Author(s): S. K. DASH, S. K. PRADHAN, A. K. MALL, 0. N. SINGH AND G. J. N. RAO

Abstract: Enhancing the yield potential of irrigated rice would be the key for meeting the global as well Indian rice requirement. There is more or less stagnant yield potential of semi-dwarf indica inbreeds observed since release of IR-8. New plant type is one of the potential approaches for raising yield ceiling in irrigated ecology. Tropical japonicas (Javanicas) are supposed to be the potential donors, for broadening genetic base, because of their heavy panicle size (with large number of spikelets) and stiff straw. 225 Tropical japonicas (TJ) and their derivatives (including few Assam Rice Collections) were screened for super plant type traits to be utilized as prospective donors. Variability study for the parameters viz., number of grains/panicle, plant height; tiller number and test weight exhibited comparatively higher phenotypic as well as genotypic coefficient of variation. The characters, test weight, plant height and days to flowering were recorded as highly heritable, whereas, specific leaf weight, culm strength and flag leaf angle as moderately high. On the basis of estimates hr and GA, the traits viz., plant height, flag leaf angle, culm strength, specific leaf weight and 100 grain weight could be regarded more amenable to selection. A suitable combination of desirable characters should have to be taken up, to do away with the bottlenecks for designing a NPT. TJ derivatives CR-2667-9-1, CN-65-5 and CR-780-1937-1 were found with lodging resistance along with moderate to high tillering (7.5-12.0). Genotypes CR-2667-11-1-2-1, CR-2688-6-7, CR-2667-8-2, TCA-282, CR-2672-13-1-1, CR-662-2211-1-1-5/7 and AC-38693-1 were recorded with heavy drooping panicle and high grain number, whereas, CR-2667-9-2-6 and CR-780-1937-1 with long panicle (34.0 cm), TCA-282 and CN-65-5 were with high tillering along with heavy panicle. Similarly, CR-2672-13-1-1, CR-662-2211-1-1-5/7 were observed with long upright thick top leaves (Avg. leaf length 46.0 cm); CN-65-5 and CR-2687-16-4-1 were found with good grain filling and were identified to be prospective donors. These could be hybridized with IR 73943-120-5-3-2, IR-1700-247-5-3-2-1, IR-72158-154-3-2-1-1-1, IR-73933-8-2-2-3 and IR-73107-45-3-2-3 or Swarna (MTU-7029) as female parent for development of NPTs with high grain yield coupled with tolerance to major diseases and pests..

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