The assessment of the fragrant trait in a collection of vietnamese rice landrace varieties

INTRODUCTION

Preface

Rice (Oryza sativa L.) is the world's most vital food crop, consumed more than any other by humans It serves as a staple food in Asia, home to nearly half of the globe's poorest population, and is increasingly becoming a crucial food source in Africa and Latin America.

As global living conditions improve, the demand for high-quality rice is increasing, with fragrance being a key factor in selecting premium varieties This has prompted researchers to focus on the genetic analysis of rice fragrance, making it a target in modern breeding programs In Vietnam, fragrant rice landraces are primarily found in the Northern and Southern regions, with notable varieties such as Nang thom cho Dao and Nang huong in the South, and Tam thom and Tam xoan in the North These valuable rice resources must be conserved and utilized sustainably.

Research has identified numerous volatile fragrance-forming chemicals in rice, including hydrocarbons, alcohols, aldehydes, esters, and ketones (Yajima et al., 1978; Widjaja et al., 1996; Ma Thai Hoa and Le Ngoc).

2-acety-1-pyrroline (2AP) is crucial for the aromatic quality of fragrant rice varieties, as highlighted by multiple studies (Thach, 2011; Buttery et al., 1982; 1983; Paule et al., 1989; Laksanalamai and Ilanganntileke, 1993) Fragrant rice contains approximately 0.09 mg/kg of 2AP, which is ten times the amount found in non-fragrant rice, where levels range from 0.006 to 0.008 mg/kg (Buttery et al., 1983).

A recessive gene on chromosome 8, encoding the enzyme betaine aldehyde dehydrogenases 2 (BADH2), significantly influences the biosynthesis of 2-acetyl-1-pyrroline (2AP) (Bradbury et al., 2005a) The functional BADH2 protein inhibits 2AP production in non-fragrant rice, while non-functional alleles lead to 2AP accumulation in fragrant rice (Chen et al., 2008; Niu et al., 2008) Notably, major allelic variations of the Badh2 gene, including an 8-bp deletion in exon 7, are strongly linked to fragrance.

2 al., 2005a), a 7-bp deletion in exon 2 (Shi et al., 2008), an 803-bp deletion between exons 4 and 5 (Shao et al., 2011)

Recent advancements in detecting mutation types of the Badh2 gene have led to the use of molecular-associated markers (MAS) to aid breeders in selecting for fragrance While rice breeding programs in Vietnam have successfully released numerous high-quality rice varieties, the genetic diversity of the Badh2 gene in fragrant rice varieties remains unreported Additionally, Vietnamese rice faces stiff competition from neighboring countries like Thailand and China in the market.

In response to the challenges faced and with the aim of enhancing the quality of Vietnamese rice, I initiated a project titled “Genetic diversity assessment of fragrant trait in a collection of Vietnamese rice landrace varieties.” This endeavor was undertaken under the guidance of Dr Hoang Thi Giang and Dr Nguyen Thi Lam Hai, as part of the Root team at LMI-RICE.

Objectives

The aim of the project is to characterize a collection of 182 Vietnamese rice landrace varieties for phenotypic and genetic diversity of fragrant trait using sensory test and molecular markers.

Requirements

- To evaluate fragrance of the collection of Vietnamese rice landrace varieties

- To identify mutation types of Badh2 gene associated with fragrance in the collection of Vietnamese rice landrace varieties by using functional markers

- To select promising high-quality fragrant local rice varieties for rice breeding program

LITERATURE REVIEW

Rice grain quality

Rice milling is a crucial process that removes hulls and brans from paddy grain, resulting in polished rice and significantly influencing rice quality and value (Bao, 2018) To cater to consumer preferences, rough milling transforms rough rice into milled or polished grain by eliminating the hulls and bran from dried rough rice, which typically contains about 14% moisture, while minimizing grain breakage The commercial milling system consists of multiple processing stages, beginning with de-husking to remove the husk, followed by polishing to eliminate bran layers and enhance the surface gloss of the edible white portion (Bao, 2018).

The quality and efficiency of the milling process are evaluated based on three key parameters: brown rice recovery (BRR), milled rice recovery (MRR), and head rice recovery (HRR), which represent the percentages of brown rice, milled rice, and head rice to rough rice, respectively (Bao, 2018) A study conducted in 2002 comparing three lab mills—IRRI Test Tube Mill, Kett Polisher, and McGill No 2 Mill—found that the IRRI Test Tube Mill, despite requiring longer milling durations, effectively achieves desired bran removal through a gentle milling action, making it more efficient than the Kett Polisher and comparable to the McGill No 2 Mill (Bautista and Siebenmorgen, 2002).

