 3 are negative. The probable reason for this result is the concurrent capability for favourable growth and maturity conditions, because in our experience, the earliest plants within a definite genotype had the best productivity. This effect may by more essential in concurrent growth and maturity conditions (for example high density), and may be used for revealing the plants with high productivity within a definite genotype.

Table 1. Means of flowering traits in maize
 
   
Flowering date (days)
  
Genotype No. of plants in block
tassel
ear
 Flowering interval (days)
MK01 26
71.3+0.4
75.2+0.5
 3.9+0.2
21 71.5+0.5
75.9+0.7
4.4+0.3
  
P092 13
73.5+0.7
73.0+0.8
 -0.5+0.4
20 73.4+0.8
73.2+1.1
-0.1+0.5
  
MK01 x P092 22
69.5+0.6
70.4+0.7
 0.9+0.2
F2(MK01 x P092) 24
68.3+0.7
69.8+0.8
 1.4+0.4
  18 70.0+0.8
71.7+1.1
1.7+0.5

Table 2. Means of productivity traits in maize
 
   
First ear trait
    
Genotype No. of plants in block
kernel set (%)
grain weight (g)
cob weight (g)
 Grain weight of other ears (g) Total productivity (g)
MK01 26
99+1
102+4
17.9+0.6
 0.9+0.9 103+4
  21
97+1
98+5
18.0+0.8
 0 98+5
P092 13
87+4
33+4
6.4+0.5
 0.1+0.1 33+4
  20
76+6
26+3
7.2+0.6
 0 26+3
MK01 x P092 22
99+1
139+9
24.8+1.5
 0 139+9
F2(MK01 x P092) 24
94+3
87+7
15.5+1.1
 6.1+3.0 93+8
  18
99+0.4
98+8
16.4+1.5
 0 98+8

Table 3. Phenotypic and ecological correlations between flowering and productivity traits in maize (*P<0.05, **P<0.01, ***P<0.001)
 
Correlation traits MK01 P092 F1 F2
Kernel set- -0.53** -0.06 -0.49* -0.11
tassel flowering -0.43 -0.30 - -0.40
Kernel set- -0.46* -0.28 -0.46* -0.21
ear flowering -0.57* -0.47* - -0.48
Kernel set- -0.17 -0.50 -0.16 -0.23
flowering interval -0.55* -0.51* - -0.40
Cob weight- -0.61** -0.62* -0.72*** -0.32
tassel flowering -0.70** -0.74** - -0.36
Cob weight- -0.63** -0.71* -0.72*** -0.38
ear flowering -0.60** -0.69** - -0.42
Cob weight- -0.45* -0.27 -0.37 -0.19
flowering interval -0.16 -0.32 - -0.31
First ear grain weight- -0.79*** -0.12 -0.81*** -0.36
tassel flowering -0.84*** -0.31 - -0.46
First ear grain weight- -0.83*** -0.27 -0.74*** -0.54*
ear flowering -0.92*** -0.48* - -0.55*
First ear grain weight- -0.61** -0.33 -0.23 -0.44*
flowering interval -0.66** -0.50* - -0.45
Total productivity- -0.84*** -0.13 -0.81*** -0.36
tassel flowering -0.84*** -0.31 - -0.46
Total productivity- -0.86*** -0.27 -0.74*** -0.53*
ear flowering -0.92*** -0.48* - -0.55*
Total productivity- -0.59** -0.33 -0.23 -0.41
flowering interval -0.66** -0.50* - -0.45

 
 
 

Please Note: Notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors.

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