Quality Rice for North Asia

A report for the Rural Industries Research and Development Corporation by A.B. Blakeney, L.G. Lewin and R.F. Reinke

May 2001

RIRDC Publication No 01/42 RIRDC Project No BRE-1A

ISBN 0 642 58264 5 ISSN 1440-6845

Quality Rice for North Asia Publication No. 01/42 Project No. BRE-1A

The views expressed and the conclusions reached in this publication are those of the author and not necessarily those of persons consulted. RIRDC shall not be responsible in any way whatsoever to any person who relies in whole or in part on the contents of this report.

This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the Corporation is clearly acknowledged. For any other enquiries concerning reproduction, contact the Publications Manager on phone 02 6272 3186.

Researcher Contact Details

A.B. Blakeney L.G. Lewin Cereal Solutions CRC for Sustainable Rice Production PO Box 201 PMB YANCO NSW 2703 North Ryde NSW 1670

Phone: 02 9427 1449 Phone: 02 6951 2713 Fax: 02 9427 1449 Fax: 02 6951 2533 Email: [email protected]

RIRDC Contact Details Rural Industries Research and Development Corporation Level 1, AMA House 42 Macquarie Street BARTON ACT 2600

PO Box 4776 KINGSTON ACT 2604

Phone: 02 6272 4539 Fax: 02 6272 5877 Email: [email protected]. Website: http://www.rirdc.gov.au

Published in May 2001 Printed on environmentally friendly paper by Canprint

Foreword

North Asian markets have generally been unavailable to rice from Australia. However, in the longer term, these are potentially lucrative markets because: Australia can produce rice at low cost; we produce the soft cooking japonica rice so favoured in North Asian markets; and can provide fresh rice when it is not available in that region.

To thoroughly capitalise on this marketing opportunity, Australian producers must provide exceptionally high quality rice with characteristics that resemble the most favoured varieties in these markets.

This report summarises studies that aimed to define high quality for North Asian rice markets and a breeding program to produce new cultivars to satisfy these markets. The project culminated in the release of 'Opus' a new high yielding rice cultivar with grain quality approaching that of Koshihikari, the premium Japanese variety.

This project was funded from industry revenue which is matched by funds provided by the Federal Government. It was also partly funded by the McCaughey Memorial Trust, a body dedicated to support for irrigation research.

This report, a new addition to RIRDC’s diverse range of over 600 research publications, forms part of our Rice R&D program, which aims to improve the profitability and sustainability of the Australian rice industry through the organisation, funding and management of a research, development and extension program that is both market and stakeholder driven.

Most of our publications are available for viewing, downloading or purchasing online through our website:

• downloads at www.rirdc.gov.au/reports/Index.htm • purchases at www.rirdc.gov.au/eshop

Peter Core Managing Director Rural Industries Research and Development Corporation

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Acknowledgments

This project was jointly funded through an arrangement between the Rural Industries Research and Development Corporation, the McCaughey Memorial Trust and BRI Australia Ltd. The input of each of these organisations is gratefully acknowledged.

Many others, in addition to the Principal Investigators were involved in the multi-faceted work of this project. Mrs Anne Sheldrake was particularly important in the field component of the work at Yanco Agricultural Institute. Her untiring work is certainly greatly appreciated. There were many others, however, who contributed to the Yanco component. These included Melissa Fitzgerald with assistance from Colin Dunn, Alice Fiumara, Margrit Martin, John Smith, David Troldahl and Judy White.

We also acknowledge Dr Ken'ichi Ohtsubo and Yukihiro Hamada for their contributions to the program in many ways. The staff of Foss ® in Japan and Nireco (Japan) Corporation are acknowledged for their help with the taste analyser results.

The laboratory component of the project was conducted at BRI Australia. We thank Hayfa Salman for her assistance with this.

Contents

Foreword ...... iii Acknowledgments...... iv Executive Summary ...... vi 1. Introduction...... 1 1.1 Background ...... 1 1.2 Objectives...... 2 2. Methodology ...... 3 3. Detailed Results...... 6 3.1 New Introductions...... 6 3.2. Performance of Hitomebore...... 7 3.2.1 1998/99 Results ...... 7 3.2.2 1999/2000 Results ...... 9 3.3 Performance of Koshihikari Introductions...... 10 3.4 Crossing and Selection Program...... 11 3.5 Rapid Generation Advance ...... 11 3.6 Backcrossing Program ...... 12 3.7 Testing and Release of Opus (YRK4) ...... 12 3.8 RVA Analysis of Koshihikari and Opus...... 12 3.9 Taste Analysis of Japanese Style Rice ...... 13 3.9.1 Influence of protein content on Taste Value ...... 13 3.9.2 Degree of milling vs Taste Value ...... 15 3.10 Visiting Scientist Program...... 16 3.10.1 Dr Ken'ichi Ohtsubo...... 16 3.10.2 Mr Yukihiro Hamada ...... 16 4. Discussion of Results ...... 17 5. Implications...... 18 6. Recommendations...... 18 7. References ...... 18 8. Appendices ...... 19 Appendix 1: Application to Release ‘YRK4’ Rice...... 19

Executive Summary

The rice markets of Japan and Korea (North Asia) have always been of interest to Australian rice exporters because they prefer softer cooking 'japonica' rice. This is the type of rice most easily produced in NSW.

The markets were closed to Australian rice for more than 25 years. There was a short period when Korea imported rice due to a severe rice 'blast' epidemic. Japan imported rice in 1993 due to a disastrous cold event that seriously reduced yield.

By 1996, however, there were prospects that North Asian countries may become importers under the terms of the GATT. It was important, therefore, that Australian farmers be able to produce quality rice of a type that would be acceptable in North Asia.

The rice consumers in Korea and Japan had become increasingly quality conscious by 1996 as they became more affluent. One variety, Koshihikari, had become the dominant variety in Japan. This was due to its quality as it is a relatively low yielding, lodging susceptible variety. It was important that any variety for the Japanese market should match the quality of Koshihikari as closely as possible. The Korean market was not so dominated by one variety but consumers also preferred rice with qualities that matched those of Koshihikari.

The project studied the quality attributes of varieties required for Japan. It developed some techniques to select for improved varieties and increased the emphasis on a breeding program to select suitable varieties for the North Asian market.

Twenty six new introductions were made from Japan and forty nine from Korea during the life of the project. Some of the Japanese introductions were multiple ones of the same variety. There were five introductions of Koshihikari, for example, for it is alleged that there may be small variations in Koshihikari from different regions.

The variety Hitomebore was introduced from Japan in 1997. It was seen as the variety most likely to challenge Koshihikari for productivity and quality. Production characteristics of Hitomebore were disappointing in NSW. Its grain yield was significantly below that of Australian semi-dwarf varieties and probably not better than Koshihikari. Its physical grain quality was also disappointing as it was generally more chalky than Koshihikari and the best Australian varieties. It could not be recommended for commercial cultivation in NSW.

The local breeding program to improve varieties with Koshihikari type quality was enlarged as a result of this project. A total of 113 crosses were completed and 17 populations were advanced by single seed descent to reduce time required for variety development. A backcross breeding program to produce semi-dwarf Koshihikari was initiated. Preliminary results indicated, however, that this backcross program had not achieved significant improvement in yield, lodging susceptibility or grain quality.

