Developing Rices Suitable for Export to Japan

A report for the Rural Industries Research & Development Corporation

by A.B. Blakeney L.G. Lewin R.F.Reinke

August 2004

RIRDC Publication No 04/006 RIRDC Project No DAN-94A

ISBN 064258716 7 ISSN 1321 2656

Developing Rices Suitable for Export to Japan Publication No. 04/006 Project No. DAN-94A

The views expressed and the conclusions reached in this publication are those of the authors 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 unless authorised in writing by the Managing Director of RIRDC.

This publication is copyright. Apart from any fair dealing for the purposes of research, study, criticism or review as permitted under the Copyright Act 1968, no part may be reproduced in any form, stored in a retrieval system or transmitted without the prior written permission from the Rural Industries Research and Development Corporation. Requests and inquiries concerning reproduction should be directed to the Managing Director.

Researcher Contact Details L.G. Lewin NSW Agriculture Yanco Agricultural Institute PMB YANCO NSW 2703

Phone: 0269 512 713 Fax: 0269 557 580 email: [email protected]

In submitting this report, the researcher has agreed to RIRDC publishing this material in its edited form.

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 4819 Fax: 02 6272 5877 email: [email protected] Internet: http://www.dpie.gov.au/rirdc

Published in August 2004 Printed on environmentally friendly paper by Canprint

Foreword

RIRDC has had an important association with the rice industry of NSW over a long period. Much of the support has been given to aspects of rice improvement and grain quality.

The project discussed in this report was funded at a time when Australia did not sell rice to Japan. By the conclusion of the project, however, we were marketing rice into that country and an understanding of their preferences was important to us gaining a substantial share of the available market. As a result of this project one rice variety, Millin, was released specifically for Japan and this enabled the industry to gain market share.

RIRDC is pleased with its association with the Australian rice industry and satisfied that its contribution to the development of specific rice varieties for unique markets has significantly added to the profitability of the industry.

This project was funded from industry revenue which is matched by funds provided by the Australian Government

This report, an addition to RIRDC’s diverse range of over 1000 research publications, forms part of our RICE R&D program, which aims to improve the profitability and sustainability of the Australian rice industry.

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

• downloads at www.rirdc.gov.au/fullreports/index.html • purchases at www.rirdc.gov.au/eshop

Simon Hearn Managing Director Rural Industries Research and Development Corporation

iii

Acknowledgments

The authors wish to acknowledge the support of RIRDC and the Rice Research and Development Committee of RIRDC.

Many people contributed to aspects of this project. These represented the grain quality and rice improvement sections of Yanco Agricultural Institute. In particular Miss J. Reece, Miss L. Welsh, Mrs M. Martin, and Mrs J. White from the grain quality group made significant contribution. Representatives from the improvement group who contributed were Ms J. McIntosh, Mrs P. Emery, Mrs E. Sheldrick, Mr D. Troldahl, Mr C. Dunn, Mr F. Ciccia and Mr. G. Laing.

The support of the management and staff at Yanco Agricultural Institute and at the Deniliquin Field Station of NSW Agriculture was important to this work as was the services provided by the management and staff at the McCaughey Institute, Jerilderie. Those rice farmers who assisted by conducting trials of Millin on their property also contributed to the outcome of the project.

Contents Foreword...... iii Acknowledgments...... iv Executive Summary ...... vi

Introduction ...... 1

Objectives...... 1

Methodology ...... 2

Results ...... 3 1. Characteristics of Japanese Varieties ...... 3 1.1 Field Performance...... 3 1.2 Physical Quality ...... 4 1.3 Cooking Quality ...... 5 2. Breeding Program for Japanese Quality...... 7 3. Release of Variety YRM41 (Millin)...... 7 3.1 Grain Yield ...... 7 3.2 Agronomic Characters ...... 8 3.3 Milling Quality ...... 9 3.4 Grain Appearance ...... 9 3.5 Cooking Quality ...... 9

Discussion of Results ...... 11 1. Japanese Quality ...... 11 2. Texture Testing...... 11 3. Relase of Millin ...... 11

Implications...... 12

Recommendations ...... 12

Intellectual Property ...... 12

Communications Strategy ...... 12

Bibliography ...... 12

Executive Summary

A range of varieties, introduced from Japan, were compared with Australian commercial cultivars to determine characteristics of value for Japanese quality. They were also compared for field performance. Included in this set of varieties was Koshihikari, which is regarded as the premium quality rice variety in Japan.

