EVALUATION OF SOME PROMISING TEOSINTE HYBRIDS AND THEIR GENETIC BEHAVIOR FOR FODDER YIELD

Although the need for increased production of summer fodder is so keenly
felt in Egypt, the plant breeders did not focused much of their attention to improving
fodder teosinte. In this study an attempt was made in order to partition the genetic
variance to its components for fodder traits through the evaluation of different
generations (P_l, P_z, F I, F₂, BC_l and BC_z) of the promising hybrids of teosinte.
Significant differences among crosses for number of tillers per plant, green
fodder yield per plant and crude protein percentage were detected in the three cuts.
Also, the results revealed that the presence of highly significance among populations
within crosses and populations within each cross with respect to all studied traits in
three cuts. These results reflected the diversity and the different genetiC constitution of
parental lines of the studied crosses. Furthermore, years, crosses by years and
populations within crosses by years in addition tw populations within each cross by
years mean squares were significant in most of occasions. This indicates that these
populations gave different performances at different environmental conditions. The
best combination for fodder yield components was Guatemala )( Balsas, which
showed the highest means for most of studied traits through the three cuts compared
by other two crosses as well as their parents. In this hybrid (Guatemala x 8alsas), the
values of dominance gene effe~ts were higher in magnitude than the corresponding
values of additive gene effects for all studied traits in most of cuts. This finding
reflected the presence of heterotic effect and the higher frequency of dominance
genes controlling these traits in this cross. Therefore, the means of the Fz generation
appeared to be less than the F, hybrids for most of studied fo<lder traits through the
three cuts. Regarding to Rayana x Balsas and Central plateau x Balsas hybrids, F2
generations appeared to be higher in means than their respective F I hybrids in most
of studied traits in the three cuts. These results may be due to the presence of
Iransgrassive segregations and the major role of additive as well as additive by
additive gene action in the inheritance of fodder yield components with respect to
these two hybrids. The means of most backcrosses strongly tended to be toward the
respective recurrent parents, reflecting the role of additive and epistasis gene effects.
Furthermore, the results showed that most of studied traits were significantly
influenced by one or more type of epistasis effects, which included additive K additive,
additive" dominance and dominance )( dominance gene effects as appeared in the
three studied crosses, indicating the role of non-allelic interaction in the genetic
expression of fodder traits. Number of tillers per plant was strongly associated with
number of leaves per plant, green fodder yield per plant and dry fodder yield per plant
at genetiC level.
In conclusion, the improvement of fodder yIeld in teosinte is possible through
the direct production of F I hybrids, such as Guatemala x Balsas or using these
crosses to initiate the selection program for producing superior lines for their
combining ability using the number of IHlers per plant as morphological marker.