Figure 2.1 Images of rice kernels milled with the three indicated laboratory mills showing the effect of each machine on the shape and size of milled rice kernels

The milling quality of rice is influenced by several factors, including the genetic differences among rice cultivars, environmental conditions during growth, milling machinery, and milling technologies (Bao, 2018) Among these, the genetic characteristics linked to different genotypes are the most significant determinants of milling quality This indicates that milling quality is genetically controlled and can be enhanced through breeding efforts Consequently, achieving a high head rice yield (HRY) is a key goal for rice breeding programs (Nelson et al., 2011).

The rice market is increasingly competitive, with consumers prioritizing various criteria for selecting high-quality rice, particularly focusing on the visual characteristics of rice grains such as dimensions, chalkiness, color, and whole grain recovery The appearance quality significantly influences the evaluation and pricing of rice varieties in the market, making it essential to obtain accurate information regarding these visual attributes According to Zhou et al (2019), a rice grain is composed of a hull.

Rice consists of several components, including lemma and palea, bran layers (pericarp, aleurone, subaleurone layers), embryo, and endosperm The term "brown rice" refers to rice with its brown bran layer intact, while "white rice" is produced by removing the outer bran layer, which results in a loss of fiber, vitamins, minerals, and amino acids The polishing process further removes the bran layers and embryo, leading to the commonly consumed form of rice, known as "white rice." Key physical properties of rice include grain size and shape, chalkiness, translucence, and color, with grain size encompassing length, width, and thickness.

Indica rice is characterized by its long and slender grains, while japonica rice features short and round grains However, certain varieties, like the short slender Samba Mahsuri, are highly favored, particularly in Southern India (Sundaram et al., 2008).

Figure 2.2 Genetic diversity of appearance quality

A: Brown rice with different colors; B: White rice with different grain shape and size Scale bar represents 3 mm; C: Three kinds of chalkiness in rice (Zhou et al., 2019)

Unlike other staple cereals such as wheat and maize, which are consumed as flour, rice is primarily used in its polished grain form, making the quality characteristics of rice grain crucial According to Champange et al (2004), starch is the main component of milled rice, accounting for about 78% (14% moisture) or 90% (dry weight) of the endosperm The properties of starch significantly influence the cooking and eating quality of rice To assess the cooking and sensory properties of rice grain, three key starch traits must be considered: apparent amylose content (AAC), gelatinization temperature (GT), and gel consistency (GC) (Sharma and Khanna, 2020).

The amylose content (AAC) of starch varies significantly between different types of rice, comprising 0.8 to 1.3% in waxy rice and 37% in non-waxy rice (Champagne, 2004) This variation in AAC is directly related to key quality indices of cooked rice, including cohesiveness, tenderness, stickiness, and glossiness.

6 the AAC value, rice can be classified as waxy (0-2%), very low (3-9%), low (10- 19%)., intermediate (20-25%), and high (>25%) (Champagne et al., 1999)

The Gel consistency index, as tested by Cagampang et al (1973), effectively highlights the differences among various rice varieties This test aims to elucidate the dissimilarities in rice characteristics.

The gelatinization characteristics (GC) of rice varieties are influenced by the ratio of amylose solubility in hot water, specifically the comparison between hot water soluble and insoluble amylose According to IRRI (2013), the GC index is determined by the length of the flour gel after hot water processing, categorizing rice into three groups: hard and very flaky (≤ 40mm), medium and flaky (41-60mm), and soft (>61mm) Varieties with a higher proportion of hot water insoluble amylose tend to exhibit a hard GC (Bhattacharya, 2009; Bhattacharya et al., 1978) Additionally, research indicates that long-chain amylopectin remaining in gelatinized starch granules may represent the hot water insoluble amylose (Takeda et al., 1987; Horibata, 2004).