The variety YRK4 was released to the rice industry as Opus in 1999. This semi-dwarf variety was developed from the 1987 cross between Koshihikari and Bogan, an Australian semi -dwarf, medium grain cultivar. Opus has yield potential approaching the high yielding semi-dwarf cultivars and quality attributes, such as grain shape and size, low chalk levels and soft cooking approached those of Koshihikari. Opus was planted on approximately 3% of the Year 2000 commercial rice crop and its yield was within the range of the higher yielding semi-dwarf cultivars.

A study of factors influencing the Taste Value of rice for the Japanese market indicated a negative correlation between protein content and acceptability. It also indicated that acceptability improved

with increased milling. These NIR methods for taste analysis also confirmed the relativity between Opus and Koshihikari for acceptability.

It was established that rice for the North Asian market should have low protein, low amylose content, be free from chalk and be well milled. These criteria, particularly chalk and protein content should be considered when selecting new varieties and in segregating rice for the premium North Asian market.

vii

1. Introduction

1.1 Background

At the commencement of this project, the major markets of Japan and Korea had been closed to Australia for about 25 years due to high tariffs and Government price fixing. Trade negotiations had seen small parcels of rice sold into these markets and there were indications that the trade restrictions would be progressively relaxed. The Australian rice industry was seen to be in an ideal position to service these markets as they were already producers of the high quality 'japonica' soft-cooking medium grain rice likely to be favoured and could provide freshly harvested rice when none was available in the marketplace. The Japanese market, in particular, preferred freshly harvested rice.

Rice quality perception in Japan had changed over the past 20 years as the population became more affluent. There was a distinct preference for premium rice and Japanese consumers were increasingly able to afford highest quality. Koshihikari had become the major variety in Japan. The area sown to other varieties was small when compared with the Koshihikari area (Figure 1). The predominance of Koshihikari was driven by market preference rather than production efficiency. While the Korean market remained less discriminatory, it seemed likely to become more so as affluence increased.

Figure 1: Area of major rice varieties in Japan (1985-1997)

600

500

Koshihikari Nipponbare Sasanishiki 400 Akitakomachi Kinuhikari Kirara 397 Hinohikari Hitomebore Haenuki 300 Mutsuhomare Area ('000Area ha)

200

100

0 1984 1986 1988 1990 1992 1994 1996 1998 Year

These markets can therefore be classed as high return but very quality conscious. Due to the potential for high returns, there was significant competition for the markets and this appeared likely to increase. Australia had been able to compete on quality terms but there was increasing awareness of the need to improve quality in the face of strong competition from USA, Thailand and China in addition to supplies from within Japan and Korea.

A previous RIRDC project (DAN 94A - Developing rices suitable for export to Japan) was completed in June, 1996. It was successful in defining the broad quality requirements, selection techniques and an initial germplasm base. It resulted in the release of one variety (Millin) and several improved breeding lines. These results were significant in establishing an Australian presence in Japan and indicating the long term commitment of the Australian industry to fulfil Japanese and Korean quality expectations. More work was needed, however to ensure that Australian rice was seen as of the highest quality.

The Australian industry had relied on the production of Koshihikari, the premium Japanese variety to satisfy the demand for premium quality rice for the Japanese export market. This would not be sufficient in the longer term, however. It was considered unlikely that Koshihikari could produce highest quality or acceptable yield when grown outside its narrow area of adaptation.

It was therefore considered necessary to refine quality definition, tests and selection procedures so that highest quality could be combined with acceptable productivity. Specific problems associated with the discriminating North Asia markets are:

• Appearance criteria are stricter than for other markets. • Textural specifications fall into a very narrow range. • In Japan, perception of quality is linked so closely to Koshihikari that understanding its quality attributes were an essential component of the project.

Taste has traditionally been measured in Japan by the use of expert tasters or expert taste panels. Rice is often traded in small quantities and is sold in the brown state by grower cooperatives, storage companies, or from Government stockpiles. Unlike any other region of the world, the cold storage of brown rice is common. Individual mills commonly employed a taste expert who evaluated all incoming rice and advised on its taste value. It is well known within Japan that the individual evaluation of lots by this subjective method gives quite variable results and that some tasters are much more discriminating than others. In 1988 the Satake Corporation, Japan's biggest suppliers of rice milling equipment patented an NIR apparatus for evaluating rice grain taste (US Patent 4,752,689). This technique has been refined since the first patent (see Methodology) and evaluation of the relationship between Taste Value and quality of rices for North Asia was seen to be important.

1.2 Objectives

1. To study and describe the quality criteria that discriminate between premium rices in North Asian markets and to develop quality evaluation procedures that will allow early generation selection of highest quality lines for use in these markets

2. To develop rice lines suitable for the Japanese market

3. To produce rice lines suitable for the Korean market.

2. Methodology

A multi-faceted approach was designed to define quality, introduce and evaluate existing cultivars and produce new cultivars. The planned methods were:

1. Establish quality criteria for the ideal Japanese rice. Some of these characters had already been defined (small grain, low amylose, soft texture on cooling, glossy appearance). More objective tests were required for some of the characteristics (eg. cooked rice texture) and additional criteria required in defining the ideal type. Specific tests for early generation selection were required to improve success in the breeding program.

2. Introduction of additional varieties. Much of the breeding work had concentrated on Koshihikari, the premium Japanese variety. Other Japanese varieties could contribute either as cultivars or parents. An enlarged introduction and testing program was planned to highlight the strengths and weaknesses of a broader range of Japanese and Korean varieties.

3. Quality evaluation of all Japanese lines already in the breeding program. Characters to be evaluated included grain size, amylose and texture attributes.

4. Development of semi-dwarf Koshihikari. The yield of Koshihikari in NSW is limited by its tall stature and lodging susceptibility. A backcrossing program to reduce the height was planned. While a semi-dwarf Koshihikari may not become a commercial cultivar, it would be useful as a parent in the improvement program. The strategy for backcross breeding is illustrated in Figure 2.

5. Creation of a more extensive and efficient breeding program to breed varieties with Japanese quality. This was to involve rapid generation techniques such as anther culture and/or single seed descent to provide improved varieties within 8 years. A scheme for the Yanco improvement program is outlined in Figure 3.

6. Methodology validated through provision of two visiting fellowships to bring Japanese perspective to the project and to provide important contacts for the future.

7. The Rapid Visco Analyser (RVA) is used in the Yanco rice improvement program as a major quality selection tool (Blakeney, 1996). RVA analysis is also now widely used in most rice breeding programs to characterise cooked grain texture. It was important that the technique be used to characterise quality in significant new selections.

