As reported in the last issue (MNL 59:69, 1985), in F2 progeny from hybrids between perennial teosinte (Z. perennis) and Gaspe (Z. mays ssp. mays) we find multilayer aleurone kernels. This trait may be attributed to a spontaneous mutation, as neither perennial teosinte nor Gaspe has multilayer aleurone. Kernels with multilayer (2 to 6 cell layers) have aleurone with different thickness (45.6 to 143.2 um), and this thickness is not associated with layer cell number. Multilayer aleurone shows peculiarities which were not reported in maize earlier: cells are rounded, with non uniform size and thin walls. Multilayer aleurone, in some cases, invaginates inside underlying tissue.
In order to determine whether different types of aleurone have some influence on kernel proteins, protein and tryptophan contents were determined in F2 kernels from hybrids between perennial teosinte and Gaspe (Table 1). As we can see the number of aleurone cell layers has no influence on protein quality, but it does on protein content: more cell layers increases protein content of the whole kernel, significantly. In order to associate this trait with other kernel qualitative characters, 108 F2 kernels were classified, using the following traits: number of aleurone layers (ALN) single (1), single and double (2), multiple (3); endosperm hardness (EH) floury (1), predominantly floury (2), intermediate (3), predominantly flint (4), flinty (5); pericarp color (PC) pale (1), pale brown (2), brown (3), dark brown (4); pericarp surface (PS) smooth (1), intermediate (2), wrinkled (3).
Data in Table 2 show that the number of aleurone layers is strongly associated with PC and PS: multilayers appear more frequently in kernels with dark pericarp and wrinkled surface. In addition ALN is inversely associated with EH: multilayer appears frequently in kernels with a higher ratio of floury endosperm.
A new classification from a sample of 208 F2 kernels according to their aleurone layer type (single or multiple) and their endosperm type (hard= normal or completely floury) gave the data in Table 3.
According to these results we can deduce that a single recessive gene would condition multilayer aleurone trait and its spontaneous appearance may be due to mutagenic effect of hybridizing maize and teosinte as Mangelsdorf (1958) has postulated. Finally, it is important to remark that multilayer trait segregates independently from endosperm type (floury or flinty).
L.M. Bertoia and J.L. Magoja
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