(1994), amylose and protein content, amylose-graphic characteristics and even palatability showed significant difference depending on the position of spikelet in a panicle

Rice serves as a staple food, primarily providing energy through its high starch content In addition to starch, milled rice contains essential macronutrients, including storage proteins (7%), minimal storage lipids ( when used a high amount of sample, need better phase separation)

- Carefully transfer 100 àL of supernatant to a new 1.5 ml microtube

- Add 100 àL of isopropanol and mix by inversion several times, keep (- 200C) for 30 min

- Centrifuge microtube at 3000g (~ 5700 rpm) for 15 min at room temperature (4°C is better)

- Discard the supernatant and wash the pellet with 200 àL of 70% ethanol (v/v) by 2 times (centrifuge 1st time: 5700 rpm and 6 min, 4°C) (centrifuge 2nd time: 5700 rpm and 3min, 4°C)

- Air dry the pellet (or heat at 60°C – 5 min)

- Dissolve in 30 - 50 àL Milli-Q H2O or TE

- Store the stock solution in -20°C

Quality and quantity of extracted DNAs were done with agarose gel electrophoresis and with a Nanodrop

To investigate the presence of mutations in the Badh2 gene within the rice collection, we conducted a polymerase chain reaction (PCR) The PCR reaction mixture consisted of 20 µL, including 2 µL of Dream Taq buffer, 0.5 µL of 10 mM dNTPs, 0.2 µL of Dream Taq polymerase, 2 µL of 10 mM forward primer, 2 µL of 10 mM reverse primer, 1 µL of genomic DNA, and 12.3 µL of H₂O Amplifications were carried out using a thermal cycling program set at 95°C for 5 minutes.

30 cycles of 1 min at 94°C, 1 min at the annealing temperatures for individual markers, and 1 min 30s at 72°C with a final extension at 72°C for 10 min

RESULTS AND DISCUSSION

Evaluation of fragrance for the collection of Vietnam rice landrace varieties

A sensory test using a KOH-based method was conducted to evaluate the fragrance in 181 out of 182 rice varieties, following the fragrance assessment criteria provided by IRRI (2013) The popular commercial varieties Bac Thom 7 and Khang Dan 18 served as controls, and the results are detailed in Table 4.1.

Figure 4.1 Preparation of samples for sensory evaluation of fragrance

“+”: Bac Thom 7; “-”: Khang Dan 18; A, B: Samples submerged in KOH 1N; C: Grinding rice; D: Adding KOH 1N into petri dishes

Table 4.1.Fragrance score of the Vietnamese rice landraces collection

Table 4.1 The tab le of all data collected in thi s proj ect

No G_ID Fragrance score No G_ID Fragrance score

The fragrance scores of the studied rice collection ranged from 0 to 1.7, with G39 achieving the highest score of 1.7, while the positive control, Bac Thom 7, also scored 1.7 The varieties were classified into three groups: non-fragrant, slightly fragrant, and fragrant Out of 181 Vietnamese rice landraces evaluated, only 4 were categorized as fragrant, 14 as slightly fragrant, and the remaining 163 as non-fragrant Consequently, 90.06% of the varieties in the collection were non-fragrant, with fragrant varieties comprising just 9.94%.

Table 4.2 The statistic result of the fragrant test by the sensory evaluation

Percentage of the rice collection (%)

Among 18 varieties with fragrance identified, 10 are Japonica rice, including

The article discusses various rice varieties, highlighting that among the fragrant types, only six are classified as Indica rice: G132, G161, G173, G3, G39, and G57 Notably, three of these, G132, G39, and G57, are glutinous rice Additionally, two varieties, G108 and G24, are part of the admix group known as Tám rice Out of a total of 163 non-fragrant varieties, 52 are identified.

The study revealed that the majority of fragrant rice varieties in the collection are Japonica, while Indica varieties predominantly exhibit non-fragrant traits Notably, fragrant Indica varieties, such as Basmati and Jasmine rice, are primarily found in specific regions, with Basmati rice traditionally cultivated in India and Jasmine rice originating from Thailand Additionally, most glutinous rice varieties in the collection belong to the Japonica group, leading to a significant presence of fragrant Japonica varieties.

Identification of mutation types of Badh2 gene associated with fragrance in the

the collection of Vietnamese rice landrace varieties by using functional markers 4.2.1 Total genomic DNA extraction

To genotype the Badh2 gene linked to fragrance in the rice collection, the complete DNA templates for PCR are crucial Any disruption in the DNA templates can lead to errors in the analysis In our experiments, we extracted genomic material from 2-5 cm leaf pieces taken from each plant.

DNA After that, all extracted samples were checked by gel electrophoresis with agarose 1% (Figure 4.2)

The quality of the extracted DNAs, as shown in Figure 4.2, was generally good, with banding patterns exhibiting similar sizes and clear features Although there was slight contamination with organic compounds or RNA, the bands were deemed acceptable for subsequent PCR experiments.

