The Line × Tester analysis is a powerful method used in plant breeding to evaluate the combining ability of a set of parental lines (females) and testers (males). It helps breeders assess both general and specific combining ability. This analysis is particularly useful when breeders want to identify superior parents or combinations that can be used to develop hybrids with desirable traits such as yield improvement, disease resistance, or other agronomical advantages.
The Line × Tester analysis is typically used when you have two groups of parents: lines and testers. The goal is to identify how well each line combines with testers to produce desirable traits in their offspring. This analysis produces results that estimate general combining ability (GCA) for the lines and testers, as well as specific combining ability (SCA) for the crosses. GCA indicates the average performance of a parent across all combinations, while SCA highlights the performance of specific line-tester combinations.
Interpreting the results of Line × Tester analysis helps breeders select the best parental lines for future breeding programs. A higher GCA indicates that a parent consistently contributes positive traits to its offspring, while significant SCA values suggest that specific parental combinations may outperform others in terms of hybrid vigor.
In Line × Tester analysis, we have testers (males) and lines (females) as parents and their crosses. OPSTAT provides the analysis for both parents included and excluded. Arrange the data for crosses (if parents are not included) and parents as well as crosses (if parents are included), i.e., parents followed by crosses. Arrange the crosses of line-1 with all the testers, line-2 with all the testers, and so on.
Enter the data in such a way that all the replications for parent 1 must fall in the first line and are delimited by space or tab. Similarly, enter the data for the second parent in the next line, and so on. After entering the data for parents, enter the data for crosses. Enter the data for the second character just after the first, exactly in the same manner as explained above. The data file will look something like the example shown below. After entering the data, save this file. It will be used as the input file by OPSTAT.
Sample Data arrangement for Line × Tester Analysis (5 Lines and 3 Testers) is as under:
R1 R2 R3 R4
L1 104.86 84.32 76.92 76.48
L2 88.02 106.54 89.82 108.68
L3 77.94 71.34 77.52 69.48
L4 80.82 106.52 83.28 95.92
L5 59.96 52.48 52.98 50.98
T1 96.44 98.82 99.14 107.16
T2 91.44 99.66 83.28 89.46
T3 91.78 84.82 69.92 81.48
L1 x T1 74.4 70.86 60.94 68.00
L1 X T2 91.82 99.18 118.88 120.68
L1 x T3 48.08 62.1 58.54 41.84
L2 x T1 59.06 65.62 81.62 86.76
L2 x T2 84.16 109.74 102.14 94.52
L2 x T3 96.92 91.44 79.86 74.38
L3 x T1 109.86 98.16 93.26 102.26
L3 x T2 117.2 100.28 116.16 112.52
L3 x T3 109.68 116.48 123.92 120.86
L4 x T1 103.14 109.66 90.98 119.4
L4 X T2 53.4 60.86 74.46 69.08
L4 X T3 53.86 48.3 40.64 44.62
L5 X T1 98.46 73.1 89.18 75.86
L5 X T2 81.36 72.82 89.82 83.74
L5 X T3 86.62 94.18 90.32 108.16
Please Enter the numeric data only after properly arranging it as per above mention example. and it will look like:
104.86 84.32 76.92 76.48 88.02 106.54 89.82 108.68 77.94 71.34 77.52 69.48 80.82 106.52 83.28 95.92 59.96 52.48 52.98 50.98 96.44 98.82 99.14 107.16 91.44 99.66 83.28 89.46 91.78 84.82 69.92 81.48 74.4 70.86 60.94 68 91.82 99.18 118.88 120.68 48.08 62.1 58.54 41.84 59.06 65.62 81.62 86.76 84.16 109.74 102.14 94.52 96.92 91.44 79.86 74.38 109.86 98.16 93.26 102.26 117.2 100.28 116.16 112.52 109.68 116.48 123.92 120.86 103.14 109.66 90.98 119.4 53.4 60.86 74.46 69.08 53.86 48.3 40.64 44.62 98.46 73.1 89.18 75.86 81.36 72.82 89.82 83.74 86.62 94.18 90.32 108.16
The analysis of the Line × Tester design can be performed by following these steps: