WASHINGTON - A new research on the evolution of maize may help improve crop yields in the future.

As one of the most important crops worldwide and as a crop that appears very different from its wild relatives as a result of domestication, understanding exactly how maize has evolved has many practical benefits and may help to improve crop yields.

The research, done by Dr. Marina Dermastia and colleagues, compared corn kernel development to its closest wild relative: teosinte.

This research overturns some commonly held beliefs on the domestication of maize because, unexpectedly, many traits seen in the cellular development of maize kernels that were previously attributed to the process of domestication were observed in the development of the teosinte kernels by Dermastia and her colleagues.

“Although the teosinte kernels are morphologically so different from that of maize, their inside is not,” Dermastia said.

“Although we did not expect fundamental differences between maize and teosinte, the similarities were striking,” she added.

Some of the traits thought to be unique to maize but now also found in teosinte include an early-programmed cell death for cells in part of the kernel and accumulation of phenolic and flavonoid compounds in the walls of these cells.

These developmental changes strengthen the cells, protect them against decay and disease, and increase water conductance.

The presence of these traits in teosinte kernels suggests that they are not a consequence of maize domestication.

Dermastia and her colleagues did observe one difference between seed development in teosinte and maize.

Endoreduplication, the process of a cell duplicating its DNA without subsequent cell division, is a phenomenon that occurs in the endosperm of cereals, which is the nutritious part of the seed.

An increasing rate of endoreduplication results in cells with greater DNA content and, subsequently, increased gene expression and greater sink capacity for the developing seed.

Dermastia and her colleagues observed that the distribution of cells with high DNA content in maize differs from that of teosinte.

In maize, these cells are found in the upper part of the endosperm, while in teosinte they are distributed throughout the endosperm.

The researchers hypothesize that this difference may be related to more efficient starch deposition in maize as a result of domestication.

“Our study indicates that the main differences, beside the teosinte fruitcase and its absence in maize, might lay in the process of endoreduplication in endosperm,” Dermastia said.

“Knowing the process in more depth might be an important step in improving a most important crop,” she added. (ANI)