2010 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research project is to operate a fall and winter rice nursery for the purpose of advancing plant generations and seed increase. 1b.Approach (from AD-416) The Dale Bumpers National Rice Research Center (DBNRRC) of the USDA, ARS, SPA will provide rice seed stock for increase and harvest the plots. The Cooperator will plant and manage the research plots during the growing season. 3.Progress Report The Puerto Rico winter nursery was successfully used to advance six rice mapping populations and other breeding materials, and rejuvenate germplasm seedstocks. Two populations, including 700 individuals that are being used to identify chromosomal regions linked with resistance genes to blast diseases, were advanced to the F6 generation. Two other populations, including 600 individuals, were advanced to F4 generation for the objective of identifying genes responsible for low arsenic concentrations in rice grain to improve nutritional value of rice. Two additional mapping populations were advanced to the F6 generation and will be used to study yield components in rice. Breeding materials included 945 F1 crosses, 83 F2 populations, and 157 parents that are being used to develop male sterile, maintainer, and restorer lines for breeding of hybrid rice in the US. Some 300 lines were evaluated for potential under low water use scenarios. Selections were made among 250 aromatic breeding lines to determine those that would be further evaluated in yield trials. A total of 350 accessions that have low seed supply in the USDA National Small Grains Collection (NSGC) of rice germplasm collection were rejuvenated. Fresh seed of these accessions were manually harvested and submitted to the NSGC in Aberdeen, ID, for public distribution to researchers. The cooperator accurately planted the materials, managed the field during the growing season, provided facilities and expertise for harvesting and processing the seed, and coordinated seed inspection with APHIS authorities prior to shipment of the seed to Arkansas. This project was monitored through quarterly phone calls and email correspondence as well as two on-site visits.