Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/18/2014
Publication Date: 12/10/2014
Citation: 4. Sater, H.M., Moldenhauer, K.A., Pinson, S.R.M., and Boyett, V.A. 2014. Early Screening of Recombinant Inbred Lines for Fissure Resistance in Non-Semidwarf Rice. Proc. 35th Rice Tech. Work. Group Meet., New Orleans, LA, p. 61. Feb. 18-21, 2014. CDROM. Interpretive Summary:
Technical Abstract: Rice (Oryza sativa L.) kernel fissuring poses a major problem for both rice farmers and millers. It results in the decreased value of milled rice because of the increase in the percentage of broken kernels associated with fissuring. This study employs the use of fine mapping to increase the genetic resolution of fissure resistance traits found in ‘Cybonnet’, a semidwarf tropical japonica cultivar, as well as accomplish the transfer of this trait to rice genotypes of standard plant height. The segregating progeny in this study were from a cross between a conventional inbred line with low head rice yield, and ‘Cybonnet’ which is noted for both higher head rice yield, as well as fissure resistance. Three chromosomal regions were previously reported to contain alleles associated with fissure resistance (FR). We used SSR markers within the three putative QTL regions to study additional recombination within the FR QTL linked to the semidwarf gene (sd1) on chromosome 1, known as qFIS1-2, to allow for finer mapping of this FR QTL. Preliminary screening of individuals was conducted in the F2 generation. Eleven individual plants were advanced to F2:3 based on the following criteria: 1) the individual maintained at least one standard height allele (i.e. was either Sd1Sd1 or Sd1sd1) from the inbred parental line, 2) the individual possessed recombination in the chromosomal region reportedly containing both the sd1 and a fissure resistance gene, and 3) when possible, the individual was homozygous for the two FR QTLs not linked to sd1. The F2:3 progeny will be genotyped before being phenotyped, such that only individuals found to be homozygous for the new recombination will phenotyped for FR. The phenotypic assay to confirm the magnitude of difference between genotypes will use the percent fissured grain from individual genotypes as has been done in previous fissure resistance studies. Thus, this study aims to quantify the linkage disequilibrium (cM distance) between sd-1 and qFIS1-2 as well identify plants of standard height (Sd1) now containing the desired qFIS1-2 allele.