Sensory Test and Molecular Marker Based-Selection for Aromatic Rice in the F3 Progenies

Abstract

Aromatic rice is a special type of rice that highly preferred by people in Asia due to the presence of aroma. Aroma in rice is determined by 2-acetyl-1-pyrroline (2AP) compound which is controlled by a recessive fgr gene. A hybridization between cv. Sintanur (aromatic rice) and PTB33 (non-aromatic, resistant to brown planthopper/BPH) has been done in order to develop aromatic rice lines that resistant to BPH. In the F2 progeny, molecular marker-based selection and bioassay for the brown planthopper resistant lines have been carried out; however selection for the aromatic trait has not been performed yet. The objective of this study was to obtain the F3 progeny’s individual with aromatic trait. Sensory test was conducted by KOH 1.7% solution, meanwhile molecular markers applied were ESP (External Antisense Primer), IFAP (Internal Fragrant Antisense Primer), INSP (Internal Non fragrant Sense Primer) and EAP (External Antisense Primer). Eighty-eight plants from two selected (SP#31 and SP#224) F3 lines progenies derived from cv. Sintanur and PTB33 have been evaluated in this study. Detection by molecular markers found seventy-five genotypes (85.23%) were homozygous recessive (aromatic rice) and one was heterozygous (non-aromatic). Eighty-five (96.59%) genotypes were aromatic as detected by sensory test alone. Seventy-two (81.82%) genotypes were categorized as aromatic rice based on sensory test and molecular markers. Due to inconsistency results from each method alone, it is advised both methods to be applied to ensure the reliability and the accuracy since aroma in rice is affected by genetic composition and environment conditions. Selected genotypes will be continued for breeding program in developing aromatic rice with improved agronomic traits.

Evaluation of Aroma in Malaysian Rice Landraces Through Sensory Test and Molecular Approach

“…Five rice landraces, namely Pulut Bukit, Silou, Jangrai, Kantan Merah, and Mepawan, were shown to have a slight aroma in a sensory test but were not detected using molecular markers. Carsono et al (2020) and Yeap et al (2013) also discovered undetectable aromas using molecular markers in their respective studies. Buttery et al (1983), reported that 2acetyl-1-pyrroline, or 2-AP, a volatile compound with a popcorn-like aroma, is the only component that has been identified as a significant contributor to the pleasant scent of aromatic rice and the only compound shown to quantify rice's aroma (Hu et al, 2020).…”

“…On the other hand, Tutumoh, Beruang, Telinga, and Apit were scored as non-aromatic based on the sensory test but were identified as aromatic based on molecular markers. According to Carsono et al (2020), the extremely low concentration of 2-AP in the genotypes may result in aromas being undetected by panellists in sensory testing. Meanwhile, Alrufaye et al (2018) suggested that it could be because of the allegations of minor genes that regulate rice aroma.…”

“…Moreover, rather than being influenced by subjective factors such as emotion, physical condition, and environment, sensory evaluation was considered to be highly subjective and not quantitative (Hu et al, 2020). Nevertheless, this method remains recognized as a practical and acceptable technique for detecting the aroma of rice, despite the fact that the presence of this 2-AP compound is often detected through sensory tests (Carsono et al, 2020;Hien et al, 2006). In addition, previous research has shown that the aromatic character of rice as measured by sensory tests correlates significantly with the 2-AP concentration (Ishitani and Fushimi, 1994).…”

“…According to Alrufaye et al (2018), the determination of aroma cannot rely solely on sensory testing but must be complemented by other techniques. In addition to Carsono et al (2020), the results from the two methods are more reliable and accurate compared to a single method because the aroma of rice is highly influenced by genetic composition and environmental conditions. Combining several approaches to detect aroma in rice has been a common practice for decades, such as gas chromatography with molecular marker mapping (Lorieux et al, 1996); Allele Specific Amplification (External Antisense Primer, External Sense Primer, Internal Nonfragrant Sense Primer, and Internal Fragrant Antisense Primer) with sensory evaluation on leaves and grains (Yeap et al, 2013); molecular markers using ESP (External Antisense Primer), IFAP (Internal Fragrant Antisense Primer), INSP (Internal Non fragrant Sense Primer) and EAP (External Antisense Primer) with Sensory test using KOH 1.7% solution (Carsono et al, 2020).…”