Maize Genetics
Cooperation Newsletter vol 86 2012
Dickinson, North Dakota, USA
Identification
of multiple aleurone in CG Coroico
Flour
P. Puga1 and F. Kutka2
1Department
of Agriculture and Technical Studies, Dickinson State
University
2NDSU Dickinson Research
Extension Center
The
aleurone layer in maize seeds consists of the single,
outermost layer of endosperm cells just below the pericarp. Maize populations with seeds exhibiting aleurone layers of 2-4 cell layers or more were found among
the Coroico/Piricinco
racial complex from Bolivia and Peru (Figure 1; Welch et al., 1993; Wolf et
al., 1972). This multiple aleurone trait is controlled by a single, partly dominant
gene and kernels with the trait have been found to be substantially higher in
protein and mineral content, making the trait useful for the nutrient
enhancement of maize.
Our
interest was in finding the extent to which existing work with Coroico germplasm has already
resulted in northern adapted populations that carry the trait. Cargill released to the USDA a temperate
adapted population called Cargill North Temperate Zone Coroico. Kannenberg and
others at the University of Guelph in Ontario selected this population for
earliness and released it as CG Coroico Flour (Lee et
al., 2006). We examined these
populations, three Coroico/Piricinco
populations from Bolivia and Peru, three inbred lines from the Maize Genetic
Stocks Center carrying the multiple aleurone trait,
and three adapted inbreds from Minnesota and Manitoba to see how prevalent the
trait was among these sources.
Following
the methods of Welch et al. (1993), kernels were soaked in water overnight and
then sectioned with a razor blade. Sections
were stained with amido black in a 7% acetic acid
solution to improve visibility of the aleurone cells
under light microscopy. As
described by Wolf et al. (1972), the North American lines did not exhibit the
trait and few sources with the multiple aleurone
trait appeared to have the trait fixed (Table 1). Seeds with multiple aleurone
layers were found in decreasing proportions from the original Coroico, to the Cargill population, to CG Coroico Flour.
Also, when present, the second aleurone cell
layer in CG Coroico Flour seeds was largely limited
to the crown of the seeds and was usually discontinuous, unlike the original Coroico populations.
Whether this was due to a heterozygous state, the loss of modifier genes
during selection, or some other cause is unknown. However, having this trait in this early
maturing population should help plant breeders interested in using it in early
maturing cultivars.
Thanks
to Ross Welch and Margaret Smith at Cornell for the idea and methods, to Chip
Poland, Lynn Burgess, and others at Dickinson State University for staining
supplies and microscopes, and to Mark Millard at the North Central Regional
Plant Introduction Station and to Marty Sachs at the Maize Genetics Stock
Center for providing the seeds we examined.
References
Lee, E.A., F. Chakravarty, B. Good, M.J. Ash, and L.W. Kannenberg.
2006. Registration of 38
maize (Zea mays L.) breeding populations adapted
to short season environments. Crop
Science 46:2728-2733.
Welch, R.M., M.E. Smith,
D.R. Van Campen, and S.C. Schaefer. 1993. Improving the mineral reserves and
protein quality of maize (Zea mays L.)
kernels using unique genes. Plant
and Soil 155/156:215-218.
Wolf, M.J., H.C. Cutler,
M.S. Zuber, and U. Khoo. 1972. Maize with multilayer aleurone of high protein content. Crop Science 12:440-442.
Figure 1. Stained section of
kernel from Loreto 8 showing 3-4 aleurone cell layers
between the normal endosperm cells at the top and the pericarp below.
Table 1. Results of aleurone cell layer counts for selected North American and Coroico populations of maize.
|
Variety |
# Seeds Examined |
Single Layer |
Multiple Layers |
% Multiple Layers |
|
A681 |
10 |
10 |
0 |
0 |
|
A682 |
10 |
10 |
0 |
0 |
|
CM7 |
10 |
10 |
0 |
0 |
|
Stock 5708E |
10 |
4 |
6 |
60 |
|
Stock 5708F |
10 |
0 |
10 |
100 |
|
Stock 5708G |
10 |
2 |
8 |
80 |
|
Bolivia 792 |
100 |
81 |
19 |
19 |
|
Loreto 8 |
60 |
2 |
58 |
97 |
|
Coroico Composite |
99 |
54 |
45 |
45 |
|
Cargill North Temperate Zone Coroico |
96 |
73 |
23 |
24 |
|
CG Coroico Flour |
119 |
107 |
12 |
11 |
Please Note: Notes submitted to
the Maize Genetics Cooperation Newsletter may be cited only with consent of
authors.