No Australian grown variety, whether derived from Japan or Australia completely reproduced the texture characteristics of Japanese grown Koshihikari. Australian grown Koshihikari was not as “soft” as its Japanese grown counterpart.

While there were a range of quality attributes in the Japanese set, the Australian varieties were generally of similar quality and were only slightly firmer. All Australian cultivars, however, had slightly larger grain than those derived from Japan.

The Japanese variety Akihikari had high yield potential and its field performance approached that of the best Australian varieties. This variety had very chalky grain, however, and would not be acceptable in Japan. No other Japanese variety had a yield which would allow it to be grown commercially in Australia without a significant premium.

As a consequence of this work, and the improved understanding of the quality requirements for Japan, YRM41 was released to the rice industry as Millin in Australia and in Japan in March, 1995. It is a medium grain variety with grain quality that is more suited to the Japanese market than other Australian medium grain cultivars. Millin has lower chalk content and smaller grain size than other Australian medium grains. Although not meeting the full specifications for Japan, it is a move in the right direction.

Introduction At the commencement of this project the Japanese rice market had been closed to imports for over twenty years. There was some suggestion that the market may open with pressure under the Uruguay round of the GATT. Domestic rice prices in Japan were over eight times world price.

Australian medium grain rice varieties are ‘japonica’ types – derived originally from Japanese varieties. They are ‘soft’ cooking types with low amylose content and were considered suited to the lower quality, catering portion of the Japanese market.

No Australian rice had the appearance or cooking characteristics that would place it in the premium class in Japan. In 1992, over 60% of the Japanese market was classed as premium and there was a high demand for rice produced by the premium variety ‘Koshihikari’. Japanese buyers favour grain with smaller dimensions and lower levels of chalk than found in Australian rice. They were also able to discriminate small differences in cooked grain texture.

Texture assessment in the Australian breeding program was crude and required large quantities of grain. Texture assessment could not be used as a regular screening tool in the breeding program. Automated texture testing was required that would be regularly used at earlier generations of the breeding program.

There was only a poor understanding of the quality requirements for the Japanese market. Equally there was a requirement to determine the quality characteristics of key Japanese varieties so that Australian varieties with Japanese characteristics could be selected.

Objectives

The project aimed to:

• identify the best sources of Japanese quality • develop suitable techniques for estimating Japanese quality • create new lines for Japanese quality by introduction, hybridisation and selection • release varieties with Japanese quality.

Methodology

A survey of Japanese varieties had been made. Some of these had been introduced into Australia but they had not been assessed for Japanese quality when grown under Australian conditions. Some crosses had been made but none of the progeny had been assessed for qualities that would be acceptable to the Japanese.

Sensitive micro-texture testing equipment was to be purchased. This equipment was to be linked with a computer to allow testing of texture on small samples. The micro-texture test system was to be used as a replacement for the standard Kramer shear-cell attached to an Instron © texture tester (Blakeney, 1979). The final year of this project would see the equipment incorporated into the quality testing system.

A range of commercial samples from Japan and Australian grown Japanese varieties were tested for quality parameters. Particularly the Rapid Visco Analysis system was used (Blakeney et al, 1994) to estimate rice starch texture. The RVA measures starch paste viscosity through a heating, dwell, cooling cycle (Figure 1). Key parameters in this test are:

• apparent gelatinisation temperature, a measure of cooking time • peak viscosity, an estimate of texture • final viscosity, also an estimate of texture • set back – the difference between final and peak viscosity and a measure of the stickiness of cooked rice.

Figure 1: Typical RVA trace of starch paste viscosity showing key points

300 100

250 Peak Viscosity 90 Set Back 200 Final Viscosity 80 C o 150 70

RVA units RVA 100 Temperature 60 50 Gelatinisation

50 0 RVA units Temperature

40 02468101214 Time (min)

An improvement program to introduce Japanese quality into Australian cultivars was operated under this program. This particularly concentrated on estimating grain shape and size, chalkiness and cooked grain texture as estimated by RVA and texture analysis.

