The Community of Practices “Concept applied to rice production in the Mekong Region: Quick conversion of popular rice varieties with emphasis on drought, salinity and grain quality improvement Improvement of drought tolerant variety, IR57514 , for grain aroma and cooking quality using marker-assisted selection   Ubon Ratchathani University

Background IR57514 is an elite drought tolerant and high yielding rice variety developed by IRRI which is well adapted to rainfed lowland in Mekong region where the areas are mostly limited by abiotic stresses with unpredictable rainfall patterns. BUT it was not successfully adopted by farmers due to unsatisfied of grain qualities. IR57514 + aroma + good cooking quality SOLUTION Problem ? Breeding IR57514 for grain aroma and good cooking quality traits will greatly enhance both quality and productivity of rice in the rainfed lowland areas in Mekong region.

Objective The research was aimed to improve grain aroma and cooking quality of IR57514. Marker-assisted selection (MAS) in backcross breeding will be used to transfer favorable alleles of genes / QTL of grain aroma and good cooking qualities traits from KDML105 into genetic background of IR57514.

Plant materials The marker-assisted backcross breeding was conducted using IR57514 as the recipient parent. KD571-77, the backcross introgression line of KDML105 carrying Xa21 for bacterial leaf blight resistance and Sub1A, Sub1B and Sub1C for submergence tolerance, was used as a donor parent for grain aroma and good cooking quality traits. The backcross procedure for introgression of the target QTLs was conducted at Ubon Rice Research Center and Kasetsart University, Kamphangsean Campus, Nakorn Pathom.

MAS Phase I Breeding scheme: MAS Phase II

waxy for amylose content & gel consistency, 1st workshop (May 21 – 30, 2007) 352 BC3F1 were produced from the crosses between the selected 14 BC2F1 and IR57514. 14 BC3F1 were selected based on MAS: BADH for grain aroma, waxy for amylose content & gel consistency, SNP 2341 for gelatinization temperature PB7-8 for Xa21 bacterial leaf blight resistance Phase I MAS Phase II

1640 BC3F2 plants were generated from 11 BC3F1 2nd workshop 2nd workshop (Nov 10 – 24, 2007) 1640 BC3F2 plants were generated from 11 BC3F1 The 436 BC3F2 progeny were selected from 1640 BC3F2 based on phenotype. 33 lines were selected using MAS: BADH for grain aroma, waxy for amylose content & gel consistency, SNP 2341 for gelatinization temperature PB7-8 for Xa21 bacterial leaf blight resistance characters. MAS Phase II

3rd workshop (May 1 – 15, 2008) These 33 families of BC3F2 were selfing to generate 2,595 lines of BC3F3 progeny. Marker-assisted selection (MAS): BADH for aroma waxy for amylose content and gel consistency SNP2341 for gelatinization temperature and PB 7-8 for Xa21 bacterial left blight resistance 370 BC3F3 progeny were selected based on genotype (260 lines) and based on phenotype (110 lines). The selected 370 BC3F3 progeny will be evaluated for the traits of interest comparing to the recipient variety, IR57514 . 3rd workshop MAS Phase II

Grain quality: aroma, cooking quality BC3F2 BC3F5 MAS Phase II 4th workshop (May 1 – 15, 2008) Traits Validation Grain quality: aroma, cooking quality BC3F2 BC3F5 Submergence tolerance BC3F4 Drought tolerance

Traits Validation : Grain aroma and cooking quality in BC3F2 and BC3F5 Grain Quality Grain aroma : sensory test Amylose content : colorimetric method described by Julaino (1987) Gel consistency : described by Tan et al. (1999) Gelatinization temperature : Alkaline test (alkali spreading value ) as described by Little et al. (1958)

Traits Validation : Submergence tolerance (BC3F4 and BC3F5) IR57514 KDML105 FR13A RD6 Data recording ; Percent of plant survival (PPS) Percent of plant elongation (PPE) Leaf senescence (Siangliw et al., 2003). Location : Kasetsart University, kampangsean campus, Nakorn Pathom Results 370 BC3F4 173 BC3F4 PPS PPS, LS, PPE 56 BC3F5 20 BC3F5

Submergence tolerance validation in 56 BC3F5 lines.

