| Leaf characters of the mutants were correlated with grain yield. Results
in Table 4 reveal that first flag leaf length
displayed significant negative correlation (-.2913) with grain yield whereas
it showed strong positive association (P>=0.01) with next flag leaf length
and weaker association with next flag leaf width. First flag leaf width
also revealed highly significant (P>=0.01) association with next flag leaf
length and next flag leaf width. SIDDIQUI (1978) and TANNER et al.
(1966) also obtained similar results. They reported the selection of high
yielding mutants on the basis of leaf characters. Leaf characters are important parameters in determining dry matter production of a plant community and affect biochemical activities such as nitrate assimilation and synthesis of nucleic acid and protein (LOOMIS and WILLIAM, 1972). Leaf area was found to be the trait that could account for higher yielding ability of mutant strains. By developing a larger leaf blade area and delaying senescence, the cultivar had the potential to produce more photosynthate than control. Leaf blade area before anthesis could affect grain yield indirectly (THORNE, 1966) through influences the number and potential size of the sites (seeds) at which the photosynthate could accumulate. Leaf blade area of mutant strains in present study was reasonably larger than those of the control before anthesis to have given the mutant strains an advantage in the size of spike (No.of spikelets/Spike) and ultimately contributed towards higher harvest index. Literature Cited BELL G.D.H. and E.J.M. KIRBY 1966. Utilization of growth responses in breeding new varieties of cereals. In "The growth of cereal and grasses". Buttenworths, London p. 308-319. DEWIT C.T. 1965. Agri. Res. Rep. 663 Cent. Agri. Publ. Doc. Wageningen p. 57 DONALD C.M. 1962. In search of yield. J. Austral. Inst. Agri. Sci. 28: 171-178. DONALD C.M. 1968. The breeding of crop ideotypes. Euphytica 17: 385-403. DUNCAN W.G., R.S. LOOMIS, W.A. WILLIAM and R. HANAN 1967. A model for simulating photosynthesis in plant communities. Hilgardia 35: 181-205. LARIK A.S. 1977. Effect of gamma rays on some wheat characters. Wheat Inform. Serv. 44: 23-25. LARIK A.S. 1978a. An evaluation of wheat mutant for useful agronomic characters. Genet. Agr. 32: 237-244. LARIK A.S. 1978b. Performance and selection of wheat mutants for some quantitative characters. Wheat Inform. Serv. 47, 48: 59-62. SCARASCIA-MUGNOZZA G.T. 1970. In manual on mutation breeding, IAEA, Vienna p. 155. SIDDIQUI K.A. and H. DOLL 1972. Screening for improved protein quality mutants in wheat. Z. Pflanzenzucht 70: 143-147. SIDDIQUI K.A. 1978. Variation in straw and leaf characteristics of wheat mutants. Rep. AEARC, Tandojam p. 19-50. SIDDIQUI K.A, M.A. RAJPUT, M.A. ARAIN, A. CHAFOOR ARAIN and K.A. JAFRI 1979. Wheat improvement by induced mutations. Gamma Field Symp. 18: 33-47. LOOMIS R.S. and WILLIAM W.A. 1972. "Plant conformation of yield". Induced Mutations and Plant Improvement (Proc. Meet. Buenos Aires, 1970), IAEA, Vienna, p. 13-25. TANNER J.W., C.J. GARDENER, N.C. STOSKOPH and E. REINBERGS 1966. Some observations on upright leaf type small grains. Can. J. Pl. Sci. 46 : 690. THORNE G.N. 1966. Physiological aspects of grain yield in cereals. In "The growth of cereals and grass". Butterworth, London p. 88-105. |
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