8. Taste evaluation. The original Satake Taste Value patent was taken out in 1988 (US Patent 4,752,689). This apparatus was, in fact a filter NIR instrument calibrated to measure amylose, protein, moisture and free fatty acids and to combine the results of these analyses into a single taste value using the formula:

Taste Value = K * (amylose content)a * (protein content)b * (15 + (15-moisture content))c

Later, a factor for free fatty acids was incorporated. Other NIR manufacturers were quick to develop alternatives. These formula based instruments were later replaced by scanning NIR instruments that correlated average Taste Values determined by taste panels with white rice spectra using PLS or other advanced chemometric algorithms. These latter instruments have better standard errors of prediction (typically quoted as 2-3 taste units) and NIRECO (NIRsystems 6500) instruments have been used throughout this study. The manufacturers of taste analysers in Japan are in general unwilling to sell their taste calibrations and also not keen to sell calibrated instruments outside Japan. This is principally due to the difficulty of maintaining calibrations at

distant locations but probably also reflects some Japanese reservations on how instruments, and the results they generated, would be used by non-Japanese researchers. After negotiations with several Japanese suppliers and calculating the costs involved, we decided that it would be better to have our analyses done in Japan. We have, however, used blind duplicates and more than one collaborator to ensure that consistent Taste Values are obtained. This approach has proven useful and cost effective. In the past few years, American researchers at the USDA Southern Regional Research Laboratory have obtained a modern version of the Satake instrument, but have had difficulty interpreting the NIR component results on US rices They have, however used the Taste Values to evaluate existing US rice varieties.

Figure 2: Scheme for backcrossing program for semi-dwarf Koshihikari (5 crosses to Koshihikari).

Semi dwarf parent x Koshihikari sd1 sd1 Sd1 Sd1

50% Koshihikari (Sd1 sd1) X Koshihikari (Sd1 Sd1)

1 75% Koshihikari (50% Sd1 sd1, 50% Sd1 Sd1) x Koshihikari (Sd1 Sd1)

2 87.5% Koshihikari (50% Sd1 sd1, 50% Sd1 Sd1) x Koshihikari (Sd1 Sd1)

3 93.75% Koshihikari (50% Sd1 sd1, 50% Sd1 Sd1) x Koshihikari (Sd1 Sd1)

96.875% Koshihikari (50% Sd1 sd1, 50% Sd1 Sd1)

Self-pollinate progeny

Select semi-dwarf (25%sd1sd1) 96.875% Koshihikari but semi-dwarf

Notes 1: Must make at least 8 separate crosses to ensure one parent plant is Sd1sd1 (99.5% probability) 2: Must progeny test each cross to determine if line is carrying semi-dwarf gene. For each cross sow at least 16 plants to ensure classification with 99% probability. 3: Need to repeat the progeny testing process. NB Plants with the genotype Sd1 Sd1 are tall; Sd1 sd1 are tall; sd1 sd1 are semi dwarf. It is possible to achieve 2.5 generations per year in the glasshouse.

Figure 3. Schematic diagram of improvement program. Arrows indicate seed flow.

Standard Program Alternate Program

Cross

Backcrossing

F1 Single Seed Descent or Anther Culture

F2 Populations

F3 and F4 Panicle Rows

Unreplicated Plots Advanced Panicle (10,000 rows) Rows

Replicated Plots Seed Increase

District Trials and Seed Increase

Release

3. Detailed Results 3.1 New Introductions

New varieties introduced from Japan and Korea over the life of the project are included in Table 1. Many of these introductions were made with the help of visiting fellows Dr Ohtsubo and Mr Hamada. The varieties varied significantly in grain quality and the best of these lines have been used in the crossing program (Table 2)

Table 1a. Varieties introduced from Japan 1997 to 1999

Variety Year Comments Variety Year Comments Haenukai 1997 Akitakomachi 2 1999 High quality Hinohikari 1997 Aoinakaze 1999 Hitomebore 1997 High quality Hananomai 1999 Kirara 397 1997 Hokkaido Hatsushimo 1999 Koshihikari (T) 1997 Jugayamochi 1999 Waxy Koshihikari 1 1997 Kijumochi 1999 Waxy Koshihikari 2 1997 Matsuribari 1999 Koshihikari 3 1997 Megumimochi 1999 Waxy Miyamanishiki 1997 Sake variety Nippon Bare 2 1999 Omachi 1997 Sake variety Todorokiwase 1999 Aichi 93 1999 Wakamizu 1999 Aichinokoari 1999 Yamadanishiki 1999 Akanezora 1999 Koshihikari (H) 1999

Table 1b. Varieties introduced from Korea, 1997 to 1999

Variety Year Comments Variety Year Comments Cheolweon 1997 Tongil (2) 1997 Low quality Cheolweon (Baegambyeo) 1997 High quality Unbong 1997 HR 3990-1-1-5 1997 Cheolweon 35 (Daeseungbyeo) 1998 HR 4856-1-1-1-1-2 1997 IRI 348 (Dongjinbyeo) 1998 High quality HR 5824-B-3-2-3 1997 IRI 353 (Seomjinbyeo) 1998 High quality HR 6419-B-42-2 1997 IRI 372 (Hwacheonghyeo) 1998 High quality HR 7896-ACB7 1997 IRI 386 1998 IRI 384 1997 Milyang 15 (Nagdongbyeo) 1998 High quality Jinbu 8 1997 Minehikari (Bonggwangbyo) 1998 High quality Jinbu 9 1997 SR 3049 58-1-5-1 1998 Milyang 54 1997 SR 10255-58-1-5-1 (2) 1998 Milyang 77 1997 SR 10619-15-2-B-B-2-3 1998 Milyang 93 1997 High quality SR 10649-B-285-2-2 1998 (Sangnambatbyeo) SR 11451-T204 1997 SR 10843-32-1-4-2 1998 SR 11842-91-4-3 1997 SR 11133-23-2-4-2-1-2 1998 Suweon 222 1997 SR 11327-22-3-2 1998 Suweon 325 1997 SR 13363-28-2-1 1998 Suweon 325 1997 SR 13618-9-3-2 (2) 1998 Suweon 332 1997 SR 13925-13-1 1998 Suweon 333 1997 Suweon 235 (Sanpungbyeo) 1998 High quality Suweon 345 1997 Suweon 330 (Hwaseongbyeo) 1998 High quality Yeongdeog 5 1997 Unbong 1 (Unbongbyeo) 1998 High quality YR 3825-B-B-23 1997 Gihobyeo-M2-6-1 1999 YR 6488-ACP36 1997 HR 6852-78-4-2-3 1999 YR 6488-ACP39 1997

In addition to new varieties, several new introductions of Koshihikari were made to attempt to improve the quality of Australian grown Koshihikari. It has long been recognised that Koshihikari as eaten in Japan does vary from region to region. Koshihikari from Niigata prefecture, for example, is recognised as having the best quality. Some of this variation is undoubtedly due to environment but we became aware of potential genotypic variation soon after the commencement of the project. Five

new introductions were made to sample this potential variation. Seed increase of these was carried out during the life of the project to allow a comparison on the basis of quality and field characteristics. This will be carried out during the 2000/2001 season.

Hitomebore was another significant introduction from Japan. It is essentially semi-dwarf Koshihikari and carries with it the quality advantages of Koshihikari. It is more resistant to lodging than Koshihikari but not as resistant as expected from its semi-dwarf stature.

More than 40 varieties were introduced from Korea over the life of the project. These were essentially the best of the Korean varieties but these were of lower quality than the best of the Japanese varieties.

Table 2. Varieties from Japan and Korea used in crosses 1996 to 1998 (Numbers in the body of the table indicate the number of crosses involving that parent.

