The gene for early maturation of barley dominates over the gene for late maturity.

The gene for early maturation of barley dominates over the gene for late maturity. By crossing late-maturing barley with early-maturing, 132 early-maturing and 128 late-maturing offspring were obtained. What are the genotypes of the parents and offspring?

Let’s designate the gene that determines the late ripening of barley grains as k, then the gene that determines the early maturity of this plant will be designated as K.

In the offspring, a split corresponding to a ratio of 1: 1 was obtained, which is typical for the situation of the so-called analyzing crossing, which consists in crossing a heterozygote with a homozygote for a recessive trait.

Late-ripening barley, which has the kk genotype and produces the same type of germ cells, k, acts as a homozygote for a recessive trait.

Early ripening barley, giving splitting according to the timing of grain ripening in the offspring, must be heterozygous. Let us denote it, according to the introduced notation, as Kk. Such barley is capable of producing two types of germ cells – K and k.

The offspring are represented by the following possible options:

homozygous barley with late grain ripening (kk) – 50%;

early maturing heterozygous barley (Kk) – 50%.

The theoretically obtained percentage corresponds to the actual numerical values ​​from the condition of the problem, which confirms the assumption.

Answer: early ripening barley is heterozygous (Kk), late ripening is homozygous for the recessive gene (kk).