It is evident that F₁ hybrid of the cross Panonja x Dardo encloses the limits between the two parental forms.

When backcrossed with the high protein containing parent Panonja, the protein in BCP₁ population reached 17%, its level being considerably above the levels of F₁ and the high protein containing parent Panonja. The average value for the protein in F₂ surpassed the capacities of F₁ and Pannoja variety, which was obviously due to the transgressive form. As it is presented in the Figure, F₂ population was distinguished for its greater variability. Its limits were from 12% up to 19% protein, 14% of the individuals having higher protein content than Panonja variety.

The results obtained from the backcross with the high protein containing parents of the two crosses tested - San Pastore x Bezostaya 1 and Panonja x Dardo - and F₂ population of the cross Panonja x Dardo showed greater inheritance intensity of the genes conditioning the higher protein content of Bezostaya 1 and Panonja, and also the suppressive effect on the genes determining the lower protein content in San Pastore and Dardo varieties. This was also confirmed by the backcrossing with the low protein containing parent Dardo in the cross Panonja x Dardo, in which the level of BCP₂ population did not go below the level of F₁.

In all two crosses contrasting in grain protein content, the level of the population became higher than F₁, when backcrossing with the high protein containing parent. It set up at the level between F₁ and the level of the high protein containing parent or at its own level.

As it is shown in Table 1, the cross Valdichiana x San Pastore was a cross between varities, differing in grain protein content too, though at a smaller degree.

In F₁ of the cross Valdichiana x San Pastore the low protein content was dominant.

When backcrossing with the high protein containing variety Valdichiana, the level of BCP₁ population did not become higher than the level of F₁ but it remained almost at the level of the low protein containing San Pastore.

The limits of variability for BCP₁ and BCP₂ populations were the same as for F₁ (Fig. 2).

The variability of F₂ hybrids of the cross Valdichiana x San Pastore was relatively greater than F₁, BCP₁ and BCP₂ but it did not go beyond the limits of the parental varieties.

The results obtained for the protein in the cross Valdichiana x San Pastore indicate the smaller inheritance intensity of the genes, conditioning the high protein content of Valdichiana variety.

Through the method of backcrossing with the high protein containing parent, better conditions are created for the successful selection of high protein containing varieties. To a great extent, however, this depends on the inheritance intensity of the genes conditioning the high protein content in the varieties used for hybridizatoin.

(Received April 30, 1974)