Variety 1996 1997 1998 YRK4 (Opus) 5 9 7 Koshihikari T 8 5 Koshihikari 1 4 4 Koshihikari 2 7 2 Koshihikari 3 8 3 Ishikari 1 Haenukai 4 5 Hitomebore 18 7 Kirara 397 4 2 Hinohikari 5 SR11327 2 HR6852 2 IR60590 1

3.2. Performance of Hitomebore.

Hitomebore is a semi-dwarf Koshihikari line introduced from Japan. It was considered to be sufficiently promising to warrant significant seed increase in the 1997/98 season to allow district evaluation in the 1998/99 season. Preliminary testing was sacrificed in the 1997/98 season to allow maximum seed increase.

3.2.1 1998/99 Results

Nine trials were sown throughout the ricegrowing area in 1998/99 to test Hitomebore along with the most promising lines and commercial cultivars of similar maturity. A trial was also sown at Leeton Field Station to test physical quality attributes of the variety against common commercial cultivars.

Hitomebore is early maturing. It was generally earlier to flower than Millin and Opus (Table 3). Koshihikari maturity is similar to that of Opus and so would be of slightly longer duration than Hitomebore. Table 3. Average days to flowering of advanced lines taken from a series of northern and southern trials

Variety Grain Type a Pedigree North South Millin M Standard 92 104 Illabong B Standard 92 102 YRM42 M M201/Bogan 93 103 YRM49 M Amaroo/M201 89 104 YRM61 M M7*2/Somewake//YRM4 92 102

YRL118 L YRL30///YR73/Banat 725//Inga110 104 Langi L Standard 113 107

Opus (YRK4) K Bogan/Koshihikari 96 108 Hitomebore K Standard 89 105 a Grain type, Medium grains (M), Koshihikari types (K), Long grains (L) and Arborio types (B). Hitomebore- new entry with Koshihikari quality grains, short-strawed and cold tolerant.

Grain yield of Hitomebore averaged only 89% Millin and 82% Opus over all trials (Table 4). It was equivalent to Opus yield on two sites but these were both sites where straighthead (a physiological disorder) is a potential problem. Straighthead is a minor problem and Opus and Koshihikari are known to be very susceptible.

Table 4. Yield of advanced lines at each of six sites and the mean across all sites.

Yield (t/ha @ 14% moisture): Yield (t/ha @ 14% moisture): Variety Northern sites Southern sites Griffith Colly. Leeton Barham Deni Finley Mean Illabong 12.3 10.7 9.5 5.3 13.4 13.0 10.7 Millin 11.9 9.6 8.3 5.2 11.4 11.1 9.6 YRM42 9.7 9.5 8.3 6.6 12.9 10.8 9.6 YRM49 10.0 9.8 8.7 9.1 13.7 12.2 10.6 YRM61 10.7 9.4 8.0 5.8 12.5 10.4 9.5

YRL118 13.0 10.6 8.5 11.7 13.6 10.6 11.4 Langi 10.5 10.0 8.0 8.5 13.4 12.2 10.4

Opus 12.1 11.0 9.0 5.3 13.2 11.5 10.4 RCLH 7.9 8.8 7.4 7.2 7.7 11.9 8.5 lsd (p<0.05) 1.7** 0.5** 1.2** 3.0** 1.4** 0.8** 1.0**

Physical attributes of Hitomebore quality were as expected for a high quality Japanese variety (Table 5). It is classified as a short grain and is relatively free from chalk. Milling quality of all varieties in this trial was excellent. Small differences could be attributed to maturity and environmental differences at the time of harvest. The milled grain colour of Hitomebore was poor and this is a characteristic that would need to be further evaluated if the variety were to be grown commercially. There was also a trend for Hitomebore chalk levels to be higher than those for YRK4 (Opus).

Table 5. Grain quality results from the Leeton Field Station trial. Results are the mean of three sample dates. Characters recorded are: Hd (days sowing to anthesis), %wg (%whole grain after milling); %chalk (total chalky area as a percentage of total grain area as measured by image analysis); Yel (yellowness index - a lower value is whiter); length (mm) and width (mm) of brown rice kernels.

Variety Hd %wg %chalk Yel Length Width Amaroo 125 73.0 2.2 35.3 5.8 2.7 Namaga 124 71.6 2.0 36.8 5.5 2.7 Millin 112 66.3 0.9 35.1 5.7 2.8 Koshihikari 115 66.0 1.8 34.1 5.6 2.8 YRK4 116 67.9 0.4 36.3 5.3 2.8 Hitomebore 110 66.2 0.8 38.6 5.0 2.8 Koshihikari 1 115 69.4 0.8 38.6 5.0 2.8 Koshihikari 2 114 67.2 0.7 36.7 5.1 2.9 Koshihikari 3 115 63.1 0.3 38.5 5.0 2.8 lsd(p<0.05) 3 4.0 0.8 1.4 0.1 0.1

3.2.2 1999/2000 Results

Four trials were sown in 1999/2000 to further test Hitomebore performance. These trials included Opus and other commercial medium grain cultivars. They did not include Koshihikari as this would require multiple nitrogen rates. The performance of Hitomebore was again disappointing (Table 6) and probably no better than Koshihikari in similar situations. It was more susceptible to lodging but, even in the absence of lodging did not yield at levels that would make it acceptable to Australian farmers. Table 6. Yield of advanced lines at each of four sites and the mean across all sites.

Yield (t/ha @ 14% moisture) Variety Leeton Griffith Colly. Barham Mean Namaga 9.1 10.9 9.6 12.6 10.5 Millin 9.0 10.9 9.8 11.9 10.0 Opus 8.4 10.5 9.6 11.3 10.0 Hitomebore 5.8 7.2 5.2 9.1 6.8

LSD0.05 1.2** 0.6** 1.2** 1.0** 0.6**

Grain quality was again assessed in a trial at Leeton Field Station where multiple harvests were taken through the maturation period (Table 7). Hitomebore quality did not match that of new Koshihikari introductions nor was it superior to Opus, particularly for chalk.

Table 7. Grain quality results from the Leeton Field Station trial. Results are the mean of four sample dates. Characters recorded are: Hd (days sowing to anthesis), %wg (%whole grain after milling); %chalk (total chalky area as a percentage of total grain area as measured by image analysis); Yel (yellowness index - a lower value is whiter); length (mm) and width (mm) of brown rice kernels.

Variety Hd %wg %chalk Yel Length Width Amaroo 127 71.8 3.1 32.8 5.8 2.8 Namaga 125 72.9 3.2 34.1 5.7 2.7 Millin 115 65.3 5.8 35.8 5.6 2.8 Koshihikari 119 70.9 2.1 35.1 5.1 2.8 Opus 117 73.8 1.7 36.5 5.0 2.9 Hitomebore 111 72.4 3.1 36.4 5.3 2.9 Koshihikari 1 117 73.8 0.8 35.0 5.0 2.9 Koshihikari 2 117 71.1 1.0 38.0 5.1 2.9 lsd(p<0.05) 3 3.8 1.2 1.5 0.1 0.1

It was again apparent that the Australian sourced Koshihikari seed was inferior to new introductions of Koshihikari. This was particularly true for chalkiness. This would suggest that there has been some shift in Koshihikari genotype in Australia and it should be tested against the new introductions.

