Contents

Science Update

Is Cottonseed a Good Choice for Bull Diet?

Beef producers may want to limit the amount of cottonseed, a popular ingredient in cattle and sheep feed, in diets fed to their young breeding bulls. Some producers have already taken such action. They learned of studies—including a 6-½-month feeding trial—by scientists at ARS and the Texas Agricultural Experiment Station at Overton. From weaning time through puberty, scientists fed young bulls a diet containing whole cottonseed or cottonseed meal. At the end of the trial, they found damage to sperm-producing germ cells in these bulls. Cottonseed contains gossypol, a pigment in cotton plants. Gossypol has been linked to infertility in men and testicular tissue damage in mature bulls and rams. Processing can render gossypol harmless in products such as cottonseed oil and meal.

Chad C. Chase, Jr., USDA-ARS Subtropical Agricultural Research Station, Brooksville, Florida, phone (352) 796-3385.

Why Melons Go Bland

Consumers like their cantaloupe sweet, not bland. Now, growers can stop blandness before it starts, because of new findings in plant physiology. Growers know heavy rains just before harvest can make cantaloupes lose sweetness—and market appeal. This need not happen, say researchers, if growers can harvest either within a day or two after the heavy rain or a week later, when the fruit's sugar rebounds. Growers have believed that sweetness is diluted by excess water taken up via roots. Scientists at ARS, North Carolina State University, and the University of Arizona learned otherwise. The real culprit is a halt in the fruit's sugar imports about 4 days after heavy rain. First, roots shut down-stressed because they can't take up oxygen from water-saturated soil. Then, they signal the leaves to stop photosynthesizing sugar. Meanwhile, sugar already in the fruit starts breaking down.

Gene Lester, USDA-ARS Crop Quality and Fruit Insects Research Unit, Weslaco, Texas, phone (956) 447-6322; Steven Huber, was in USDA-ARS Plant Physiology and Photosynthesis Research Unit, Raleigh, North Carolina, phone (919) 515-3906.

Lupin: A Cool Alternative to Soybeans

ARS and a California firm hope to ripen sweet white lupin, a legume, into a top-performing commercial crop. Lupin's fickle ripening and yield make it tricky to grow. ARS scientists are tackling the problem through a cooperative R&D agreement with Resource Seeds, Inc., of Gilroy, California. Lupin with predictable flowering and high yield would give farmers a new option in areas too cool for soybeans, a popular high-protein feed for dairy cows. Lupin's high-fiber flour can also enrich pastas, cake mixes, cereals, and other baked goods.

USDA-ARS New England Plant, Soil, and Water Laboratory, Orono, Maine, phone (207) 581-3363.

Apple Buds Snooze in Deep Freeze

To preserve genetic traits of rare and classic apple varieties, ARS scientists have for the first time stored the living buds in liquid nitrogen at -151° F. The storage method, cryopreservation, will eventually provide an emergency backup for all 2,500 apple types growing outdoors at an ARS germplasm repository in Geneva, New York. Those trees are well cared for--but vulnerable to disease, insects, ice storms, and other disasters. So far, buds of 250 apple types have been cryopreserved at ARS' National Seed Storage Laboratory in Fort Collins, Colorado. Among them: Esopus Spitzenburg, a variety from colonial times; and Lady, dating from ancient Rome. To produce new trees bearing apples true to a given variety scientists can warm up the stored buds and graft them to rootstock.

Philip L. Forsline, USDA-ARS Plant Genetic Resources Unit, Geneva, New York, phone (315) 787-2390; Leigh Towill, USDA-ARS National Center for Genetic Resources Preservation, Fort Collins, Colorado, phone (970) 495-3260.

"Science Update" was published in the March 1995 issue of Agricultural Research magazine.