Development of WGL‐1487 (Telangana Vari‐8), a High‐Yielding, Low‐Phosphorus‐Tolerant Rice ( Oryza sativa L.) Variety Possessing OsPSTOL1 ( Pup1 ) Through Marker‐Assisted Backcross Breeding

Abstract

ABSTRACT Phosphorus (P) deficiency remains one of the most critical factors restricting rice yield in India, with popular cultivars like MTU‐1121 particularly vulnerable to low‐P soils. To enhance P‐use efficiency while retaining the preferred grain and agronomic features of MTU‐1121, the OsPSTOL1 gene located within the Pup1 QTL was introgressed using marker‐assisted backcross breeding (MABB). Swarna (MTU‐7029), a high‐yielding variety possessing the Pup1 QTL, served as the donor parent. Foreground selection for Pup1 was conducted across F 1 , BC 1 F 1 and BC 2 F 1 generations using functional markers K20‐2 BspE1 and K46‐1. Background selection with 75 parental polymorphic SSR markers, combined with phenotype‐based selection, facilitated rapid recovery of the recurrent parent genome. A promising near‐isogenic line, WGL‐1487 [IET 28818 (RP 6317‐S35‐BC 2 F 4 ‐49‐25‐6‐21)], was identified at the BC 2 F 5 stage. WGL‐1487 was evaluated under the All India Coordinated Research Project on Rice (AICRPR) during the 2019 and 2021 wet seasons across P‐deficient and P‐sufficient environments. It consistently outperformed MTU‐1121 under low‐P conditions, demonstrating superior P‐use efficiency while maintaining comparable plant type, yield attributes and grain quality traits. The line exhibited 98.60% recurrent‐parent genome (RPG) recovery while retaining the target Pup1 locus and its medium‐slender grain type with desirable quality parameters, including 71.6% head rice recovery, 25.25% amylose content, 47‐mm gel consistency and an alkali spreading value of 7.0. Now released as Telangana Vari‐8, this variety serves as a suitable replacement for MTU‐1121 in P‐deficient ecologies. The variety has the potential to reduce phosphorus fertilizer requirements and improve productivity under phosphorus‐deficient conditions, thereby contributing to enhanced profitability for farmers.