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Chapter 2,399

Heterotic patterns of eighty-eight white subtropical CIMMYT maize lines

Vasal, S.K.; Srinivasan, G.; Han, G.C.; Gonzalez, C.F.

Maydica 37(4): 319-327

1992


ISSN/ISBN: 0025-6153
Accession: 002398076

Eighty-eight inbred maize lines derived from 6 CIMMYT subtropical maize populations and pools were crossed to 4 tester lines (one each from Pool 32 and Populations (Pop.) 34, 42 and 44). The 352 line X tester hybrid combinations were divided into 4 sets, each comprising crosses of 22 lines with the 4 testers, and evaluated over 2 seasons at Tlaltizapan, Mexico, during 1989-90. Mean grain yields for the 4 sets ranged from 9 (set 1) to 8.2 t/ha (set 4). GCA and SCA for grain yield were calculated by line X tester analysis. Of the 88 lines tested, 14 from Pop. 44, 11 from Pop. 42, 9 from Pool 32 and one from Pop. 34 had positive GCA effects for grain yield. Among testers, Testers 2 (Pop. 44) and 1 (Pool 32) showed positive and negative GCA effects for yield, respectively. Significant differences were observed for SCA effects for yield in the different line X tester crosses. Several combinations had yields of 10 t/ha or more and possessed high SCA effects. Interpopulation crosses generally outyielded and had greater SCA effects than intrapopulation crosses. Superior intrapopulation combinations, however, were observed among crosses involving lines from Pop. 44. Several lines included in this study were announced as CIMMYT maize lines (CML) during 1991. Twelve of the 20 top-yielding single crosses (5 from each set) were between CML lines.

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