Genetic Basis of Direct Seeding Adaptability in Rice and its Breeding Strategy

Abstract

Rice is one of the most important food crops in the world. With the decrease of rural labor force and the rapid increase of labor cost, rice production is shifting from transplanting to direct seeding. Despite the multiple advantages over transplanting, high production risk still exists in direct seeding rice and the yield is not high and unstable due to lack of direct-seeding varieties. There are three crucial problems in the production of rice direct seeding, such as poor seedling establishment, severe weed infestation and being susceptible to lodging. It is urgent to develop direct-seeding varieties which have the traits of tolerance to anaerobic germination and low temperature germination, strong early vigor, herbicide resistance and lodging resistance. Many QTL or genes have been identified for the traits of anaerobic germination tolerance, low temperature germination tolerance, herbicide resistance and lodging resistance. Some genes such as OsTPP7, OsCBL10, qLTG3-1, HIS1 and SCM2 have been successfully cloned, providing important gene resources for molecular breeding. In this review, based on the traits related to direct seeding adaptability, such as anaerobic germination tolerance, low temperature germination tolerance, herbicide resistance and lodging resistance, the rice genetic basis of direct seeding adaptability and the utilization status of the key genes controlling direct seeding adaptability and related genes were summarized. It is suggested that the development of direct-seeding rice varieties need an integrated use of modern molecular breeding and conventional breeding methods to achieve rapid and efficient pyramiding of multiple genes/traits in direct-seeding varieties, with a view to guaranteeing a sustainable development of direct-seeding rice.

Keywords

• anaerobic germination
• low temperature germination
• herbicide resistance
• lodging
• direct-seeding rice