Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 7657 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 rice varieties released from NSW DPI rice breeding program (Yanco) from 1987 to 2014. Two tolerant donor genotypes used in a number of populations were also included. Based on the solid phenotypic data that was gained from the phenotyping system, the researchers were able to use a genotyping-by-sequencing methodology to identify genetic regions of importance to cold tolerance. Subsequently, the quantitative trait loci (QTL) on chromosome 10 of the rice genome was confirmed and several genomic regions on chromosomes 5 and 7 were identified that contributed to an estimated reduction in spikelet sterility of 25% and 27%, respectively from genotypes in a cross using Lijiangheigu cold tolerant donor. Preliminary field trials at Yanco in 2014–15 season experienced a limited degree of cold induced sterility (33%) due to relatively warm (19.5°C) temperatures at early booting. However, spikelet sterility from 30 tiller cuts from 17 KKN genotypes and parents had a relatively strong positive relationship (r=0.56**, n=17) between field and glasshouse results, with Norin PL8, KKN9-216 and KKN11-221 having low sterility (Figure 1). Conclusion The project has resulted in the development of a successful phenotyping (screening) process that enables identification of cold tolerant genotypes, which will improve the efficiency of the rice breeding program in developing new varieties. The screening process will also enhance the ability of plant breeders to identify the regions of the rice genome that are important for cold tolerance, and therefore incorporate cold tolerance from breeding and international lines of rice into commercial rice varieties adapted to Australian conditions. RIRDC Project PRJ-007580 Cold tolerant traits and QTLs for improved efficiency of rice breeding program Further information Jaquie Mitchell T: 07 3365 1494 E: [email protected] Table 1: Cold tolerance at the early booting stage of rice varieties released by NSW DPI from 1987 to 2014. Cold tolerance was based on spikelet sterility determined at maturity. Variety Release year Grain type Spikelet sterility (%) Inga 1973 Long grain 31 Pelde 1982 Long grain 61 M7# 1983 Medium grain 18 Amaroo 1987 Medium grain 19 Bogan 1987 Medium grain 38 Doongara 1989 Long grain 39 Echuca 1989 Medium grain 14 Goolarah 1991 Fragrant long grain 11 Jarrah 1993 Medium grain 31 Kyeema 1994 Fragrant long grain 32** Langi 1994 Long grain 40* Millin 1995 Medium grain 26** Opus 1999 Short grain 24 Paragon 2003 Medium grain 55 Quest(CT18) 2003 Medium grain 28 Reiziq 2005 Medium grain 61** Sherpa 2011 Medium grain 19** Topaz 2014 Fragrant long grain 40* Cold tolerant donor genotypes used in crosses Norin_PL8 9** Lijianghiegu 18** #Released in Australia but bred in California (USA) * based on different experiment ** average performance across (3-5) booting stage stress experiments l Figure 1. Relationship between spikelet sterility (%) from 30 tiller cuts from field-grown rice in plots at Yanco and that from low temperature exposure at early booting in the UQ glasshouse screening of 15 KKN genotypes and parents. y = 0.443x + 8.46 R² = 0.32 Spikelet sterility (%) from early booting screening in glasshouse Spikelet sterility (%) from 30 tiller cuts (YST15 & YKKN15)