ESTIMATION OF GENETIC COMPONENTS IN MAIZE (Zea mays L.) ENDOGAMIC LINES.

Abstract

The specific (SCA) and general combinatorial aptitude (GCA) are used to identify hybrid combinations between inbred lines with higher or lower yield than that expected from the average behavior of the parental lines. The objective of this study was to evaluate the GCA of eight lines and the SCA of their inbreeding. We hypothesized that crosses between lines with contrasting characteristics would produce outstanding hybrids. During autumn 2011 the crosses were formed and in spring 2012 evaluated at the Marín experimental field, Universidad Autónoma de Nuevo León, México. The eight evaluated inbred lines were in a complete blocks experimental design at random with three repetitions. Genetic analysis was performed with the design II North Carolina mating from Comstock and Robinson. The progenitors, considered as males M-16 (4.74 t ha?1 ), M-11 (4.60 t ha?1 ) and M-14 (4.21 t ha?1 ) and females H-8 (4.26 t ha?1 ), H-2 (4.15 t ha?1 ) and H-4 (4.13 t ha?1 ) showed the greatest effects of GCA. Major effects on SCA were observed in the H-8?M-16 (4.99 t ha?1 ), H-8?M-11 (4.83 t ha?1 ) and H-2?M16 (4.78 t ha?1 ) crosses. The additive variance for grain yield was 0.03 and exceeded the dominance variance (?0.34); heritability in the strict sense was 7.65 % and female variance (0.0075) was higher than that of males (0.0012).