3.3 Performance of Koshihikari Introductions

Three new introductions of Koshihikari (designated Koshihikari 1,2 and 3) were made in 1997. These were increased from single rows in the 1997/98 season and sown as single plots for seed increase in 1998/99. Yield was not measured on these plots but there were measures of physical quality attributes. The introductions were sown in one replicated field trial at Leeton Field Station and in a quality evaluation trial at the same location in 1999/2000.

The 1998/99 results suggested that the new introductions varied significantly from Australian grown Koshihikari (Table 5). This variation was particularly for grain size and chalkiness.

Grain yield results in 1999/2000 suggested that there was little variation for grain yield between Australian grown Koshihikari and the new introductions but that there was variation for chalkiness (Table 8). These grain quality results were confirmed in the serial harvests for grain quality (Table 7).

There is a need to review the seed used for Australian grown Koshihikari and it is recommended that the new introductions be further increased with testing to continue. The best line should then be increased for commercial production.

Table 8. Results from the Leeton Field Station Koshihikari replicated trial. Results are the mean of three replicates. Characters recorded are: Hd (days sowing to anthesis), %wg (%whole grain after milling); %chalk (total chalky area as a percentage of total grain area as measured by image analysis); Yel (yellowness index - a lower value is whiter); length (mm) and width (mm) of brown rice kernels.

Variety Yield Hd %wg %chalk Yel Length Width Amaroo 13.9 124 71.5 4.1 33.9 5.9 2.9 Namaga 12.7 122 71.5 4.1 32.5 5.8 2.9 Millin 12.8 112 58.6 6.1 32.7 5.7 3.0 Opus 11.8 122 74.0 2.3 35.7 5.1 3.0 Koshihikari 6.9 124 72.4 1.3 36.0 5.1 2.9 Koshihikari 1 6.4 125 74.8 0.3 35.9 5.1 2.9 Koshihikari 2 7.4 126 71.1 0.8 35.8 5.1 2.9 Koshihikari 3 7.0 124 73.5 0.5 37.2 5.1 2.9 lsd(p<.05) 1.4 2 3.0 2.2 0.6 0.1 0.1

3.4 Crossing and Selection Program

A total of 113 crosses were made during this project. The progeny of these have been fed into the breeding program that has been developed to specifically develop varieties for North Asia.

3.5 Rapid Generation Advance

Australian varieties were evaluated for their potential for anther culture. While regeneration rates averaged around 5%, this was not sufficient to allow efficient use of the technique for the program. Single seed descent was therefore used to rapidly generate advanced lines. Seventeen populations were advanced through this program in the course of the project. Crosses used in creating these populations are detailed in Table 9.

Table 9. SSD program for the Quality Rice for North Asia Project

Cross Parents YR92172 Koshihikari/YRM34 YR92173 YRM39/YRK2 YR93005 YRM41//Koshihikari/M401 YR93013 M7*2/Somewake//Koshihikari/3/M102 YR94150 YRM41/YRK2 YR94161 M103/YRK2 YR94162 Jarrah/YRK2 YR94167 M401/YRK2 YR94178 YRK2/M401 YR94205 YRM42/Akihikari YR95006 Koshihikari/Pelde YR95147 Pelde/Koshihikari YR96017 YRK4/ Koshihikari(T) YR96018 Koshihikari(T)/YRK4 YR96040 Koshihikari(T)/M202 YR96138 Koshihikari(T)/Kyeema YR96158 Millin/ Koshihikari(T)

3.6 Backcrossing Program

A backcrossing program was initiated to produce semi-dwarf Koshihikari. While this objective was successfully achieved, the lines produced were lodging susceptible and quality was generally inferior to that of Opus. This was confirmed in a trial at Leeton field station in 1998/99 season (Table 10).

Table 10. Performance of 5 lines at Leeton (1999). DwK-1 and DwK-2 are two semi-dwarf Koshihikari lines. Hd is days sowing to anthesis; Grain yield is tonnes per hectare at 14% moisture; Length and Width are for brown rice (mm); % chalk is % chalky area as measured by image analysis.

Line Hd Grain yield Length Width %chalk Opus 110 12.5 5.3 2.8 0.5 Koshihikari 110 8.1 5.5 2.8 1.5 Hitomebore 107 8.2 5.4 2.8 1.3 DwK-1 110 8.9 5.5 2.8 1.5 DwK-2 110 8.9 5.6 2.8 1.5 lsd(p<.05) 2** 1.5** 0.1** 0.1 n.s. 0.8**

3.7 Testing and Release of Opus (YRK4)

YRK4 is a line developed from the 1987 cross between Bogan, a NSW commercial cultivar and Koshihikari. It was selected from a program designed to create lines with high yield potential but with the quality characteristics to enable them to compete with Koshihikari on the North Asian market.

By the commencement of this project there were a series of lines with potential but they had not been discriminated on the basis of yield or quality. The most promising of the lines were all derived from the cross YR87332. YRK4 was identified as the line with greatest potential, based on grain size and shape and also on NIR taste analysis equipment in Japan.

YRK4 was tested as a component of this project. It was released to the rice industry as Opus in March 1999. The full description of testing is included in Appendix 1: 'Application to release YRK4 rice'.

In summary, Opus (YRK4) has advantages of increased yield over Koshihikari when grown in NSW. As a semi-dwarf variety this is partly attributed to improved lodging resistance and partly due to improved nitrogen response. The average advantage of Opus over Koshihikari was 17% in district testing. Opus did not yield as well as other semi dwarf commercial cultivars. Its average disadvantage ranged from 2 to 5%. Opus has quality attributes that make it suited to North Asian cuisine. It has smaller grain than commercial medium grain cultivars, lower amylose content and softer texture. A significant feature of Opus quality performance was freedom from chalk.

3.8 RVA Analysis of Koshihikari and Opus

In this project it was important to obtain crossbred lines with textural properties as close to Koshihikari, the best Japanese premium rice as possible. RVA analysis was used at all stages of early generation selection to select crosses with potential and to eliminate less promising lines.

When samples from the same site at similar yield levels are grown together, the RVA pattern reflects inherent starch properties that influence texture. When samples from several locations and soil fertility are assessed, however, the RVA pattern of texture is known to be influenced by protein content, mineral content and the level of fertiliser breakdown and oxidation.

When YRK4 was selected as promising, it was additionally necessary to establish that its texture was of the same order as Koshihikari throughout the environmental range in which it would be grown. Samples of both rices were grown in nitrogen rate district trials at sites throughout the MIA, CIA and Murray Valley. Figure 4(a and b) illustrates the RVA's obtained. It should be noted that the curves for YRK4 (Opus) and Koshihikari indicate that both varieties will have similar textures when grown under a full range of environmental conditions.

Figure 4. RVA curves of Opus and Koshihikari from District variety * nitrogen rate trials.

Koshihikari - Dark lines YRK4 - Light lines

Koshihikari - Dark lines YRK4 - Light lines Second Set

3.9 Taste Analysis of Japanese Style Rice

3.9.1 Influence of protein content on Taste Value

Two varieties (Koshihikari and Opus) were analysed for the relationship between protein content and taste analysis result. Samples were extracted from a variety x nitrogen rate trial to represent a range in protein content. These samples were analysed for both protein (Leico nitrogen) and taste analysis (Nireco Corporation). All samples were undermilled with yellowness index of 33 to 35.