Results

1. Characteristics of Japanese Varieties

Varieties have been introduced into Australia from Japan over a long period. A subset of these varieties was chosen to represent those with some relevance to the Australian breeding program or those reputed to have acceptable quality in Japan (Table 1). These varieties were compared with two Australian medium grain cultivars for field performance and grain quality attributes.

Table 1 Japanese and Australian varieties selected for comparison of field and quality attributes.

Variety Year Introduced Reason for Inclusion Akihikari 1991 High yield in Japan and acceptable quality Akitakomachi 1991 High yield in Japan and acceptable quality Koshihikari 1985 The most popular variety in Japan and reputed to have the best quality Nippon Bare 1992 An older type variety. No longer considered to be a quality variety Sasanashiki 1988 Once considered a high quality variety but loosing favour Somewake 1965 Used as a parent in the Australian breeding program for early maturity and cold tolerance. Quality unknown. Amaroo Australian Semi-dwarf cultivar. The most popular Australian medium grain cultivar Calrose Australian An Australian medium grain cultivar which had been marketed in Japan in the past.

1.1 Field Performance

The varieties from Table 1 were tested under field conditions in trials at Yanco Agricultural Institute in 1992/93 and 1993/94 seasons (Table 2). The Japanese varieties ranged from earlier to similar in maturity to the Australian varieties. Amaroo was higher yielding than any Japanese cultivar. Akihikari was the highest yielding cultivar from Japan and yielded more than Calrose. Sasanashiki was low yielding but also appeared to be very cold susceptible in the cold affected trial of 1992/93. Koshihikari was of intermediate yield but appeared to be relatively resistant to cold.

Table 2 Days from sowing to anthesis (mean of two trials) and grain yield (tonnes/ha at 14% moisture) in two trials at Yanco Agricultural Institute 1992/93 and 1993/94.

Variety Head date 1993 Yield 1994 Yield Akihikari 113 10.5 9.5 Akitakomachi 115 4.3 5.5 Koshihikari 123 8.0 8.5 Nippon Bare 120 5.1 5.0 Sasanashiki 124 3.5 6.8 Somewake 103 5.2 6.2 Calrose 122 9.5 8.9 Amaroo 125 11.1 10.9 lsd (p<.05) 2** 1.0** 1.1**

1.2 Physical Quality

Typical physical quality attributes are length, width, grain weight, milling quality and chalkiness. All Japanese varieties tested with the exception of Somewake had small medium grains (Table 3). Somewake is a true short or pearl grain and is more rounded than other varieties tested as indicated by length/width ratio and grain weight. Koshihikari, the most favoured Japanese variety, was smaller than other medium grain varieties in both length and grain weight. Both Calrose and Amaroo have true medium grains and are generally larger than the Japanese varieties. They are considered too large for true Japanese quality. YRM41, while not as short as the Japanese varieties, is closer to the grain dimensions required in Japan.

Table 3 Length and width of brown grains (mm) of nine rice varieties. Also variation for length and width as measured by standard deviation of a 30 grain sample. Thousand grain weight of both paddy and brown samples is in gm.

Variety Length sd Width sd Paddy Brown mm length mm width g/1000 gr g/1000 gr Akihikari 5.27 0.20 2.92 0.18 23.6 20.0 Akitakomachi 5.50 0.24 2.80 0.20 22.4 19.3 Koshihikari 5.22 0.19 2.98 0.20 21.9 18.7 Nippon Bare 5.36 0.19 3.00 0.19 24.3 20.0 Sasanashiki 5.28 0.21 2.93 0.13 22.6 19.3 Somewake 5.11 0.23 3.11 0.27 26.2 22.0 Amaroo 5.94 0.19 2.88 0.10 24.4 20.7 Calrose 5.99 0.27 2.81 0.13 23.8 19.6 YRM41 5.62 0.20 2.80 0.18 23.8 19.3

Milling quality of the Japanese varieties was generally poor under NSW conditions (Table 4). In most cases this was related to maturity with earlier maturing varieties having lower final % whole grain due to greater field exposure to weathering. The level of chalk was relatively high for most varieties. Akitakomachi and Sasanashiki were less prone to chalk but other Japanese varieties were inferior to Amaroo and Calrose.