Figure 4.2 Electrophoresis of extracted total genomic DNAs

L: Ladder 1kb, 1-9: Extracted DNA templates

Firstly, the extracted DNAs from the study rice collection were amplified with marker badh2-E7 to detect 8-bp deletion mutation in exon 7 of the Badh2 gene

(Bradbury et al., 2005a) The marker badh2-E7, containing 4 primers ESP, IFAP,

The badh2-E7 marker is co-dominant, making it effective for distinguishing between homozygous and heterozygous varieties of rice based on fragrance PCR products from badh2-E7 are analyzed on agarose gels, revealing three possible outcomes: a positive control band of approximately 580 bp for both fragrant and non-fragrant varieties, a 355 bp band indicating a homozygous non-fragrant allele, and a 257 bp band indicating a homozygous fragrant allele Additionally, the presence of both bands signifies a heterozygous non-fragrant allele This experiment utilized the badh2-E7 marker to conduct PCR on DNA samples from the entire rice collection, with results detailed in Table 4.3.

Figure 4.3 PCR banding patterns for functional marker badh2-E7

L: Ladder 1kb, “+”: Positive control Bac Thom 7, “-”: Negative control Khang Dan 18, 1-6:

Several representatives of the rice collection

Table 4.3 PCR results for checking mutations in Badh2 gene

No G_ID Molecular markers Mutation types of badh2-E7 FMbadh2-E4-5 badh2-E2 Badh2 gene

1 BT7 + - - 8-bp deletion in exon 7

32 G132 + - na 8-bp deletion in exon 7

8-bp deletion in exon 7 and 803-bp deletion between exons 4 and 5

82 G190 - + na 803-bp deletion between exons 4 and 5

115 G25 - + na 803-bp deletion between exons 4 and 5

149 G61 - + - 803-bp deletion between exons 4 and 5

14 mutants of 8-bp deletions in exon 7

6 mutants of 803-bp deletions between exons

No mutants of 7-bp deletion in exon 2 detected

“+”: PCR positive, “-”: PCR negative, “na”: not available

PCR analysis indicated that G26 is a distinct variety exhibiting three separate banding patterns of 580, 355, and 257 bp, suggesting it is heterozygous and non-fragrant Additionally, this study found that the majority of the rice collection is homozygous for fragrance.

A total of 14 varieties exhibited two banding patterns of 580/257 bp, which were comparable to the positive control Bac Thom 7, thereby confirming the presence of an 8-bp deletion mutation in exon 7, identified as the fgr allele The varieties included are G108, G132, G142, G154, G161, G177, G178, G200, G203, G211, G214, G220, G24, and G50.

14 exon 7-mutated varieties, there were three Indica varieties (G132, G142 and G211), two admix varieties (G108 and G24), the others are Japonica

Fragrance in rice is primarily caused by the loss of function of the Badh2 gene located on chromosome 8, as noted by Bradbury et al (2005a) The main allele linked to this fragrance trait is characterized by an 8-bp deletion and three SNPs in exon 7 of the Badh2 gene (fgr), according to He et al (2015) Additionally, the marker ESP+IFAP+ INSP+ EAP is relevant in this context.

The (badh2-E7) marker, developed by Bradbury et al (2005b), has been effectively utilized to identify mutations in rice collections, as demonstrated in various studies Notably, Duong Xuan Tu et al (2014) conducted research to evaluate the effectiveness of molecular markers in detecting an 8-bp deletion in exon 7 Their findings indicated that the marker ESP+IFAP+INSP+EAP exhibited high accuracy and stability, identifying 92-95% of fragrant individuals, including homozygous fragrant varieties.

A study on fragrant rice in India confirmed that the marker ESP+IFAP+INSP+EAP is among the most suitable for marker-assisted selection programs (Rai et al., 2015).

In comparison with these representations in the reference world collection, of

Our collection features 18 fragrant varieties identified through sensory testing with KOH 1N, revealing that 10 varieties (58.82%) carry the fgr allele This suggests that 8 additional varieties may harbor different mutant alleles of the Badh2 gene associated with fragrance Interestingly, four varieties (G142, G203, G211, and G220) exhibited no fragrance despite having the fgr allele, which may be attributed to environmental influences or the interaction between variety and fragrance, as noted in previous studies (Itani et al., 2004; Gaur et al., 2016; Nguyen Thi Lang and Bui Chi Buu).