Taste value is clearly related to protein content in Japanese style rices (Table 11 and Figure 5). Lower protein rice has higher value and is more acceptable. This is very important in marketing softer cooking rices to Japan.

Table 11. Protein content (%) vs Taste Value (Nireco Corporation, Japan). Samples were undermilled and are the mean of three analyses for each character. A higher Taste Value indicates a higher preference rating for Japanese quality.

Opus Koshihikari Protein (%) Taste Value Protein (%) Taste Value 9.10 58 8.94 60 8.42 61 8.46 63 8.11 64 8.21 65 7.65 68 7.68 70 7.22 73 7.14 76 6.81 79 6.76 82 6.24 86 6.31 87 5.82 88 5.92 89

Figure 5. Taste Value vs Protein Content in Koshihikari and Opus. For Opus TV=146.7 - 10.04 * protein. For Koshihikari Taste Value = 150.89 - 10.35 * protein.

100

Opus (r2=0.98) 90 Koshihikari (r2=0.99)

70 Taste Value Taste

50 5678910 Protein Content (%)

3.9.2 Degree of milling vs Taste Value

One method of determining degree of milling is by measuring the yellowness index of the milled sample. Samples of Opus and Koshihikari were milled to varying degree and those with different degree of milling were subjected to taste analysis. Clearly, degree of milling was important in determining the acceptability of the milled rice (Table 12 and Figure 6). More highly milled rice had higher taste value and was therefore more acceptable. The relationship is not linear but, despite this, the linear regression for each variety explains 94% of the variation in taste value.

Non linearity is probably associated with the change in milling degree. The NIR taste analyser is calibrated at Japanese levels of milling and, as milling level is increased, the defined relationship between NIR and subjective taste assessment may vary.

Table 12. Yellowness Index vs Taste Value (Nireco Corporation, Japan). The mean of three analyses for each character.

Opus Koshihikari Yellowness index Taste Value Yellowness Index Taste Value 38.4 68.3 39.2 74.2 36.2 74.4 37.4 76.1 35.3 76.5 36.3 77.3 34.7 77.2 35.2 78.2 34.2 78.4 34.8 79.4 33.8 80.3 33.6 80.7 33.2 82.4 33.1 82.9 32.6 86.3 32.4 84.3 32.4 86.2 32.1 86.1 31.8 87.3 31.7 88.7 30.9 88.2 31.0 88.9 30.2 88.6 30.5 89.2 29.4 89.4 29.9 89.9

Figure 6. Taste Value vs Yellowness Index for Koshihikari and Opus

Taste Value Taste 75 Opus Koshihikari 70

65 28 30 32 34 36 38 40 Yellowness Index

3.10 Visiting Scientist Program

3.10.1 Dr Ken'ichi Ohtsubo

Dr Ohtsubo was invited to visit Australia to interact with the rice quality testing program. His particular interest was in the measurement of rice quality and particularly NIR taste analysis. Work conducted with his cooperation is reported under the taste analysis report.

Dr Ohtsubo also attended the Pacific Rim Symposium conducted in conjunction with the 48th Australian Cereal Chemistry Conference in 1998. His report to that conference is reproduced in Appendix 2.

3.10.2 Mr Yukihiro Hamada

Mr Hamada visited Yanco Agricultural Institute from Aichi Agricultural Research Institute in Japan. His primary purpose was to study the growth and yield of Koshihikari and Australian cultivars in response to different fertiliser and sowing treatments. While the main purpose for his visit was outside the range of this project, we were able to capitalise on the relationship to introduce many cultivars that would otherwise have been unavailable. We also used his expertise to develop an understanding of the taste differences between Australian and Japanese rice varieties.

Plate 1. (l. to r.) Dr Lewin, Mr Hamada and Dr Batten during one of Mr Hamada's many tasting sessions

4. Discussion of Results

The range of new introductions from both Japan and Korea has enabled access to the latest rice genetic background from both countries. This was essential for improving quality characteristics in the development of specific varieties for these important markets. The range of material will also be important for other characteristics. Hitomebore and Haenuki, for example, are good sources of cold tolerance and Kirara 397 is of very short duration when grown in the NSW rice area.

It had been expected that Hitomebore was a potential commercial cultivar for NSW. When introduced, it had the reputation in Japan as a cultivar with good quality and better agronomic characteristics than Koshihikari. This was not verified for NSW conditions. Agronomic performance of Hitomebore was disappointing and probably no better than that of Koshihikari. Grain quality was also disappointing with inferior milled grain colour and a tendency to higher chalk levels. It is not a suitable candidate for commercial cultivation in NSW.

New introductions of Koshihikari had different characteristics to those of Australian grown Koshihikari. This was particularly true for grain size and chalk levels. It is clear, therefore, that field and quality comparisons between all Koshihikari introductions will be required to select the most appropriate line for future increase.

Backcrossing successfully produced semi-dwarf Koshihikari. Australian grown Koshihikari was used as the recurrent parent, however. This may explain the disappointing yield and quality characteristics of the semi-dwarf line. A new program should be instigated to develop a more appropriate semi-dwarf Koshihikari for future use in the crossing program. This program can now be more easily accomplished since there has been a genetic marker developed for the semi-dwarf gene.

The enlarged crossing, selection and testing program developed with the assistance of this project will provide the platform for the future development of lines specifically for the North Asian market. This will also be assisted by the selection techniques that were developed under the project.

This program successfully demonstrated the worth of YRK4, which was released to the rice industry as Opus in March 1999. Opus had a 17% yield advantage over Australian grown Koshihikari and this was combined with excellent physical quality attributes and good cooking quality.

Taste analysis using the NIR Taste Analysers in Japan was a very useful and robust technique for determining quality for the North Asian market. It was also useful for illustrating the importance of various quality criteria such as protein content and degree of milling in manipulating the quality estimates and so acceptability in Japan. Use of this technique also highlighted the acceptability of Opus using Japanese measures of quality.

5. Implications Major findings from this project have been included in the NSW Agriculture rice improvement program. These have included:

• The introduced lines have been included in the crossing program; • Populations from the relevant crosses have been included in the selection program; • Selection methods have been modified through a better understanding of the quality requirements for North Asian markets; • Contacts that were made during the project have been lasting ones and will facilitate the flow of information from Japan. We have already used contacts with Mr Hamada to assist with arranging visits to Japan and with equipment supplies.

The understanding of Taste Value from this project has allowed better targeting of the Japanese market and improvement in our credibility as a supplier to that market.

The release of Opus is an important milestone in the development of varieties specifically for North Asian markets. This is exemplified by the uptake of Opus since its release. Opus occupied 0.6% of the NSW rice area in 1999 and 2.8% in 2000. Koshihikari was produced on 6.3% in 1999 but only 3.2% in 2000. Growers were offered a premium of 60% to grow Koshihikari but only 15% for Opus in the 2000 rice crop.

