Induction of Photoperiod- sensitive Genic Male Sterile (PGMS) mutants of rice (Oryza sativa L.)

Majid Sattari

Date

11-2000

Abstract

This study was conducted to induce variation and to develop PGMS. Induction of variation in rice varieties was done using EMS and gamma rays radiation. Based on the frequency of chlorophyll mutation, viable mutants, and seedling height reduction, variation was efficiently induced by EMS than gamma radiation, however, this dose not mean that EMS is efficient than gamma rays to induce variation in developing photosensitive genic male sterility.

From M2 generation, 340 out of 3772 progeny rows were identified having a ratio of 3:1 (fertile: partial fertile) for monogenic PGMS gene. In EMS treatment, varieties Sakha 102 (16.48%) and IR64 (16.33%) showed the highest segregating frequencies but Giza 178 showed the lowest with 5.66% frequency. Under the gamma radiation treatment, Sakha 102 (16.24%) and Nemat (15.33%) showed the highest segregating frequencies and Jinmibyeo showed the lowest frequency (0.33%). Other varieties showed comparable segregating frequency. Using the pollen/spikelet fertility evaluation, six clones were identified from field and darkroom conditions. The six clones consist of Nemat (Plant no. 867-1) and IR64 (Plants no. 1834-2, 1729-1 and 1675-2) treated with EMS and Nemat (Plant no. 2491-1 and 2532-1) treated with gamma rays. These six clones were considered as probable PGMS in M2 generation. The probable PGMS clones were evaluated further under two day length regimes and the results showed that five (M3 genotype no. 1,2,3,4, and 6) out of six clones showed partial spikelet fertility. These five genotypes however were not true PGMS.

At the M3 generation, twenty plants derived from Nemat M2 clones irradiated with gamma did not show any segregation and the mutants found antherless when grown under 14 hrs day length at the darkroom and showed pollen/spikelet fertility at 12.5 hrs day length.The twenty mutants were considered PGMS and their genotype is homozygous recessive. This has been known that the two pairs of genes with epistatic effect control this genotype. Henceforth, these twenty plants were the first PGMS mutants reported that was induced via gamma ray irradiation in indica rice.

In the confirmation of genetic male sterility in the M4 generation, thirteen lines out of fifteen did not show segregation with the expected 3 fertile: 1 sterile ratio of monogenic segregation in M4. These sterile lines were derived from clone no. 2532 of Nemat, an Iranian variety treated with gamma rays. This line confirmed as genetic male sterile mutant.

Document Type

Master Thesis

College

Graduate School (GS)

Adviser/Committee Chair

Stanley Omar PB. Samonte

Committee Member

Sant Singh Virmani, Teresita H. Borromeo

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 995 2000 A42 S28

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