Sarika Mathure

Comparative quantitative analysis of headspace volatiles and their association with BADH2 marker in non-basmati scented, basmati and non-scented rice (Oryza sativa L.) cultivars of India

For the first time, 91 Indian rice (Oryza sativa L.) cultivars, belonging to non-basmati scented (77), basmati (9) and non-scented (5) categories, were quantitatively analysed for 23 headspace volatiles. In addition, the BADH2 marker related to 2-acetyl-1-pyrroline (2AP) synthesis is validated among the cultivars representing these categories. The non-basmati scented cultivars (15) excelled in 2-acetyl-1-pyrroline (2AP) content compared to basmati cultivars. The major aroma volatile (2AP) correlated positively with 1-tetradecene and indole, and negatively with benzyl alcohol. On the basis of nonanal, octanal, decanal and 1-octen-3-ol contents, basmati cultivars were different from non-scented cultivars. Benzyl alcohol, 2-phenylethanol, 2-amino acetophenone, indole, 1-hexanol and nonanoic acid exhibited significant variation among rice categories under study. This study reports 16 non-basmati scented cultivars with variations in the BADH2 locus rendering a marker based on 8bp deletion in BADH2 as unsuitable for MAS in rice cultivars under study.

Characterisation of aromatic rice (Oryza sativa L.) germplasm and correlation between their agronomic and quality traits

Eighty-eight aromatic cultivars collected from Maharashtra state were assessed for determinants of kernel quality (kernel size-shape, test weight and aroma) and grain morphology such as awning, lemma and palea characters, pubescence, colour of sterile lemma and apiculus colour. We, report seven cultivars—‘Girga’, ‘Kothmirsal’, ‘Kala bhat’, ‘Chimansal’, ‘Jiri’, ‘Kalsal’ ‘Velchi’ and ‘Kali kumud’ as indigenous to southern India. Of the 69 cultivars characterized for agronomic traits 36 cultivars were exquisite genotypes and possessed one or more superior traits such as early flowering, dwarf stature, higher number of productive tiller per plant; long panicles; higher number of filled grains per panicle and strong aroma. Variability in aromatic cultivars was assessed on the basis of nine traits placed aromatic rice cultivars in five clusters. Number of cultivars in each cluster ranged from 1 to 33. 27 significant correlations were obtained in the physical, agronomic and grain morphology traits. Aroma was found to be negatively associated with days to 50% flowering as well as with filled grains per panicle. However, correlation between panicle length and effective tillers with aroma was not observed. Therefore, to increase the yield, improvement in length of panicle and increasing number of productive tillers in medium or mild scented cultivars would be the best strategy.

Diversity analysis in selected non-basmati scented rice collection.

Diversity analysis among 23 rice varieties including 16 non-basmati scented accessions, 5 basmati accessions and 2 non-scented accessions was performed by random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) marker systems. The varieties analyzed by 11 RAPD and 8 ISSR primers yielded an average of 65% and 80% polymorphism, respectively. The average number of polymorphic bands generated per RAPD primer was 6 and per ISSR primer was 5.87. RAPD and ISSR data analysis individually could not segregate basmati and non-basmati scented rice accessions. However, the analysis using a combined data could group basmati and non-basmati scented rice accessions separately. The bands present specifically among three accessions of non-basmati scented rice were also identified. The study revealed a high genetic diversity among non-basmati scented rice accessions.

Determination of some minerals and β-carotene contents in aromatic indica rice (Oryza sativa L.) germplasm

39 aromatic indica rice (Oryza sativa L.) cultivars were characterized for Iron, Zinc, Calcium, Magnesium, Copper and β-carotene contents. The β-carotene contents were ranging from 1.23 to 9.9μg/g in brown and 0.08 to 1.99μg/g in milled rice. Among the mineral contents, Magnesium was found ranging from 855μg/g (Gham) to maximum of 1636μg/g (Badshahbhog) followed by Iron in 32μg/g (Jirga) to 218μg/g (Kalsal), Copper content from 2μg/g (Girga) to 1004μg/g (Gham), Zinc content from 25 (Gham) to 165μg/g (Ambemohar-157) and Calcium ranged from 14μg/g (Ambemohar pandhara) to 67μg/g (Kate chinoor). The study showed that the germplasm assessed is a good source of micronutrients and can be further exploited in breeding programme.

