Not long after cloning the gene, Jackson had a group of gifted Long Island high school students, part of a program called Partners for the Future, perform an analysis of literally thousands of maize ears. Their task was to meticulously count the number of rows of kernels on each ear. It was part of a research project that won the youths honors in the Intel Science competition. Jackson, meantime, gained important data that now has come to full fruition.
The lab's current research has now shown that by producing a weaker-than-normal version of the FEA2 gene one whose protein is mutated but still partly functional -- it is possible, as Jackson postulated, to increase meristem size, and in so doing, get a maize plant to produce ears with more rows and more kernels.
How many more? In two different crops of maize variants that the Jackson team grew in two locations with weakened versions of FEA2, the average ear had 18 to 20 rows and up to 289 kernels as compared with wild-type versions of the same varieties, with 14 to 16 rows and 256 kernels. Compared with the latter figure, the successful FEA2 mutants had a kernel yield increase of some 13%.
"We were excited to note this increase was accomplished without reducing the length of the ears or causing fasciation a deformation that tends to flatten the ears," Jackson says. Both of those characteristics, which can sharply lower yield, are prominent when FEA2 is completely missing, as the team's experiments also demonstrated.
Teosinte, the humble wild weed that Mesoamericans began to modify about 7000 years ago, beginning a process that resulted in the domestication of maize, makes only 2 rows of kernels; elite modern varieties of the plant can produce as many as 20.
A next step in the research is to cross-breed the "weak" FEA2 gene v
|Contact: Peter Tarr|
Cold Spring Harbor Laboratory