Table 4 Whole grain % after milling for eight rice varieties. Potential whole grain was highest recorded and weathered whole grain was after drying in the field to low moisture. Chalkiness % was measured as the % grains with >50% chalk. The mean of two experiments.

Whole Grain % Variety Chalk % Potential Weathered Akihikari 60 14 14.1 Akitakomachi 62 9 0.8 Koshihikari 65 40 2.3 Nippon Bare 62 38 2.5 Sasanashiki 64 45 0.4 Somewake 58 25 1.5 Amaroo 65 58 0.8 Calrose 64 55 1.2 lsd(p<0.05) 4** 8** 0.5**

1.3 Cooking Quality

Amylose content and the alkali reaction test was determined with this variety set. Lower amylose content is preferred in Japan. The reaction of milled grain to dilute potassium hydroxide is indicative of gelatinisation temperature. Generally the reaction to 1.1% alkali should be 6 or 7 for a Japanese variety and this indicates a low gelatinisation temperature. All varieties had quality that would suit them to the softer cooking market (Table 5). They had low amylose content and low gelatinisation temperature. Koshihikari did, however, have lower amylose content and would be expected to cook softer.

Table 5 Amylose content and alkali reaction score for eight rice varieties. The mean of 4 replicates from the 1992/93 trial

Amylose content Alkali reaction Variety % Score Akihikari 19.5 6.5 Akitakomachi 20.1 6.3 Koshihikari 18.2 7.0 Nippon Bare 19.1 7.0 Sasanashiki 19.5 6.8 Somewake 20.0 7.0 Calrose 20.1 7.0 Amaroo 19.8 6.8 lsd (p<.05) 1.0** 0.5 n.s.

All varieties were compared by Rapid Visco Analysis (RVA). The measured parameters related to those as outlined in Figure 1. Japanese grown Koshihikari had very different RVA characteristics than when grown in Australia (Table 6). It appeared to be softer cooking with a higher peak viscosity and more negative set back. There was little difference between all varieties when grown at Yanco. They are all classified as ‘soft’ cooking with low amylose (as indicated by negative set back) and low gelatinisation temperature. Amaroo tended to be firmer than the Japanese varieties but this difference was very small.

Table 6 RVA values for eight varieties of rice. Gel Temp. is apparent gelatinisation temperature as measured from the RVA curve. Peak, Final and Set back relate to the parameters in Figure 1 and are in RVA units. Koshihikari(J) is Japanese grown Koshihikari. All other varieties were grown at Yanco Agricultural Institute.

Variety Gel Temp. Peak Final Set back Akihikari 68 220 185 -35 Akitakomachi 68 197 180 -17 Koshihikari 68 192 174 -18 Nippon Bare 68 205 190 -15 Sasanashiki 68 217 190 -27 Somewake 68 225 180 -45 Amaroo 68 210 197 -13 YRM41 68 222 206 -16 Koshihikari (J) 70 283 192 -91 The standard test for texture is the Instron texture test using a Kramer shear-cell (Blakeney, 1979). This test has a requirement for 100g grain and can only be used at later stages of the breeding and testing program when the lines are relatively pure. A Lloyd LR5K© tester was purchased for use in this project as it could be connected to a computer and would be adaptable to more extensive testing.

The varieties were subjected to the standard test after cooking by the absorption method as described by Blakeney (1979). Japanese varieties appeared softer when compared for cooked rice texture. Koshihikari was significantly softer than other varieties (Table 7) and the Australian cultivars appeared to be significantly firmer than the Japanese cultivars. It was concluded that shear-cell texture was able to discriminate the texture differences as indicated by Japanese preference.

Table 7 Kramer shear-cell texture of eight rice varieties. All varieties were grown at Yanco Agricultural Institute and there were 4 replicates.