6. Recommendations 1. Opus should be promoted as a variety suited to the Japanese and Korean market. 2. Segregation for the Japanese market, in particular, would improve acceptability. Key characters are: • suitable varieties; • low protein; • maintaining maximum moisture consistent with quality. Moisture should not fall below 14%; • greater degree of milling will increase Taste Value but care must be taken to ensure that grains do not get too hot during the milling process and cracking during milling is avoided. 3. A specific program to breed varieties for North Asia should be maintained. 4. Selection on the basis of Taste Value should be maintained for varieties for North Asia. 5. A backcrossing program to produce semi-dwarf Koshihikari with new introductions as the recurrent parent should be initiated.

7. References

Blakeney, A.B. (1996). Rice. In: Henry, R.J and Kettlewell, P.S. eds. Cereal Grain Quality. Chapman Hall, London. pp 53-76.

Ohtsubo, Ken'ichi, 1998. Rice based convenience foods. In: Blakeney, A.B. and O'Brien, L. Editors. Pacific People and Their Food. American Association of Cereal Chemists, St. Paul. pp25-36.

8. Appendices

Appendix 1: Application to Release ‘YRK4’ Rice

‘YRK4’ is a semi-dwarf rice line with grain dimension and cooking quality attributes that will suit it to Japanese style cuisine. It has higher yie ld potential in the NSW rice area than ‘Koshihikari’, the premium Japanese variety and its grain characteristics are more suited to Japanese cuisine than ‘Millin’ or other Australian medium grain cultivars.

Origin

‘YRK4’ was developed from the 1987 cross YR 87332 (‘Bogan’/’Koshihikari’). ‘Bogan’ is a medium grain cultivar that was grown commercially in NSW from 1987 to 1997. ‘Koshihikari’ is a Japanese cultivar renowned for its soft cooking characteristics and is the most favoured cultivar in the Japanese market. ‘Koshihikari’ is also the dominant cultivar in Japan with over 30% of the Japanese rice area. An F2 population from YR87332 was selected in 1990. Single panicle rows were sown in 1991 and 1992. One row was harvested in 1992 and progeny sown in unreplicated trials in 1993 and 1994. At this stage, the line was identified as having potential for Japanese cuisine and replicated plots were sown in 1995 and 1996. The line was re-selected for seed increase in 1994. District trials were sown in 1996/97 and 1997/98. The line YR87332.27.7 was renamed ‘YRK4’ for the district testing and seed increase phase.

Agronomic Characteristics

‘YRK4’ is a semi-dwarf variety and is always shorter than ‘Koshihikari’. Plant height is similar to ‘Millin’, ‘Amaroo’ and ‘Namaga’.

‘YRK4’ is a pubescent variety. It has hairs on the grain and leaves. In this respect, it resembles ‘Koshihikari’ but contrasts with ‘Millin’, ‘Amaroo’ and ‘Namaga’ that are all glabrous.

‘YRK4’ has tip awns. Awns are evident on the tips of terminal spikelets, although the degree of awnedness is affected by environmental conditions. ‘Koshihikari’ tends to be less awned.

‘YRK4’ is intermediate for duration. It is earlier to flower than ‘Amaroo’ and ‘Namaga’ but later than ‘Millin’. Duration is similar to ‘Koshihikari’.

Grain shape and size is similar, or slightly smaller than ‘Koshihikari’ and certainly smaller than the medium grain cultivars ‘Millin’, ‘Amaroo’ or ‘Namaga’. This is a desirable characteristic for Japanese appearance quality.

Table 1: Average values for agronomic characteristics for ‘YRK4’ and for other relevant cultivars. Data is averaged over four trials in 1997 and 1998. Hd is days from sowing to anthesis; Ht is plant height in cm from ground to tip of extended panicle; length and width is of brown rice (mm).

Cultivar Hd Ht Length Width YRK4 119 88 5.3 2.9 Millin 114 84 5.6 2.9 Amaroo 126 95 5.9 2.9 Namaga 124 93 5.7 2.8 Koshihikari 121 100 5.5 2.9

Grain Yield

‘YRK4’ has been compared with the commercial medium grain cultivars in research station trials since 1995. ‘Koshihikari’ was included in the 1997 and 1998 trials. ‘YRK4’ was also compared with these varieties in district trials in 1998.

Table 2: Grain yield (te/ha at 14% moisture) in research station trials at Yanco and Deniliquin (Deni) from 1995 to 1998

Cultivar 1995 1996 1997 1998 Mean Yanco Deni Yanco Deni Yanco Deni Yanco Deni Yanco Deni YRK4 9.7 13.4 8.9 8.3 10.3 10.0 10.3 12.4 9.8 11.0 Millin 10.0 12.5 10.4 10.3 10.3 10.2 10.4 12.2 10.3 11.3 Amaroo 10.3 12.5 8.7 6.5 10.6 10.6 10.1 11.6 9.9 10.3 Namaga 10.4 12.3 10.9 8.0 10.9 10.6 11.8 11.8 11.0 10.7 Koshihikari 8.8 9.8 9.9 lsd (p<0.05) 1.2 1.2 0.9 1.4 1.5 1.1 2.0 1.0 0.8 1.0

Table 3: Grain Yield (te/ha at 14% moisture) in district trials 1997/98. Sites were at Leeton, Coleambally (Colly), Finley, Deniliquin (Deni) and Barham.

Variety Leeton Colly Finley Deni Barham Mean YRK4 9.9 12.8 11.6 10.4 5.7 10.1 Millin 10.2 12.2 12.5 10.3 8.5 10.7 Amaroo 11.2 12.4 12.2 9.7 8.1 10.7 Namaga 11.4 12.1 12.0 10.7 8.2 10.9 Koshihikari 9.0 8.7 10.5 8.0 4.5 8.1 lsd (p<0.05) 1.2 0.8 1.0 1.1 2.2 1.0

Grain yield of ‘YRK4’ exceeded that of ‘Koshihikari’ in all eight direct comparisons and was significantly greater in four of these. Average yield of ‘YRK4’ in these comparisons was 10.1 te/ha compared with 8.7 te/ha for ‘Koshihikari’, a 17% yield advantage overall. This advantage was partly due to reduced susceptibility to lodging but also a result of better response to applied nitrogen due to its shorter stature.

‘YRK4’ was lower yielding than the medium grain varieties. It was lower yielding than ‘Millin’ in eight of the thirteen direct comparisons and was significantly lower in three of these. Average yield of ‘YRK4’ at 10.28 te/ha was 95% of ‘Millin’ (10.77) and ‘Namaga’ (10.85) and 99% ‘Amaroo’ (10.38) in these comparisons.

Physical Quality Attributes

Physical quality attributes were measured on research station trials in 1995 to 1998 and in trials in 1997 and 1998 where samples were taken over the maturity period.

Milling quality of ‘YRK4’ is generally superior to that of ‘Millin’, similar to that of ‘Koshihikari’ but inferior to ‘Amaroo’ and ‘Namaga’. This is consistent with maturity. Potential milling quality is equivalent to other medium grain varieties but, as with other short duration varieties, it should be harvested at high moisture (above 20%) for best results.

‘YRK4’ has fewer chalky grains than other comparative varieties. It has significantly less chalk than either ‘Millin’ or ‘Koshihikari’, the two varieties most suited to Japanese cuisine. It is also generally less chalky than either ‘Amaroo’ or ‘Namaga’ although it did record a higher level of chalk than these cultivars in one trial in 1997.

