Reciprocal Effect of Parental Lines On Corn Hybrid Seeds Performance.

In the corn crop (Zea mays L.), obtaining high quality seeds is closely related to heterosis and the use of compatible parental lines contributes to the increase of this phenomenon. In this regard, it must be considered the reciprocal effect of parental lines used in a cross, since certain characteristics are controlled by cytoplasmic genes and is inherited from the maternal lineage. Thus, this research aimed to study the reciprocal effect of parental lines on the physiological potential of corn hybrid seeds. Twelve corn hybrid seeds (HS 12, HS 13, HS 14, HS 21, HS 23, HS 24, HS 31, HS 32, HS 41, HS 42, HS 51, HS 52) were initially evaluated and after three months by germination, vigor (first count of germination, cold test, accelerated aging and electrical conductivity) and seedling emergence in the field tests. According to the initial characterization, HS 23, HS 24 and HS 41 crosses showed high vigor and HS 13, HS 15 and HS 52 were considered low vigor hybrids. Based on this analysis, it is not evident the relationship between vigor and reciprocal effect of parental lines. However, after three months of storage, it was verified that the HS 14 cross decreased its vigor, as evidenced by the results of first count of germination, accelerated aging and electrical conductivity tests. These results were also confirmed by the seedling emergence in the field test, which indicates the real performance of the hybrids. This behavior may indicate reciprocal effect of parents L1 and L4, once the physiological potential of the lots containing these lineages in the crosses, sometimes as female, sometimes as male parent, was different. Thus, the L1 lineage should be used as male parent, so that does not incur in a reduction of seed vigor of the crosses that use this lineage.