The protein patterns of Euchlaena perennis Hitch., Gaspé line (maize) and its reciprocal F1 and F2 (MNL 52:37, 1978) were studied. It was also considered interesting to compare them with Tripsacum dactyloides.
Endosperm proteins were fractioned according to the method of Landry-Moureaux (1970). When the proteins of the maize endosperm, of E. perennis and Tripsacum are fractioned, the protein patterns which are obtained differ (Table 1). In the close relatives of maize albumins and globulins are very low. This coincides with the results found by J. W. Paulis and J. S. Wall (J. Agric. Food Chem. 25:267-270, 1977), who ascribe these differences to the small size of the germs of Euchlaena and Tripsacum. The results obtained in our work, performed on endosperm, show that there is no influence of the germ size; this smaller ratio of albumins and globulins must be the result of a specific differentiation as a consequence of genetic differences among the species.
Table 1. Endosperm protein pattern of Gaspé (Gs), Euchlaena perennis
(Ep) and Tripsacum dactyloides (Td). SS--saline (albumins, globulins);
Z--zein; G1--glutelin-1; G2--glutelin-2; G3--glutelin-3.
|Soluble nitrogen (percent of total)|
Another differential characteristic of the protein patterns studied is the high ratio of glutelin-1 in E. perennis and Tripsacum. It seems that if the ratio of glutelin-1 were a specific character, E. perennis would be genetically closer to Tripsacum than the annual species of teosinte.
Finally, other differences among the protein patterns of the three species are the different ratio of glutelin-3 (less in E. perennis and Tripsacum than in maize).
The protein patterns of the F1 endosperms obtained by the crossing of Gaspé and perennial teosinte differ according to the way of crossing (Table 2). The protein pattern found for the first F1 (Gaspé x E. perennis) shows a significant modification with respect to the maize that acted as mother. This would explain the small viability of the grains which was indicated earlier (MNL 52:37, 1978). In addition to the characteristics pointed out, the levels of glutelin-1 and glutelin-3 are similar to those of the mother line. The reciprocal F1 (E. perennis x Gaspé) presents differential peculiarities in its protein pattern. It appears that in the cross of Gaspé x E. perennis, Zea arises as dominant for the ratio of glutelin-1 and 3. In the reciprocal E. perennis x Gaspé, Zea also appears as dominant for glutelin-1, in spite of the fact that the ratio of genomes in the endosperm is 4 to 1 in favor of Euchlaena. The protein patterns of the reciprocal F2 endosperms are very similar among themselves.
Table 2. Endosperm protein pattern of Gaspé
(Gs), Euchlaena perennis (EP) and their F1 and F2 reciprocal crosses. SS--saline
(albumins, globulins); Z--zein; G1--glutelin-1; G2--glutelin-2; G3--glutelin-3.
|Fraction||Gs||Ep||Gs x Ep||Ep x Gs||Gs x Ep F2||Ep x Gs F2|
Although there is no evidence on the chromosomal behavior of both species as regards the numeric participation in the F1 gametes, it may be considered that certain maize chromosomes that carry regulatory genes which would control the relative level of the glutelin-1 fraction would be eliminated by the preferential formation of gametes. This fact would explain why the character of Euchlaena (high glutelin-1) is restored in the F2 endosperms in spite of being recessive in the reciprocal F1.
Angel Alberto Nivio and Jorge Luis Magoja
Return to the MNL 55 On-Line Index
Return to the Maize Newsletter Index
Return to the Maize Genome Database Page