Collection of Germplasm of Scented Rice Cultivars and Grain Morphological Assessment

Ancient India is one of the oldest regions where cultivation of O. sativa L. began. The foothill of the Himalayas is the center of diversity of scented rice of Group V; from here by westward route scented rice cultivars are distributed in Rajasthan, Madhya Pradesh, Maharashtra, and Gujarat (Glaszmann 1987). In these states, numerous scented varieties belonging to this group are grown under different names (Khush 2000, Table 2.1). It is estimated that India has over 70,000 cultivars of rice germplasm and has a sizable number of wild forms still to be collected and conserved (Siddiq 1992). Since the time of civilization, thousands of locally adapted scented rice genotypes have evolved as a consequence of natural and human selection. These landraces are the genetic reservoirs of useful genes. The collection and evaluation of landraces are a part of the fundamental work of rice geneticists for breeding purposes. Considering the need for broadening the gene pool of rice, it is necessary to collect and conserve the cultivars that are locally cultivated and maintained by farmers.

Quality Parameter Assessment in Scented Rice Cultivars

Rice quality is a complex trait comprising many physicochemical characteristics. Consumers base their concept of quality on the grain’s appearance, size and shape of the grain, behavior upon cooking, taste, tenderness, and flavor of cooked rice (Table 3.1). Appearance of milled rice is important to consumers. Thus, grain size and shape are the first criteria for rice quality that breeders consider in developing new varieties (Adair et al. 1966). Preferences for grain size and shape vary with consumers as some ethnic groups prefer short bold grains, while medium and long slender grains are preferred by others. The cooking and eating qualities of rice are valuable properties, especially in Asia, where it is the most important food. These qualities are largely determined by the properties of starch that makes up to 90 % of milled rice. Gelatinization temperature, amylose content, and gel consistency are the important starch properties, which influence cooking and eating characteristics. Gelatinization temperature determines cooking time of rice. Amylose content correlates negatively with taste panel scores for cohesiveness, tenderness, color, and gloss of rice and hence predicts the cooking and processing behavior of rice (Juliano 1979). The texture of rice varies on the basis of gel consistency in high amylose content rice. In general, rice with soft to medium gel consistency, intermediate amylose content, and intermediate gelatinization temperature is a preferred level for the consumers (Khush et al. 1979). However, the cooking quality preferences are known to vary within the country, within the ethnic groups, from one country to another, and within different geographical regions (Juliano et al. 1964). Extra elongation on cooking is a highly desirable trait in high-quality rice like basmati (Table 3.2, Fig. 3.1). Thus, these parameters play a crucial role in rice quality.

Molecular Marker-Based Assessment of Genetic Diversity and Quality Trait Specific Marker Validation

India is considered as one of the centers of origin of rice (Oryza sativa L. ssp. indica) and a center of its diversity (Rana 1995). Archeological excavations have shown that rice has been a part of the food economy of early man in China and India from around 5000 BC (Sharma et al. 2000). Thousands of years of evolution because of adaptation to varied agroclimatic conditions and selection by farmers based on diverse quality preferences have resulted in accumulation of rich genetic diversity in rice. Singh and Singh (2003) reported that India has the world’s largest germplasm of scented rice varieties. Among scented rice, basmati rice is a unique varietal group which has distinguished itself in consequence of natural and human selection. The uniqueness of basmati rice is determined by extra long slender grain, higher elongation on cooking, soft and fluffy texture of cooked rice, and pleasant aroma. Besides the genetic makeup, the qualities of basmati rice are expressed when it is grown in the northwestern foothills of Himalayas under unique combination of growing conditions such as soil, water, climate, and cultural practices (Siddiq et al. 2012).

Aroma Volatile Characterization in Indian Scented Rice (Oryza sativa L.) Cultivars

Flavor volatiles or aroma and texture are the principle sensory qualities of rice and have been rated as the major criteria for preference. Consumer’s appreciation and the wide popularity of scented rice augmented its demand in domestic as well as in international markets. India holds the highest biodiversity of scented rice and has a huge number of basmati and nonbasmati rice varieties. Besides basmati type, some nonbasmati types – viz., Kalanamak, Sakerchini, and Hansraj grown in eastern Uttar Pradesh; Dubraj, Chinoor grown in Chhattisgarh; Kalajoha grown in northeastern states; Randhunipagal grown in Orissa; and Ambemohar grown in Maharashtra – are popularly cultivated and exported.