Critical Roles of the Puerto Rico Winter Nursery in the Southern US Rice Breeding Programs.

Rice is one of the important crops in the Mississippi delta and coastal Louisiana and Texas. About three quarters of US rice is produced in the Mid-South including Arkansas, Louisiana, Mississippi, Missouri, and Texas. Rice breeding programs in these states as well as USDA-ARS Dale Bumpers National Rice Research Center rely on the winter nursery at Lajas, Puerto Rico for generation advancement, seed purification and increase, germplasm propagation and rejuvenation of the USDA world collection.

Established in 1970 by Louisiana State University in a cooperative agreement with the University of Puerto Rico, the nursery is located at the University of Puerto Rico’s Agricultural Experiment Station at Lajas and managed by the station personnel. Since then, USDA-ARS and public breeding programs at University of Arkansas, Mississippi State University, Texas A&M University have joined the cooperative agreement, which makes the winter nursery more cost effective and accessible. Currently, there are about 70 acres of land dedicated to the rice nursery and accessible to the participating institutions and other companies. Significant improvements on land leveling, irrigation and drainage, small machineries of planting, harvesting, and spraying, as well as drying facilities allow timely planting, harvesting, and processing of the breeding materials and small seed increases. Under the tropical climate, one to two extra generations of rice can be grown and harvested, which results a 1-3 years’ reduction in the variety development cycle. Almost all the rice cultivars released in the Southern US since early 1980s went through at least one generation at the winter nursery. With the recent launch of the public hybrid rice breeding program, Puerto Rico winter nursery will continue to play an important role in the development of rice cultivars and hybrids in the Southern US.