Three Cybonnet rice x wild introgression libraries evaluated for yield and yield components

Authors: Eizenga, Georgia

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/13/2020
Publication Date: 11/13/2020
Citation: Eizenga, G.C. 2020. Three Cybonnet rice x wild introgression libraries evaluated for yield and yield components. Abstract. ASA-CSSA-SSSA Anual Meeting, Virtual. November 9-13, 2020.

Interpretive Summary:

Technical Abstract: Cultivated rice (Oryza sativa L.) has two strongly diverged varietal groups, Japonica and Indica domesticated from the wild relative, O. rufipogon (O. nivara). To expand the diversity in the cultivated rice gene pool, six cultivated x wild introgression libraries (n=63 to 81 lines/library) were developed using three diverse O. rufipogon accessions from China, Laos and Indonesia as donors, crossed to Cybonnet, a U.S. tropical japonica long grain cultivar, and IR64, an IRRI long grain indica cultivar. All libraries were genotyped with 7K SNPs using the C7AIR array and together the introgression lines (ILs) are chromosome segment substitution line (CSSL) libraries. Previous studies of yield and yield-related traits mapped in four different cultivated rice x O. rufipogon (IRGC105491) advanced backcross populations revealed five co-located regions where 33 to 56% of the favorable QTL were attributed to the O. rufipogon allele. The objective of this study was to evaluate the three Cybonnet libraries for yield and yield-related traits to further delineate the chromosome regions (genes) associated with improved yield. Field grown ILs were evaluated for five agronomic, six panicle architecture, four seed traits, and two yield traits in 2019. Compared to Cybonnet, 12 ILs had significantly higher yield (seed weight/panicle) and two ILs had greater 100-seed weight. Among these 14 ILs, significant differences from Cybonnet were noted for seed size traits and flag leaf width. A survey of 32 ILs with wild introgressions in the region of known genes for seed size on chromosomes 2, 3, 5, 7 or 8, identified 14 ILs with introgressions on chromosome 2, 3, 7 or 8 that were significantly different from Cybonnet for seed size. Identifying only 14 ILs with potential yield-enhancing wild introgressions suggests additional wild introgressions may be necessary to realize the higher yield previously reported. Results from the 2020 field trial are pending.