SEEDLING TRAITS IN MAIZE FAMILIES DERIVED FROM A POLYEMBRINIC POPULATION

Abstract

The heritable trait polyembryony in maize (Zea mays L.) is suitable for special breeding purposes because of its effect on seed prolificacy and grain nutrimental quality. This work reports the performance of 15 d old seedlings on germination, polyembryony, seedling abnormalities and the effect of crossing direction in the full sib family group. Three types of family structures (selfed, S1; half sibs, HS; and full sibs, FS) were derived from a polyembryonic maize population named UA-IMM-NAP during the Spring-Summer 2005 in Saltillo, Coahuila, México. The families (403 S1, 330 FS and 169, HS) were represented by a random sample of 30 seeds which were sown in germination boxes, and evaluated 15 d afterwards. The experiment was done using a completely randomized design with unbalanced data, and assuming a random model regarding the family genotypes. Results showed that the HS group was the highest (P < 0.01) in germination (95 %), polyembryony (63 %) and seedling normality (90 %). The inbreeding of S1 depressed the average values and did not produce any increase in polyembryony frequency; however, it was effective to uncover genotypes with most deleterious genes. When FS direct vs. reciprocal crossings were compared, differences (P < 0.05) were detected in polyembryony, with 64% for direct crosses and 56 % for reciprocal crosses.