Heterosis studies for yield & yield traits in rice (Oryza Sativa L.) under rainfed condition

Recognising the potential of hybrid rice to increase the productivity, the present investigation was conducted using three WA CMS lines (Pusa 6A, IR79156A and IR 68897A) and 31 male genotypes. The results manifested that the magnitude of heterosis for grain yield over better parent was significantly superior in eight hybrids with highest value of 60.83% in Pusa 6A x HUR-105. Sixteen hybrids showed significant positive heterosis over standard variety (NDR-97) with highest value of 116.48% in Pusa 6A x HUR-105. Twelve hybrids showed significant positive heterosis over standard hybrid (Arize-6444) with highest value of 85.69% in Pusa 6A x HUR-105. The top two high yielding heterotic crosses over the standard variety (NDR-97) were Pusa-6A x HUR-105 (116.48%) and Pusa-6A x Pantdhan-12 (114.74%). These two hybrids also exhibited significant positive heterosis for yield over standard hybrid (Arize 6444 Gold) i.e. 85.69% and 84.19% respectively. Hybrids Pusa-6A x HUR-105 and Pusa-6A x Pantdhan-12 showed significant positive standard heterosis for almost all the desirable yield attributing traits, apart from this Pusa-6A x Pantdhan-12 also showed significant negative standard heterosis over SH (Arize-6444) for days to 1^st flowering, days to 50% flowering and days to maturity. The top heterotic crosses viz., Pusa-6A x HUR-105, Pusa-6A x Pantdhan-12, Pusa-6A x URG-30, IR-79156A x Akshaydhan and Pusa-6A x NDR-359 and others which expressed higher standard heterosis for grain yield along with other desirable yield components should be tested in large scale under rainfed condition.

Hybrids, Pusa 6A × HUR-105 and Pusa 6A × Pantdhan-12 exhibited significant heterobeltiosis for yield and yield component traits.

Hybrids, Pusa 6A × URG-30 and Pusa 6A × IET-22202 are short in their duration which is best suitable for rainfed condition. So, these hybrids may further be tested on large scale under rainfed conditions.

IR 79156A × Akshaydhan may also be promoted in rainfed areas for large scale testing as these hybrids are much better than the standard checks NDR-97 and Arize-6444 Gold.