Kramer shear-cell texture Variety Kg Akihikari 58.5 Akitakomachi 56.2 Koshihikari 52.3 Nippon Bare 59.1 Sasanashiki 56.1 Somewake 62.0 Calrose 63.5 Amaroo 63.3 Lsd (p<.05) 2.1**

2. Breeding Program for Japanese Quality

During the course of this project a breeding program to produce varieties for Japanese quality was initiated. Quality screening was incorporated specifically to select for grain shape and size, chalkiness, amylose content and cooked grain texture. Texture was initially to be screened by Rapid Visco Analysis and finally through analysis of texture using the Lloyd texture analyser. Table 8 indicates the numbers included in the breeding program at each generation for the three years of the project.

Table 8 Numbers of lines at each generation which aim specifically at selection for Japanese quality from 1992/93 to 1994/95.

Crop Year Generation 1993 1994 1995 Cross 4 12 26 F2 Populations 8 4 12 F3 Rows 1085 1200 1260

3. Release of Variety YRM41 (Millin)

YRM41 was released to the rice industry as Millin in Australia and in Japan in March, 1995. It is a medium grain variety with grain quality that is more suited to the Japanese market than other Australian medium grain varieties. Quality testing of the line YRM41 was carried out under this project and using some of the techniques developed in understanding quality for the Japanese market.

YRM41 was derived from a 1981 cross, designated YR81003 between M7 and the Japanese variety Somewake. F1 plants from this cross were subsequently backcrossed to M7 in 1982. After pedigree selection and preliminary testing, the district evaluation commenced in 1992 and continued through 1995. Quality evaluation also occurred during this period.

3.1 Grain Yield

YRM41 was compared with other commercial medium grain cultivars in 15 district trials from 1992 to 1994. The varieties that were included in these trials varied over the years and no variety was compared with YRM41 in all comparisons. This was because: YRM41 is of shorter duration than the main medium grain cultivars Amaroo and Bogan so direct comparisons were difficult The most direct comparison was with the cultivar Echuca but it had been discontinued as a commercial cultivar after 1992.

In general, grain yield was equivalent to that of Amaroo, Bogan, Echuca and Jarrah but below that of Illabong (an arborio style rice) (Tables 9, 10 and 11). YRM41 tended to perform better under conditions of low temperatures where its shorter duration and possible cold tolerance gave it an advantage.

Table 9 Grain yield (tonne/ha at 14% moisture) in district trials in 1992.

Site Cultivar Leeton Griffith Coleambally Deniliquin Finley Barham Mean YRM41 13.6 11.9 11.4 5.2 11.6 11.4 10.9 Echuca 12.4 12.8 11.9 3.0 11.5 11.1 10.5 Jarrah 12.7 11.4 11.9 8.0 11.7 9.0 10.8 lsd(p<.05) 1.2* 1.3* 1.8ns 2.1** 1.7ns 2.1* Ns

Table 10 Grain yield (tonne/ha at 14% moisture) in district trials in 1993

Site Cultivar Finley Barham Griffith Coleambally Leeton YRM41 9.8 11.2 9.7 10.7 9.0 Amaroo 4.6 10.2 Bogan 10.2 11.0 8.2 Illabong 11.4 11.8 11.1 12.3 10.5 lsd(p<0.05) 1.1** 1.6* 1.8ns 0.9** 2.0*

Table 11 Grain yield (tonnes/ha at 14% moisture) in district trials in 1994.

Site Cultivar Griffith Finley Barham Deniliquin Mean YRM41 9.2 9.7 8.8 8.8 9.1 Amaroo 9.9 - - - 9.9 Illabong 10.7 12.2 10.0 9.7 10.7 lsd (p<0.05) 0.9** 0.7** 0.6** 0.8*

3.2 Agronomic Characters

Agronomic characteristics are summarised in Table 12 . YRM41 is a semi-dwarf variety. Its height was similar to Amaroo, Bogan and Echuca but shorter than Jarrah. It is therefore less prone to lodging than Jarrah but will lodge under very fertile conditions.