2008) In general, the results indicate that the functional marker badh2-E7 are effective to distinguish fragrant varieties in Vietnamese rice landrace varieties

Two significant deletion mutations in the Badh2 gene have been linked to fragrance in rice The first, an 8-bp deletion in exon 7, was identified by Bradbury et al (2005) Subsequently, Shi et al (2008) discovered a new allele, known as the badh2-E2 allele, which features a 7-bp deletion in exon 2 and also contributes to rice fragrance This discovery is based on the sequence divergence between functional Badh2 alleles and null alleles A functional marker for the badh2-E2 allele has been developed, allowing for easy differentiation.

The Badh2 allele was identified with a PCR product size of 207 bp, while the badh2-E2 allele was detected at 200 bp The application of this functional marker for the detection of the badh2-E2 allele in our rice collection revealed a consistent banding pattern, as illustrated in Figure 4.4 The results, summarized in Table 4.3, indicate that all samples displayed a banding pattern corresponding to the 207 bp size.

Figure 4.4 PCR banding patterns for functional marker badh2-E2

L: Ladder Low range, 1: Bac Thom 7, 2: Khang Dan 18, 3-10: Several representatives of the rice collection

In this experiment, 88 rice varieties were screened for the badh2-E2 allele, but due to equipment errors in polyacrylamide gel electrophoresis, only these varieties were successfully analyzed According to the data in Table 4.3, no badh2-E2 allele was detected among the examined varieties, which included 26 Japonica, 59 Indica, and 3 admix varieties, indicating that they are not 7-bp deletion mutated in exon 2 These findings align with Seno et al (2013), who also found no badh2-E2 allele in Indonesian rice varieties However, since the experiment was not fully completed, it is not possible to definitively conclude the presence of the badh2-E2 allele in our rice collection.

This mutation type has known as a loss-of-function of Badh2 gene in exon 2 that affects the accumulation of 2AP causing fragrance on rice (Shi et al., 2008)

The fragrance of rice grain is linked not only to the fgr allele but also to the badh2-E2 allele, as noted by Shi et al (2008) and Shao et al (2013) In a study of 27 rice genotypes, including four non-fragrant and 23 fragrant lines, Shao et al (2011) identified eight genotypes with the badh2-E2 allele, characterized by a 7-bp deletion in exon 2 Notably, all eight genotypes were Japonica rice varieties from the neighboring provinces of Jiangsu and Anhui in China.

Apart from two major mutant alleles of Badh2 gene (i.e., fgr (Bradbury et al.,

Research has identified several mutations associated with fragrance in rice Notably, Shi et al (2008) reported the badh2-E2 mutation, while Shao et al (2011) discovered a new 803-bp deletion between exons 4 and 5 that influences the fragrant trait This deletion can be amplified using the functional marker FMbadh2-E4-5, yielding PCR products of 321 bp.

The study utilized the FMbadh2-E4-5 marker to genotype the fragrant alleles in a rice collection, revealing a 35 bp difference from the badh2-E4-5 allele and a 1123 bp difference from the wild-type Badh2 allele The results, which encompass the entire rice collection analyzed, are detailed in Table 4.3.

Figure 4.5 PCR banding patterns for functional marker FMbadh2-E4-5

L: Ladder 1kb, “+”: G154, “-”: Khang Dan 18, 1-14: Several representatives of the collection

The type of badh2-E4-5 mutation was detected in 6 varieties among 182

The selection of promising high-quality fragrant local rice varieties for rice

The study identified 13 fragrant rice varieties with Badh2 mutations, specifically an 8-bp deletion in exon 7 and/or an 803-bp deletion between exons 4 and 5, including varieties G108, G132, G154, G161, G177, G178, G200, G214, G24, G25, G50, G61, and G86 Detailed information about these varieties is presented in Table 4.4 These findings indicate that these local rice landrace varieties may serve as valuable genetic resources for breeding fragrant rice or could be reintroduced into production.

Of 13 promising fragrant varieties determined, 10 have 8-bp deletion mutation in exon 7 of Badh2 gene, 4 have 803-bp deletion between exons 4 and 5, especially, one (G154) has both these mutation types (Table 4.3) G177, G178 and G25 have strong fragrance in grains, and the others are slightly fragrant These 13 promising varieties include 9 Japonica, 2 Indica, and 2 admix Nine varieties (G132, G154,

Glutinous rice varieties include G178, G200, G214, G25, G50, G61, and G86, while regular rice consists of G108, G161, G177, and G24, with G108 and G24 specifically identified as Tám rice Additionally, Japonica fragrant rice varieties primarily originate from the Northern mountainous regions, including Hoa Binh, Lai Chau, Lao Cai, and Yen Bai These findings are valuable for fragrant rice breeding programs.

