Progress in development of maize inbred lines in Turda, Romania --Has, V, Cabulea, I, Has, I, The maize breeding program at the Agricultural Research Station from Turda, Romania has been developed and finished during the years 1983-2001: 250 normal endosperm inbred lines, 11 opaque2 endosperm inbred lines, and 20 sugary1 endosperm inbred lines.

In developing the inbred lines, the following sources have been used: local open-pollinated populations and varieties, synthetic populations (unimproved sources), synthetic based on inbred lines, single and more complex hybrids, initial materials resulting from an improvement program (backcross progenies) of elite inbred lines, and a quality breeding program (Table 1). Some elite inbred lines were improved in a special program (recurrent selection) for resistance to stalk and ear rot, to European corn borer, for cold tolerance or were converted to various male-sterile cytoplasms and/or to restorer of fertility (Table 2).

The methods used for development of the inbred lines were recurrent selection, pedigree method with early and late testing for general and specific combining ability (Table 3). The three inbred lines used as testers were selected from different heterotic groups. Phenotypic selection at high density (90,000 plants/ha) was at least as effective as testcross selection in screening the elite inbred lines.

Use of the improving sources led to finalization of a high ratio of the elite inbred lines. The local populations would be used as initial material only after they were improved in a special program by recurrent or reciprocal-recurrent selection.

The new elite inbred lines are parental forms of the most registered hybrids and new hybrids in official trials, which means real genetic progress in development of inbred lines at the Agricultural Research Station, Turda, Romania, during the years 1983-2001.

Table 1. Proportion of the finalized inbred lines related to the origin of initial materials.
 
Origin of initial material No.inbred lines Ratio (%)
Open-pollinated populations, local varieties, synthetics 7 3
Composites 35 14
Backcross progenies 117 47
Hybrids 91 36
Total 250 100

Table 2. "Per se" value of some inbred lines developed at A.R.S.Turda, Romania, during 1983-2001.
 
             
Inbred lines reactions to:
Inbred line
Kernel type
No.days (sowing-silking) (W153R=79days)
Stalk lodging (%)
Ear rot (note; 9=very good)
Ear length (cm)
No. kernel rows/ ear
cms C
cms T
Inbred lines developed from: open-pollinated populations, local varieties, synthetics
TA 23
flint
72
10
3
12.0
12-14
Nrf
Nrf
TA 24
flint
72
10
3
12.5
12
pRf
Nrf
TB 330
flint
83
1
5
14.5
16
-
Nrf
Inbred lines developed from composites
TD 230
flint
77
6
7
12.5
14-16
Nrf
Nrf
TD 266
dent
75
9
8
17.5
14-16
Rf
Nrf
TD 267
dent
76
6
4
15.5
18
Rf
Nrf
TD 275
dent
74
10
5
17.5
14
Rf
Nrf
TC 350
dent
74
6
4
13.5
18-20
Rf
Nrf
Inbred lines developed from backcross progenities
TD 270
dent
80
0
5
17.0
12-14
Nrf
Nrf
TD 271
dent
81
0
5
16.0
14
Nrf
Nrf
TB 367
flint
77
11
7
14.0
16
Nrf
Nrf
TC 314
dent
79
3
4
13.5
14
Rf
Nrf
TC 316
dent
77
2
5
14.5
14
Nrf
Rf
TC 317
dent
77
7
6
14.5
14
Nrf
Rf
TC 321
dent
77
7
7
15.5
14
Nrf
Rf
TC 327
dent
77
10
6
16.0
16-18
Rf
Nrf
TC 328
dent
77
2
4
11.5
18
Rf
Nrf
TC 330
flint
88
6
6
13.5
20-22
Rf
Nrf
TC 335 
dent
80
2
8
11.0
14-16
Rf
Nrf
TC 357
dent
81
2
4
14.5
14
Rf
Nrf
TC 362
dent
75
2
9
12.0
18-20
Rf
Nrf
TC 365
dent
73
0
7
14.0
18-20
Nrf
Nrf
Inbred lines developed from hybrids
TC 240
dent
75
3
7
11.0
14-16
Rf
Nrf
TC 241
dent
74
5
8
11.5
16
Rf
Nrf
TD 235
flint
75
4
6
13.5
14
Rf
Nrf
TC 322
dent
79
6
3
14.0
16
Rf
Nrf
TC 344
dent
81
2
5
15.0
18
Nrf
Nrf
TC 373
dent
81
0
5
15.5
16
-
Nrf
TC 386
dent
76
3
7
15.0
14-16
-
Nrf
TC 380
dent
77
4
8
14.5
16
Rf
Nrf
TC 390
dent
78
0
8
15.0
16
-
Nrf
TC 381
dent
77
4
4
14,5
14-16
Rf
Nrf
Nrf = non-restorer; Rf = pollen-fertility restorer; pRf = partial pollen-fertility restorer

Table 3. General combining ability of some elite inbred lines.
 
  No. Mean yield % mean of erect plants % mean of dry matter Synthetic index
Pedigree hybrids q/ha %/check % %/check % %/check %/check
1556-5-1 198 83.7 97 84 91 79.0 104 97
5471-1-1 104 91.5 101 91 99 78.9 104 103
3309-1-4 287 95.8 100 95 103 75.3 100 102
3309-4-2 125 89.0 101 95 102 77.4 102 104
3309-5-1 46 87.1 95 91 1o2 78.3 103 100
2066-1-2 18 94.3 99 88 118 75.7 101 118
1208-2-1 296 91.7 104 89 98 76.0 101 102
4818-1-1 43 101.1 103 96 106 75.5 99 106
5370-2-1 33 101.1 102 97 106 75.5 98 106
4123-2-1 62 93.8 100 92 109 77.0 101 110
4173-3-3 46 100.5 107 89 98 76.6 99 103
4176-2-2 19 103.0 105 86 98 76.9 99 1o3
2075-1-1 25 97.3 102 88 111 76.1 103 116
4256-1-1 36 94.7 101 93 110 76.1 98 109
3363-2-1 44 95.5 102 91 115 79.0 102 118
3123-2-5 244 91.3 103 94 103 76.0 101 106
3244-7-4 43 94.0 108 88 101 75.1 99 108
1148-1-1 239 90.4 104 93 101 76.5 101 106
5743-3-1 22 104.8 107 95 103 77.0 100 109

 
 
 

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

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