There is no evidence that ‘YRK4’ is significantly different from other comparative varieties for milled grain colour.

The general appearance of ‘YRK4’ is excellent as it has well shaped small short to medium grains and the milled grains are generally free from chalk and of good colour.

YRK4 and Koshihikari are both close to the FAO description of short grains (<5.0mm on milled rice). To avoid confusion within the Australian industry, we will refer to both Koshihikari and YRK4 as short grained varieties. In Japan, a different set of definitions are used and both Koshihikari and YRK4 would be classified as medium grain varieties.

Table 4. Quality results from Yanco replicated trials, 1995 to 1998. Quality was assessed after harvesting on the same day. Hd is days sowing to anthesis; WG% is whole grain %; Ch is chalkiness where, for 1995 it is indicated by score (higher number is less chalky) and for subsequent years is chalky area expressed as a percentage of total grain area; Yel is yellowness index where a lower value indicates whiter milled grain.

1995 1996 Variety Hd WG% Ch Yel Hd WG% Ch Yel YRK4 123 71 23 38.4 119 70 0.1 41.5 Millin 115 68 22 40.0 116 62 0.3 40.4 Amaroo 132 75 20 41.7 127 71 0.5 40.5 Namaga 127 73 22 41.4 125 72 0.9 42.4 lsd(p<0.05) 3 3 2 2 3 3 0.5 1.5

1997 1998 Variety Hd WG% Ch Yel Hd WG% Ch Yel YRK4 121 54 3.1 31.8 114 28 0.4 32.5 Millin 115 42 4.2 31.8 110 6 1.6 29.0 Amaroo 126 62 1.7 31.5 120 47 1.0 30.0 Namaga 125 60 2.8 31.2 120 60 3.4 33.5 Koshihikari 125 53 4.4 30.4 113 25 2.2 29.5 lsd (p<0.05) 2 8 1.5 1.0 2 12 0.5 3.0

Table 5. Results from YIQ trials where serial samples were taken. Characters are as for Table 4. WG% is the highest whole grain% recorded while the results over three harvest dates are averaged for chalk% and yellowness index.

1997 1998 Variety Hd WG% Ch Yel Hd WG% Ch Yel YRK4 120 63 1.1 32.8 110 72 0.8 38.8 Millin 115 48 3.6 32.8 110 67 2.8 38.6 Amaroo 125 69 1.8 31.4 122 73 2.0 38.5 Namaga 125 69 2.7 32.8 122 72 2.8 37.9 Koshihikar 120 65 3.5 31.7 111 62 3.4 38.5 i

Cooking Quality

Amylose content

Amylose content of ‘YRK4’ is low and similar to that of ‘Koshihikari’, averaging 19%.

Gelatinisation temperature

Gelatinisation temperature is low and similar to that of ‘Koshihikari’ and the medium grain cultivars. This is indicated by a value of 7 for reaction to 1.1% KOH.

Paste properties

The Newport Rapid Viscoanalyser (RVA) is used to compare pastes made from white rice flour and water. Viscosity curves are produced using a standard heating, cooking and cooling cycle. The pattern of the curves produced can be used to cluster varieties with similar cooking properties. Variations in the curve between samples of the same variety are due to environmental influences on starch properties or variations in protein and/or free fatty acid content. Figure 1 shows a range of YRK4 and Koshihikari samples from trial sites in the 1998 harvest compared in the RVA. The overlap of the two populations of curves is evident. When average curves for all pairs were compared, the result indicated that YRK4 was close but slightly firmer textured than Koshihikari during cooking and cooling.

Cooked rice texture

Texture is soft and remains soft as cooked rice cools. These results are influenced by protein content in a similar way to ‘Koshihikari’. Average Kramer Instron Texture are YRK4 (54.1 kg), Koshihikari (53.2 kg) and Millin (57.1 kg).

NIR “taste” analysis

In Japan several analytical instrument companies have produced dedicated near infrared reflectance (NIR) or transmittance (NIT) instruments that are correlated with Japanese taste panel estimates of cooked rice taste. Results are produced as a taste score and are widely used in Japan by rice mills, supermarkets and rice stores as an aid to selecting top quality rice.

An instrument based on the NIR Systems 6500 and calibrated for rice taste score by the Nireco Company of Tokyo was used to assess samples of experimental lines. These included YRK4, Australian grown Koshihikari and Millin on several occasions during the development of YRK4.

YRK4 gave consistent high readings in the range of 68 – 79 units. This was comparable with Australian grown Koshihikari (64 – 82 units) and much higher than Millin that never scored above 62 units in these tests. The results for YRK4 were stated to be the best seen for any non-Japanese bred variety by one of our collaborators in Japan.

Quality summary

Overall, quality is superior to Australian grown ‘Koshihikari’ due to its advantages in appearance and milling with similar cooking/eating quality characteristics.

Seed Production

NSW Agriculture will maintain breeders seed of line ‘YRK4’ and will continue to provide pure breeders seed for the life of the variety. Currently there is sufficient breeders seed to provide about 1 tonne from the 1999 harvest. Ricegrowers’ Co-operative Limited have sown approximately 870ha ‘YRK4’ in 1998/99. This is for commercial evaluation and seed increase.

An application for provisional PBR protection of this variety has been submitted.

Potential

‘YRK4 is a specialty variety with characteristics that make it suited to Japanese style cuisine. It is likely to be competitive in a portion of the rice for North Asia and parts of the domestic market, with potential markets also in Singapore and Hong Kong. At least in the short term, however, it is unlikely to replace all ‘Koshihikari’ which has a reputation for high quality in these markets.

The grain is smaller than current commercial medium grain cultivars (with the exception of ‘Koshihikari’) so co-mingling at receival will not be possible. For this reason, it is unlikely to become a mainstream cultivar and will be restricted to the small although expanding market for very soft cooking rice.

‘YRK4’ has relatively short duration. It should not be restricted to any portion of the NSW rice producing area for any agronomic reason.

Breeders

‘YRK4’ was bred by NSW Agriculture at Yanco Agricultural Institute. The breeding team was Laurie Lewin, Tony Blakeney, Russell Reinke and Melissa Fitzgerald with assistance from Colin Dunn, Alice Fiumara, Margrit Martin, Anne Sheldrick, John Smith, David Troldahl and Judy White.

Acknowledgments

The rice improvement program has received extensive support from the Rice Research Committee of the Rural Industries Research and Development Corporation (RIRDC). The development of YRK4 was particularly aided by research into quality attributes necessary for Japan and Korea and methods for their evaluation carried out with the aid of a grant from the McCaughey Memorial Trust, We thank the R&D and marketing staff of Ricegrowers’ Co-operative Limited for their perception on market requirements. Tony Blakeney thanks Ricegrowers’ Co-operative Limited and BRI Australia for the use of facilities necessary in the quality evaluation of this line.

Many rice growers have supported rice variety development through provision of land and management expertise for rice trials. Their support is gratefully acknowledged.

L.G. Lewin R.F. Reinke NSW Agriculture NSW Agriculture Yanco Yanco

A.B. Blakeney M. Fitzgerald BRI Australia NSW Agriculture Yanco

Koshihikari - Dark lines YRK4 - light lines