Rice reproductive development timing i impact on kernel quality

Transcription

1 Outline for Talk Rice reproductive development timing i impact on kernel quality Paul Counce, Terry Siebenmorgen, Amogh Ambardekar and Sarah Lanning University of Arkansas Rice Processing Program Reproductive Growth Stage Timing Related Enzyme and Gene Expression Findings Practical Outputs from our Work Outline A. Reproductive Growth Stage Timing B. Enzyme activity and gene expression findings related to high night temperature effects on rice kernel quality C. Work to be done in the future REPRODUCTIVE GROWTH STAGE TIMING Greenhouse Grown Guichao and Cocodrie by Reproductive Growth Stage INDIVIDUAL GRAIN WEIGHT (mg/grain) Guichao 15 Cocodrie R-Stage of Individual Grains 1

2 Individual Kernel Growth Stage Individual kernels at each plant growth stage R8 R7 R6 R5 and below Percentage of kernels on panicles Plant Growth Stage R8 R7 R6 Yield components by growth stage Growth Stages Yield component S1-V8 Culm/ft 2 V7-V9 V9 (R1) Florets/panicle R2 MS Fertile Florets/panicle R2-R5 Grains/panicle R6 Individual Grain wt. (including grain composition and HRY) Procedure Procedure 1. Tagged culms at R2 in the ARPT at Stuttgart for 6 or 7 culms per plot in each of five cultivars, one hybrid and each of three replications Procedure Daily noted each culm for changes in growth stage from R2 through h R9 and recorded dates of Growth Stage Change Jupiter Bengal XL723 Wells LaGrue Cypress DD 5 Units R6 through R9 (27-21 Stuttgart) 2

3 Jupiter Bengal XL723 Wells LaGrue 31.7 Cypress Related Enzyme and Gene Expression Findings Days R6 through R9 (27-21, Stuttgart) Reasons to Study Enzymes Bengal HRY and Starch Synthase Enzymes build the starch molecules Understanding the enzyme processes provides a basis for understanding year to year rice functionality changes We need to better understand changes during grain filling and after grain harvest ynthase Activity e Yield (%) 3 X Starch Sy Head Rice HRY St. Synth. NIGHT TEMPERATURE º C ynthase Activity e Yield (%) 3 X Starch Sy Head Rice LaGrue HRY and Starch Synthase HRY St. Syn. X 3 RT-PCR (Gene Expression) 1. Extracted RNA from samples from the RiceTec Study 2. Probed dth the differential expression of starch synthase isoforms. 3. Noted differential gene expression for different forms of starch synthase NIGHT TEMPERATURE º C 3

4 HRY, Grain filling and Starch Synthase Head Rice Yield Grain-filling Starch Synthase Starch synthase is one component of grain-filling Grain-filling is one component of HRY HRY is affected by grain-filling, starch synthase activity and by other components 4

5 Why are night-time time air temperatures negative for HRY, chalk and functionality, as opposed to day time air temperatures. Why do night-time air temperatures negatively impact kernel quality? 1. Increasing night temperatures shortens the grain filling period and potential grain weights 2. Starch Synthase appears to be negatively impacted by HNT Our Goal: To provide practical solutions to high night temperature reduction of head rice yield: Answer: Identify genes which can ameliorate the negative effects. Potential Candidates: Starch synthesis genes esp. starch synthase Practical Outputs from our Work Work to be done (Projects) 1. Main project with ARPT lines and related sampling; 2. Project tl lead by Dr. Ken Korth tht to discover genetic means of reducing impact of high night time temperatures (Both funded by Rice Board in 211) Rice Sampling in the Field 1. Continue sampling selected cultivars and hybrids at optimum grain moisture contents across locations for quality parameters 2. Sampling of individual kernels at different plant growth stages 5

6 Gene Expression Thank You Narrow Focus: Starch synthase in R6 kernels at Growth Stages R6, R7 and R8 Broad Focus: Gene Expression across a broad selection of markers 6