نوع مقاله : علمی پژوهشی - اصلاح و بیوتکنولوژی
عنوان مقاله English
نویسندگان English
Introduction
Rice grain quality includes appearance, milling, cooking and nutritional quality, which are determined by the physicochemical properties of the rice grain. Among these, amylose content (AC), gelatinization temperature (GT), gel consistency (GC) and paste viscosity properties are considered as the main and important indicators determining the cooking quality of rice. The aim of this study was to investigate the relationship between molecular markers and the characteristics determining the cooking quality of rice and to introduce informative markers associated with these characteristics.
Materials and Methods
The plant materials of this study were a diverse collection of 61 rice genotypes adapted to Iranian climatic conditions, the seeds of which were obtained from the Rice Research Institute of Iran (RRII), Rasht, Iran, and the International Rice Research Institute (IRRI), Philippines. The studied traits were the characteristics determining the cooking and eating quality including AC, GT and GC, as well as the paste viscosity parameters derived from the rapid visco analazer (RVA) including peak viscosity (PV), minimum viscosity (MV) or hot paste viscosity (HPV), final viscosity (FV) or cool paste viscosity (CPV), setback viscosity (SV), breakdown viscosity (BV), and consistency viscosity (CV). For molecular evaluation of the studied genotypes, by reviewing previous studies as well as by searching the Gramene website (www.gramene.org), 40 molecular markers associated with rice cooking quality characteristics, including 38 microsatellite markers, a specific marker for the Waxy gene, and a STS marker W2R, were selected. Genomic DNA was extracted from young leaf samples using the CTAB method and the quality and quantity of DNA was determined using 1% agarose gel. Polymerase chain reaction (PCR) was performed using a thermocycler GenAmp, USA, in a 10 μL volume including 8 μL of the PCR master solution (PCR Buffer 10X, dNTPs 5 mM, MgCl2 50 mM, Tag DNA Polymerase 5U/µL) and 2 μL of genomic DNA sample with a concentration of 10 ng/µL. PCR products were separated using 10% polyacrylamide gels and the gels were stained with ethidium bromide. For data analysis, banding patterns in each genotype were scored based on presence (one) or absence (zero) and stepwise regression was used to identify significant markers associated with each of the studied traits.
Results and Discussion
The results of this study showed that genes located at the Waxy and Alk loci in chromosome 6 of rice played an important role in controlling most of the characteristics determining cooking and eating quality, including AC, GT, GC and paste viscosity parameters from RVA profile. Among the 40 molecular markers studied, seven markers RM190, RM253, RM510, RM584, RM3183, RM5371 and W2R, in addition to controlling a greater share of trait variation, showed a significant association with several traits. This result could be due to the quantitative and pleiotropic effects of similar genes or strong linkage between different genes located at the position of these markers in controlling the relevant traits. Among them, marker RM190 had significant associations with five traits (AC, GT, PV, MV and FV), marker RM5371 with four traits (AC, PV, FV and CV), markers RM253 (GT, FV and CV) and RM510 (GC, PV and MV) with three traits, and markers RM584 (PV and MV), RM3183 (MV and SV) and W2R (GC and PV) with two traits, and were identified as more important linked markers with rice cooking and eating quality.
Coclusion
The results of this study showed that the Waxy and Alk gene loci played an important role in controlling rice cooking and eating quality traits. Out of 40 markers evaluated in this experiment, seven markers RM190, RM253, RM510, RM584, RM3183, RM5371 and W2R had significant associations with rice cooking and eating quality traits. Therefore, if the results are confirmed by repeating the experiment, these markers can be proposed as informative markers for use in marker-assisted selection (MAS) programs.
کلیدواژهها English
