COLLEGE STATION - People smell them, thump them and eyeball their shape. But ultimately, it's sweetness and a sense of healthy eating that lands a melon in a shopper's cart.

Plant breeders now have a better chance to pinpoint such traits for new varieties, because the melon genome with hundreds of DNA markers has been mapped by scientists with Texas AgriLife Research. That means tastier and healthier melons are likely for future summer picnics.

"This will help us anchor down some of the desirable genes to develop better melon varieties," said Dr. Kevin Crosby, who completed the study with Drs. Soon O. Park and Hye Hwang. "We can identify specific genes for higher sugar content, disease resistance and even drought tolerance."

Melons -- they come in all sizes, shapes and colors. People around the world love them. Researchers at Texas AgriLife Research have mapped the melon genome with hundreds of DNA markers. Credit: Texas AgriLife Photo by Kathleen Phillips

The results are reported in the Journal of the American Society of Horticultural Sciences.

Melons are fleshy, edible cucurbits grown worldwide in a multitude of varieties. Not only are they economically important, the scientists noted, but they are a favorite among consumers internationally.

The average person in the U.S. eats about 25 pounds of melon every year, according to the Agricultural Marketing Resource Center at Iowa State University.

Scientists from France and Spain already had completed partial maps of segments of the melon DNA sequence. The Texas researchers connected those segments with new findings in their study to complete the entire melon genome map.

For the study, the Deltex ananas melon was crossed with a wild melon called TGR 1551. More than 100 of the offspring from that cross were grown in the AgriLife Research greenhouses at Weslaco, Crosby noted.

DNA was extracted from leaf tissue collected 21 days after planting. Results from these tests were integrated into partial maps created by other researchers.

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A University of Colorado at Boulder research team has discovered the first definitive evidence of shorelines on Mars, an indication of a deep, ancient lake there and a finding with implications for the discovery of past life on the Red Planet.
 

This is reconstructed landscape showing the Shalbatana lake on Mars as it may have looked roughly 3.4 billion years ago. Data used in reconstruction are from NASA and the European Space Agency. Image credit: G. Di Achille, University of Colorado

Estimated to be more than 3 billion years old, the lake appears to have covered as much as 80 square miles and was up to 1,500 feet deep -- roughly the equivalent of Lake Champlain bordering the United States and Canada, said CU-Boulder Research Associate Gaetano Di Achille, who led the study. The shoreline evidence, found along a broad delta, included a series of alternating ridges and troughs thought to be surviving remnants of beach deposits.

"This is the first unambiguous evidence of shorelines on the surface of Mars," said Di Achille. "The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago."

A paper on the subject by Di Achille, CU-Boulder Assistant Professor Brian Hynek and CU-Boulder Research Associate Mindi Searls, all of the Laboratory for Atmospheric and Space Physics, has been published online in Geophysical Research Letters, a publication of the American Geophysical Union.

Images used for the study were taken by a high-powered camera known as the High Resolution Imaging Science Experiment, or HiRISE. Riding on NASA's Mars Reconnaissance Orbiter, HiRISE can resolve features on the surface down to one meter in size from its orbit 200 miles above Mars.

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A University of Colorado at Boulder team has uncovered an ancient and previously unknown Maya agricultural system -- a large manioc field intensively cultivated as a staple crop that was buried and exquisitely preserved under a blanket of ash by a volcanic eruption in present-day El Salvador 1,400 years ago.

CU-Boulder anthropology Professor Payson Sheets and his team uncovered a manioc field one-third the size of football field buried under 10 feet of ash by the eruption of a volcano about 1,400 years ago that blanketed the Mayan farming village of Ceren in El Salvador. Image courtesy University of Colorado

Evidence shows the manioc field -- at least one-third the size of a football field -- was harvested just days before the eruption of the Loma Caldera volcano near San Salvador in roughly A.D. 600, said CU-Boulder anthropology Professor Payson Sheets, who is directing excavations at the ancient village of Ceren. The cultivated field of manioc was discovered adjacent to Ceren, which was buried under 17 feet of ash and is considered the best preserved ancient farming village in all of Latin America.

The ancient planting beds of the carbohydrate-rich tuber are the first and only evidence of an intensive manioc cultivation system at any New World archaeology site, said Sheets. While two isolated portions of the manioc field were discovered in 2007 following radar work and limited excavation, 18 large test pits dug in spring 2009 -- each measuring about 10 feet by 10 feet -- allowed the archaeologists to estimate the size of the field and assess the related agricultural activity that went on there.

Sheets said manioc pollen has been found at archaeological sites in Belize, Mexico and Panama, but it is not known whether it was cultivated as a major crop or was just remnants of a few garden plants. "This is the first time we have been able to see how ancient Maya grew and harvested manioc," said Sheets, who discovered Ceren in 1978.

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