YRM41 is approximately 5 to 7 days earlier than Amaroo to flower and 7 to 10 days later than Jarrah. This is a distinct advantage for the variety and will allow early harvesting of YRM41 to facilitate early marketing in Japan.

Seedling vigour of YRM41 is similar to that of Amaroo but below that of Jarrah. YRM41 has given poor seedling growth when sown early under very cold conditions. Since it is of shorter duration than Amaroo, it would normally be sown later and hence is likely, on average, to experience more favourable conditions for establishment.

Table 12. Plant height (Ht) in cm from ground to extended panicle at maturity; duration (Hd) in days from sowing to flowering; and establishment (Est) as plants per square metre. All characters measured on five research station trials from 1992 to 1995.

Cultivar Ht Hd Est YRM41 80 102 208 Amaroo 81 109 218 Echuca 80 105 195 Jarrah 86 95 225 Lsd (p<0.05) 2** 2** 10**

3.3 Milling Quality

Milling quality was measured in 1993 and 1994 on Amaroo and Millin where samples were taken over the maturity period (Table 13). Milling quality of YRM41 generally did not have the potential whole grain return of Amaroo and was below that of Amaroo in 1993. Milling quality of YRM41 also declined more quickly than that of Amaroo. Generally, however, the milling performance of YRM41 was better than that of Jarrah. This was consistent with the maturity difference of the varieties. The shorter duration varieties would generally be exposed to higher temperatures over the period they were standing in the field and hence be more susceptible to cracking and grain breakage on milling. The results do highlight the importance of early harvest, however, particularly for the varieties of shorter duration.

Table 13 Whole grain percentage for three varieties of rice in two years of sampling (1993 and 1994). Results are presented as potential whole grain and matured whole grain %.

1993 1994 Cultivar Potential Low Potential Low YRM41 69 50 90 58 Amaroo 72 70 70 58 Jarrah 65 31 70 59

3.4 Grain Appearance

Grain appearance was assessed on each of the samples used in the milling quality study. Appearance was appraised subjectively (Table 14). Chalkiness, the opaque area in milled grain, is an undesirable character for rice for Japan. These were assessed subjectively by scoring 0 to 9 on the basis of chalk. A score of 7 or higher indicates a low proportion of chalk in the sample. YRM41 averaged consistently better for chalk than either Amaroo or Jarrah in both years.

Grain dimensions were measured on the brown rice for the three varieties. Millin was consistently smaller than either Amaroo or Jarrah. This is a desirable trait for rice for Japan.

Table 14 Grain appearance results for YRM41, Amaroo and Jarrah. Length and width is in mm and measured on 20 grain samples on brown rice. Grain weight (Gwt) is the mass of 1000 grains (paddy at 0% moisture). Chalkiness is score from 0 to 9 where the higher number has less chalk.

Cultivar Length Width Gwt 1993 Chalk 1994 Chalk YRM41 5.6 2.8 22.0 6.7 7.0 Amaroo 5.9 2.8 22.9 6.6 6.5 Jarrah 6.0 2.8 23.1 6.3 6.7 Lsd(p<0.05) 0.2** 0.1ns 0.4** 0.2** 0.2*

3.5 Cooking Quality

The cooking qualities of YRM41 were assessed by direct cooking by both the excess water and absorption methods, by rapid visco-analyser and by Instron texture measurements of cooked grain texture. The proportion of endosperm starch which is present as amylose can have a significant effect on the texture of cooked rice. The amylose content of YRM41 was assessed during the breeding process on harvested grain from a pure seed panicle row. YRM41 had the same amylose content as Amaroo (Table 15). The cooking time was determined by sequentially removing grains from a sample during cooking and compressing the grain between microscope slides so the uncooked core of the grain is visible.

The cooking time is assessed as the time at which the entire grain is gelatinised and the core is no longer visible. With this test the optimum cooking time for Amaroo and YRM41 was identical at 16 minutes. Despite having slightly smaller grains there was no change in the cooking time required for YRM41. The alkali spread score reflects the gelatinisation temperature and, as shown in Table 15, there is no significant difference between Amaroo and YRM41.

Table 15 Cooking quality tests on Amaroo and YRM41. Results are for cooking time (minutes), amylose content (%) and alkali spread (score).

