S 2- lines testing for inbred extraction and hybrid production in high oil corn (Zea mays L.)
1985
Suniratana Jongmee
Alexander high oil corn variety was selfed for two generations (S2) and selection was based on their agronomic characters and oil contents. The selected S2 lines were analysed for their oil and starch percentage to study correlation between oil and starch percentage. The other selected S2 lines were testcrossed to three inbred testers, i.e. Ki 3, Ki 11 and Ki 20. The testcrossed progenies were arranged in yield trial and analysed for their oil contents. The results revealed that reduction of oil content in the S2 generation was lower than that in the S1 generation. However, oil content increased in the testcross generation. There was a negative correlation between oil and starch percentage with highly significant differences. General combining ability of Ki 11 was highest in oil content but lowest in yield while the general combining ability of Ki 20 was the highest in yield but the lowest in oil content. Seven S2 lines that possessed high yield with moderate high oil content were selected based on the average performances across all three testers. They were AHO 19-1-3-3, HO 1-3-5-2, AHO 19-1-1-2, HO 1-16-2-1, AHO 19-1-1-1, AHO 19-1-4-1, DA(HO)8-1-2-2*. Ten S2 lines were kept on the basis of high specific combining ability in both traits. They were AHO 19-1-4-3*, DA(HO) 8-1-4-2*, DA(HO) 8-1-2-2*, HO 1-3-5-2, HO 1-16-2-1, AHO 19-1-5-2, AHO 21-1-3-3, AHO 21-2-1-2, HO 1-2-1-2 and AHO 21-1-1-2. (* refer to S2 lines that are not treated with Apron). Three S2 lines were high in both general and specific combining abilities. There were fourteen S2 lines kept at the selection intensity of about 25 percent.
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