DIALLEL AMONG 28 VARIETIES OF MAIZE

Twenty eight varieties of maize of different maturities and types of e ndosperm were assessed together with 378 F-1, and seven commercial hyb rids (controls) in three locations: Sete Lagoas, MG, Goiania, GO, and Londrina, PR. The varieties represent germplasms adapted to different areas of Brazil, used in the breeding program at the National Maize an d Sorghum Research Center at Sete Lagoas, MG. The joint analysis of va riance for ear weight showed significance (P < 0.01) for environments, entries, varieties, heterosis, mean heterosis, variety heterosis, spe cific heterosis, environments x entries and environments x varieties. The average yield of the varieties varied from 2,322 to 7,704 kg/ha, w hile for the intervarietal hybrids the variation was from 4,112 to 8,3 63 kg/ha. The mean heterosis was 489 kg/ha and the varietal heterosis varied from -589 to 1,339 kg/ha. The highest specific heterosis was ob tained for the BR 105 x BA III - Tuson crossing. Some intervarietal hy brids were higher yielding than the best control. This is promising fo r breeding purposes, since new synthetic varieties can be formed or us ed to begin programs to produce hybrids. No association was found betw een heterosis and endosperm type.