Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/3/2020
Publication Date: N/A
Technical Abstract: Since most U.S. rice cultivars are derived from the tropical japonica rice (Oryza sativa L.) genepool, understanding the genetic variation for yield related traits in this subpopulation is important to U.S. rice breeding efforts. The ‘Estrela’ × NSFTV199 recombinant inbred line (RIL) mapping population was developed from two phenotypically and genotypically diverse japonica rice accessions in the Rice Diversity Panel 1. Although the Estrela parent was initially classified as a tropical japonica, subsequent SNP genotyping reclassified it as an admixture of japonica. The NSFTV199 parent is classified as a tropical japonica. Phenotypically, Estrela is a long grain with low amylose content and high gelatinization temperature, is pubescent and has blast genes, Pi-z and Pi-ks. On the other hand, NSFTV199 is a medium grain with intermediate amylose content and intermediate gelatinization temperature, is glabrous and has the blast gene, Pi-ks. The population was phenotyped for eight agronomic traits (days to heading, plant height, flag leaf length and width, leaf pubescence, culm habit, awn presence and seed shattering), six panicle architecture traits (panicle length; number of primary branches, florets, seeds and sterile florets per panicle; and percent fertility), and nine grain traits (seed length, width, and length to width ratio with and without the hull; percent chalk in brown rice with and without the broken kernels, and 100-seed weight). For QTL mapping, 256 Estrela × NSFTV199 RILs were genotyped with 134 SSR markers and 70 QTL were found for these traits. The population exhibited transgressive variation for panicle architecture traits as well as grain traits. The objective of this study was to select RILs with panicle architecture traits that could be used to improve yield, which also had acceptable grain size, maturity, plant height and grain yield for use in U.S. breeding programs.