Validation : Drought tolerance (BC3F4) Experiment Design : Randomized Complete Block Design in CPA Augmented Design in RGDU Check varieties: IR57514  Tolerance check KDML105, KD571-77  Susceptible check Population size: 319 BC3F4 lines  Chumpae Rice Research Center 173 BC3F4 lines  Kasetsart University, Kampangsean campus Data recording  GY (Grain yield)  PH (Plant height)  PN (Panicle number)  TN (Tiller number)  FWD (Flowering date)

Grain quality genotyping and validation Final Lines Grain aroma and cooking quality testing (BC3F5 progeny) Grain quality genotyping and validation   No. # Aroma GT AC GC Lines BADH Score SNP2341 Waxy KD571-77 1 KD 5 16 73 IR57514 3 IR 2 33 102 BC3F5 # 14-34-1-16-1 KD* 4.9 19 86 BC3F5 # 22-43-1-10-19 5.0 82 BC3F5 # 22-43-1-10-24 109 4 BC3F5 # 22-43-1-10-27 20 106 BC3F5 # 22-43-1-10-32 17 108 6 BC3F5 # 22-43-1-10-44 146 7 BC3F5 # 22-43-1-42-25 22 104 8 BC3F5 # 85-4-1-24-1 123 9 BC3F5 # 85-4-1-24-12 21 131 10 BC3F5 # 85-4-1-24-41

Submergence validation (BC3F5) Drought validation (BC3F4) Final Lines Submergence tolerance and drought tolerance validation No. Lines Submergence validation (BC3F5) Drought validation (BC3F4) Grain yield (kg rai-1) Sterility (%) Flowering date PPS PPE LS Irrigated Drained KD571-77 67.98 33.81 20.14 87.68 90.46 3.61 7.18 90 88 IR57514 73.39 27.21 31.99 140.82 121.40 4.37 4.93 103 98 1 BC3F5 # 14-34-1-16-1 79.29 24.93 33.04 101.40 103.47 1.92 0.67 80 81 2 BC3F5 # 22-43-1-10-19 73.61 21.50 27.81 - 3 BC3F5 # 22-43-1-10-24 81.35 25.96 30.81 125.89 93.61 1.11 2.39 83 92 4 BC3F5 # 22-43-1-10-27 74.48 24.89 32.05 94.05 89.64 1.85 6.95 5 BC3F5 # 22-43-1-10-32 75.99 16.45 31.98 95.90 102.62 0.93 1.43 84 6 BC3F5 # 22-43-1-10-44 69.37 25.53 33.50 119.60 100.76 2.04 1.86 91 7 BC3F5 # 22-43-1-42-25 73.29 35.57 32.04 125.83 96.38 2.02 4.65 89 8 BC3F5 # 85-4-1-24-1 71.82 22.84 28.08 137.80 110.51 4.29 11.23 101 100 9 BC3F5 # 85-4-1-24-12 74.89 22.49 32.78 139.04 95.27 5.64 13.76 104 102 10 BC3F5 # 85-4-1-24-41 78.15 24.97 28.34 120.49 93.91 9.77 14.89 Mean 72.86 26.90 29.46 118.63 103.69 2.55 4.17 88.14 90.02 Prob. ** LSD0.05 2.36 1.67 0.63 1.68 1.48 0.17 0.30 0.68 0.64

Conclusion We aimed to improve grain aroma and cooking quality of IR57514 using MAS. 10 selected BC3F5 were finally selected for grain aroma and cooking quality traits based on genotype (MAS) and these lines were validated for grain quality, submergence tolerance and drought tolerance. These selected lines will be on trial both in station and on farm in rice production areas in Mekong region. Marker assisted selection (MAS) technology was an excellent tool for rice breeding program. MAS technology jointly with classical breeding will increase the effectiveness and precision of selection process. MAS will be shortening the breeding program and also reduce the cost of breeding program. Breeding IR57514 for grain aroma and good cooking quality traits will greatly enhance both quality and productivity of rice in the rainfed lowland areas in Mekong region.

Acknowledgments Rice Gene Discovery Unit (RGDU) National Center for Genetic Engineering and Biotechnology (BIOTEC) Generation Challenge Programe (GCP)