Proceedings of the Fifth Asian Regional Maize Workshop - Search ...

seed often varies substantially because of differences in net seed
yield. For example, in Mexico an important factor determining net seed
yields is the pnoportion of usable seed, since varying amounts of
seed of unacceptable size must be discarded (Table 5).
the costs which _t be covered by the price of hybrid seed. If
hybrid seed is produced fran inbred 1ines developed by the publ ic
sector J research and development costs do not have to be ref1ected in the
price of seed.JJ Likewise, if hybrids are pranoted extensively through
public sector extension programs, marketing and pranotion costs bome by
private canpanies are generally low.
Table 5. seed yield of parent inbreds, single-cross parents, and canmercial double-cross
hybrid in Mexico, 1991.
Gross seed Net seed Net seed
yield, yield yield
Par.,t lines (t/ha) (t/ha) (tI)
M15* 2.33 0.13 5
M16 2.27 0.32 14
M17* 2.48 0.39 16
M1S 2.36 1.04 44
M17 x M1S* 0.67 0.54 80
M15 x M16 5.S6 2.00 34
OC-rcial hybrid (t/ha) (t/ha) (tI)
1+-2S** 6.50 4.73 73
Source: Lopez-Pereira and Espinosa C. (1993).
• Male parent of cross•
*. (M17 x M1S) x (M15 x M16).
the structure and