Mapping gene(s) for grain quality in rice (Oryza sativa L.) using RAPD and RFLP markers

Date

3-1995

Abstract

In an attempt to explore the possibilities of mapping genes for aroma and gelatinization temperature in rice, RAPD markers were identified using bulked segregant analysis on F2 and F3 families and confirmed with RFLP markers.

The genetic study of Basmati 370 and IR36 revealed that the aroma in Basmati 370 may be under the control of a major recessive gene, since F1 is non aromatic and F2 segregated into 1=aromatic to 3=aromatic. Analysis on the basis of the four categories, namely : non, slightly, moderately, and strongly aromatic showed that aroma is under the control of few genes.

DNA from Basmati 370, IR36, bulk of aromatic homozygotes, and bulk of nonaromatic homozygotes were analysed with random primers using Polymerase Chain Reaction (PCR). Out of 550 primers, two primers viz., AG8 and AN1 generated polymorphism between aromatic and nonaromatic types. The cosegregation of putative markers that here after named AG8-AR, AN1-AR1 and AN1-AR2 was observed based on 44 F2 individual plants. AG8-AR,AN1-AR1 and AN1-AR2 are linked to the gene with linkage distances of 6.9, 8.9 and 16.4 cm respectively.

The AG8-AR RAPD marker was isolated and used as a probe yo survey the polymorphism between Basmati 370, IR36 and Azucena, 1R64 (parents of mapping population). AG8-AR showed polymorphism when the genomic DNA of Basmati 370, IR36, Azucena, and IR64 were digested with Taql. The association of aroma with AG8-AR was confirmed by hybridization with F2 population, x2 =181.51, (P=0.01). The location of AG8-AR (RAPH marker) was determined on chromosome 8 linked with two markers viz. , RZ617 and RG978 with 2.1 and 1.7cm cm respectively using MAPMARKER software. Mapping was done using a basic map population, 135 double haploid lines (DHLs) which generated from Azucena and IR64 via anther culture. The RAPD markers (AN1-AR1 and (AN1-AR2) from AN1 primer did not show polymorphism between Basmati 370,1R36 and Azucena IR64 with nineteen restriction enzymes namely, EcoR1, EcoRv, ScaI, XhoI, DraI, APaI, XbaI, BamHI, HindIII, AluI, TaqI, BgIII, Rsa1, HaeIII, MsPI, BSTE, Sma1, AatI, and MvaI.

In mapping the genes for gelatinization temperature (GT), the parents involved were IR2071-137-5, with high GT, IR24 and IR43 with low GT. Based on primary survey (using 30 RFLP clones and 40 RAPD primers), the IR2071-137-5 and IR24 was selected as the parents of GT trait, because these two parents indicated more polymorphism compared to IR2071-137-5 and IR43. Out of 588 F2 seeds 483 showed high GT, 43 intermediate and 62 low GT which fit to the 3:1 ratio for high Gt to low GT. Out of 1393 seeds from F3 family, 777 indicated high GT, 100 intermediate, and 516 low GT. Out of 125 F2 plants, 38 homozygous high GT, 23 homozygous low GT, and 64 heterozygouts were recognized.

Alkali spreading of F2 seeds revealed that the GT is under the control of single dominant gene. Bulk sgregant analysis (BSA) strategy was followed to identify putative markers for GT. A total of 450 random primers were screened between bulks of high GT and low GT along with their parents. Two primers, viz. , AL15 and AF17, generated polymorphism between high GT and low GT types. The analysis of consegregation of RAPD markers with GT gene and their mapping are in progress.

Document Type

Dissertation

Degree

Doctor of Philosophy in Genetics

College

Graduate School (GS)

Adviser/Committee Chair

Rita P. Laude

Co-adviser

Gurdev S. Khush

Committee Member

Adelina A. Barrion, Nigh Huang, Dario C. Sabularse

Language

English

LC Subject

Rice--Genetics

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 996 1995 G2 N45

Notes

Doctor of Philosophy (Genetics)

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