Identification of a Promising Novel Genetic Source for Rice Root-Knot Nematode Resistance through Markers Associated...

Area of Science:

• Agronomy
• Plant Breeding
• Nematology

Background:

• Direct-seeded rice (DSR) offers environmental and resource benefits but is threatened by the rice root-knot nematode (RRKN, *Meloidogyne graminicola*).
• Genetic resistance is a sustainable alternative to chemical pesticides for managing RRKN in DSR.
• The popular Basmati variety Pusa Basmati 1121 (PB1121) is susceptible, while Phule Radha (PR) shows high resistance.

Purpose of the Study:

• To investigate the genetic basis of RRKN resistance in an F_2:3 population derived from a cross between susceptible PB1121 and resistant PR.
• To identify novel genomic regions associated with RRKN resistance in the Phule Radha variety.

Main Methods:

• An F_2:3 rice population was generated from a cross between PB1121 and PR.
• The population was evaluated for RRKN resistance traits under artificial inoculation.
• Molecular markers linked to known RRKN resistance QTLs were used to genotype the population.

Main Results:

• Trait distribution in the F_2:3 population suggests control by major and minor-effect genes.
• Simple linear regression showed spurious associations between known markers and resistance traits.
• Phule Radha (PR) does not possess previously reported QTLs for RRKN resistance, indicating novel resistance mechanisms.

Conclusions:

• The Phule Radha rice variety harbors unique genomic regions conferring resistance to the rice root-knot nematode.
• These findings pave the way for breeding DSR varieties with durable RRKN resistance.
• Further research is needed to pinpoint the specific novel genes and QTLs responsible for resistance.