Diploperennial teosinte introgressed population of maize: kernel protein content

--L. H. Perini, G. Pischedda and J. L. Magoja

Zea diploperennis, like the other wild taxa of the genus Zea, has a high kernel protein content in relation to the cultivated maize (see MNL 59:61). The results we've obtained point out that diploperennial teosinte kernels have three times more protein than maize kernels. As was previously communicated, those progenies derived from crossings between perennial teosinte and maize keep a high protein level (MNL 59:69), but the trait dilutes while the plants look like maize, more and more, as for example, when wild germplasm introgressed populations of maize are analyzed (MNL 62:80).

Probably the high protein level of the wild relatives of maize is closely related to the little size of the kernel and the high proportion of hard endosperm. If this were absolutely true, the possibility of using these wild genetic resources to increase the protein content of maize kernels would be thrown away, as individuals combining a higher protein level with desirable yields could not be recovered.

Some previous results obtained when another perennial teosinte introgressed population of maize was studied (see MNL 62:80), pointed out that perennial teosinte germplasm produced a significant increase in the protein content and that this trait was not significantly associated with other plant, ear or kernel traits. This fact showed the certain possibility of increasing the protein content by using those wild genetic resources.

When analyzing a diploperennial teosinte introgressed population of maize (see MNL 61:65 and MNL 62:84), similar results to those previously communicated can be found (see Table). A sample taken at random constituted by ears (plants) belonging to S1 lines and full-sib families derived from this population, was employed as representative of that one. The samples were taken from the plants cultivated during the growing season 86/87 in two locations of the province of Buenos Aires: Llavallol (70 ears) and Pergamino (32 ears). The results show that the average protein content is higher than normal levels for maize. The variation is relatively wide, the trait was not affected by the location and not a single significant association among protein content and some other plant, ear or kernel traits was found.
 
Locality Mean±SD Range
Llavallol 12.0±1.9 8.6-16.0
Pergamino 12.5±1.3 9.4-14.7

It must be pointed out that the population has had an average yield of 5,500 kg/ha and that the full-sib families derived from it yielded between 2,000 and 11,000 kg/ha, when they were grown at a density of 57,143 pl/ha. Those individuals belonging to this introgressed population are prolific (2 to 4 ears/plant, average:3) and show a wide range of variation for different traits and kernels yield.

Presumably the absence of association among protein content and other traits, and the presence of families with a relatively high kernel protein content and a desirable yield, lets us suppose that diploperennial teosinte germplasm could be used to increase maize kernel protein content.


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