Heterotic potential of basmati fertility restorers for grain yield and its components in rice (Oryza sativa L.)

Abstract

Basmati rice (Oryza sativa L.) which is characterized with long slender superfine grain, exquisite aroma and high volume expansion resulting from linear cooked kernel elongation with minimum breadthwise swelling is an internationally traded commodity. It's yields are as low as one third of non-basmati rice. A study was undertaken to evaluate the heterotic potential of basmati fertility restorers for grain yield and its components, phenological and morphological traits. Forty-five improved germplasm lines of aromatic and non-aromatic rices were test crossed with four cytoplasmic male sterile (CMS) lines viz., IR 5 8025 A, IR 62829A, PMS 10A and PMS 3 A of wild abortive cytosterile source to identify fertility restorers with basmati background. Eighty-four hybrids derived from 4 CMS lines and 21 restorers were evaluated in a randomised block design (RBO) for heterosis. Observations were recorded for grain yield and its components, phenological and morphological traits. Analysis of variance revealed significant differences (p less than 0.01) among hybrids for all traits. Five of the basmati restorers having fertility restoration > 80% produced hybrids with heterobeltiosis ranging from 20.64 to 150.66% and superiority over check ranging from 15.17 to 284.55%. Hybrids were superior to their parents for grain yield per plant, biological yield per plant, days to 50% flowering, number of effective tillers per plant and number of primaries per panicle indicated substantial heterosis. However, superiority of parents over hybrids for harvest index, 1000 grain weight and days to maturity revealed negative heterosis. Hybrid IR 58025A x Basmati 385 recorded the highest (56.26 g) grain yield per plant. The restorers Basmati 385 and HKR 241 were found heterotic with all four CMS lines. Based on yield performance and heterosis promising hybrids of basmati restorers identified were PMS 3A x P1031-8-5-1 (early), IR 58025A x Basmati 385, IR 62829A x Basmati 385, IR 62829A x HKR 241 (medium) and PMS 3A x HKR 241 (late). Heterosis in grain yield was due to concomitant heterosis in one or more major yield components. Hybrids exhibiting higher grain yield also combined heterosis for semi-dwarf plant type and reduced total grow1h duration. As the restorers were tall and late in maturity, to develop semi-dwarf, high yielding basmati hybrids fitting into multiple cropping system it is suggested to use stiff stem dwarf and early maturing basmati CMS lines as and when available.