First division restitution

Figure 2.3 All genetic interactions from the centromere to the first crossover are transmitted to offspring in gametes produced by a first division restitution mechanism such as parallel spindles.

It is interesting that dramatic differences are often observed between 4x (female) X 2x and 2x (female) X 4x erosses. This is presumably beeause the diploid parent in a 4x X 2x eross produees 2n pollen via a first division restitution meehanism, while that in a 2x X 4x eross produees 2n eggs via a second division restitution meehanism. As diseussed above, the genetic consequences of first division restitution meehanism are very different than those of seeond division restitution. Offspring Ifom 4x X 2x erosses produee higher delds and tuber dry matter eontent than those from 2x X 4x erosses (Kidane-Mariam and Peloquin, 1974 Hutten et al., 1994). However, there is no differenee between the eross types for vine maturity and ehip eolor. 

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