Cultivar Cooking time (min.) Amylose content Alkali spread % Score Amaroo 16 22.6 6.8 YRM41 16 22.5 6.6 Jarrah 17 23.3 6.7

Comparative Rapid Visco Analyser traces of YRM41 and Amaroo demonstrate that apart from a slightly lower peak viscosity than Amaroo, the traces for both varieties are very similar. A more sensitive measure for the differences in cooked grain texture is provided by the Instron texture tester. These results are shown in Table 16 and demonstrate clearly that the cooked grain texture of YRM41 is softer than that of Amaroo.

Table 16 Results of the Instron texture test (in kg.) of Amaroo and YRM41 after absorption cooking.

Variety Sample 1 Sample 2 Sample 3 Mean Amaroo 63.5 62.0 64.5 63.3 YRM41 58.0 55.5 56.0 56.5

Discussion of Results

1. Japanese Quality

Japanese varieties retain their soft cooking character when grown in Australia. This was reflected in direct measure of texture as evidenced by the Kramer shear-cell estimates. It was not so evident in RVA measures of paste viscosity or direct measures of amylose content.

There was a large difference, however in the RVA trace for Koshihikari when grown in Australia and in Japan. While there were also some differences in acceptability, these were not as great as could be predicted from the RVA. Clearly comparisons of RVA traces should only be made on rice grown under similar conditions.

Grain size and shape was important. Australian cultivars have longer grain and tend to be heavier than those from Japan. Clearly selection should be towards smaller grain for Japanese quality.

Freedom from chalkiness is also important. Unfortunately most Japanese cultivars produce relatively high chalk levels when grown in NSW. Sasanashiki and Akitakomachi have low chalk levels but they are not productive under NSW conditions. Akihikari had acceptable yield under NSW conditions but very chalky grain. Koshihikari had the best Japanese quality under local conditions and yield levels were moderate. Although chalkiness of Koshihikari is slightly high, it is the best prospect as a premium quality variety if a subsidy for this type of rice is available.

2. Texture Testing

Direct measures of texture are required to clearly discriminate Japanese quality. The Lloyd LR5K texture tester lends itself to such tests and should be incorporated as a regular component of testing for Japanese quality.

3. Relase of Millin

Millin is a variety that will partially satisfy the need for softer cooking Australian rice. It does not meet all quality criteria for premium Japanese quality as grain is slightly long and texture is not as soft as that of Koshihikari.

Implications

If a premium Japanese rice is required, only Koshihikari is likely to meet the productivity and quality requirements. Millin will meet a demand for moderate Japanese quality but cannot meet the premium market.

Grain size, chalkiness and texture are the main quality requirements for Japan. These characteristics will be emphasized in the selection program that is aimed at development of premium quality varieties for Japan.

Recommendations

2. Investigate the use of Koshihikari as a premium rice for Japan.

3. Use Millin as a variety of moderate quality for the bulk Japanese market.

4. Increase pressure on development of a premium quality variety for Japan that has yield potential of Australian commercial cultivars.

5. Emphasise grain size and freedom from chalk in a selection program for Japanese quality.

6. Incorporate texture testing as a regular component of the selection process.

Intellectual Property

Plant breeders rights were not sought for Millin, and there are no intellectual property issues arising from the work.

Communications Strategy

Implications for the improvement program have been incorporated into the selection program and further communication is not required.

There is a demand for Millin as a shorter duration variety which is more productive and reliable than Jarrrah. Producers are fully aware of this variety through meetings, field days and the variety brochure that accompanies the seed circular each year.

Bibliography

Blakeney, A.B. 1979. Instron measurement of cooked-rice texture. In Proceedings of Workshop on Chemical Aspects of Rice Grain Quality. IRRI, Manila pp343-353.

Blakeney, A.B., Welsh, L.A., Reece, J.E., Lewin, L.G. and Reinke, R.F. 1994. Selection of rice cooking characteristics using RVA paste viscosity curves. In: Proceedings of the 44th Australian Cereal Chemistry Conference. Panozzo, J.F. and Downie, P.G. eds. Ballarat. pp 114-117.