Tran Manh Cuong et al (2014) identified three promising fragrant rice varieties—Hoa Sua, Seng Cu, and ST19—based on the relationship between phenotype and genotype for fragrance These varieties exhibited low amylose content Additionally, the study highlighted the correlation between sensory assessments and functional markers, along with evaluations of other physical traits, further supporting the selection of these fragrant rice varieties for breeding programs.

37 varieties (TP5-1, TP-5-3, TP5-4) were supposed to be high-quality and meet export standards (Nguyen Phuc Hao et al., 2009)

Table 4.4.List of promising varieties for rice breeding program

No ID Name of varieties Location Rice group Level of fragrance

Mutation types of Badh2 gene

1 G108 Tám ấp bẹ Ninh Binh Regular rice Slightly fragrant 8-bp deletion in exon 7

2 G132 Padai tlig jug Khanh Hoa Glutinous rice Slightly fragrant 8-bp deletion in exon 7

3 G154 Nếp thơm Ha Tay Glutinous rice Slightly fragrant 8-bp deletion in exon 7 and

803-bp deletion between exons 4 and 5

4 G161 Bn 1 An Giang Regular rice Slightly fragrant 8-bp deletion in exon 7

5 G177 Chăm hơm Hoa Binh Regular rice Fragrant 8-bp deletion in exon 7

6 G178 Kháu chính phủ Hoa Binh Glutinous rice Fragrant 8-bp deletion in exon 7

7 G200 Chà fu nu Lai Chau Glutinous rice Slightly fragrant 8-bp deletion in exon 7

8 G214 Blè blậu đơ Lao Cai Glutinous rice Slightly fragrant 8-bp deletion in exon 7

9 G24 Tám xoan hải hậu Nam Dinh Regular rice Slightly fragrant 8-bp deletion in exon 7

10 G25 Nếp vàng ong lạc sơn HB

Hoa Binh Glutinous rice Fragrant 803-bp deletion between exons 4 and 5

11 G50 Lúa nếp 3 tháng dạng 1 Quang Nam Glutinous rice Slightly fragrant 8-bp deletion in exon 7

12 G61 Nếp rằn Quang Binh Glutinous rice Slightly fragrant 803-bp deletion between exons 4 and 5

13 G86 Tan ngần Yen Bai Glutinous rice Slightly fragrant 803-bp deletion between exons 4 and 5

CONCLUSION AND PROPOSALS

Conclusion

- Among 181 local Vietnamese rice varieties evaluated by sensory method, 4 were categorized as fragrant, 14 as slightly fragrant, the rest of 163 varieties as non- fragrant

Two mutation types of the Badh2 gene, responsible for fragrance in rice, were identified in 13 fragrant varieties, including G108, G132, G154, G161, G177, G178, G200, G214, G24, G25, G50, G61, and G86 These mutations include an 8-bp deletion in exon 7 and an 803-bp deletion between exons 4 and 5 Notably, no rice varieties exhibited a 7-bp deletion mutation in exon 2 Interestingly, the two detected mutation types were found in some non-fragrant rice varieties while being absent in certain fragrant ones, highlighting the need to further investigate the genetic basis of fragrance in Vietnamese rice landrace varieties.

Thirteen promising fragrant rice varieties have been identified, featuring an 8-bp deletion mutation in exon 7 and/or an 803-bp deletion mutation between exons 4 and 5 The selected varieties include G108, G132, G154, G161, G177, G178, G200, G214, G24, G25, G50, G61, and G86 These varieties hold potential as valuable genetic resources for fragrant rice breeding programs and may be reintroduced into production.

Proposals

The LMI RICE-2 team is tasked with analyzing the badh2-E2 allele across all left varieties in the rice study collection using the functional marker badh2-E2 The final data will enable a comprehensive assessment of genetic diversity within the collection, leading to the selection of promising varieties for the breeding program.

- The determination and discovery of other mutations related to this fragrant trait in the studied rice collection also should be conducted to provide with information source for next studies

- The promising fragrant rice varieties should be used in breeding program or developed for production

Tiêu đề	The assessment of the fragrant trait in a collection of Vietnamese rice landrace varieties
Tác giả	Vu Manh An
Người hướng dẫn	Dr. Hoang Thi Giang, Dr. Nguyen Thi Lam Hai
Trường học	Vietnam National University of Agriculture
Chuyên ngành	Biotechnology
Thể loại	graduation project
Năm xuất bản	2021
Thành phố	Hanoi

Định dạng
Số trang	62
Dung lượng	1,41 MB