| Productive tillers make direct contribution to increase productivity per
unit area. It may be adduced from the data presented in Table
1 that induced mutation has significant effect on reduction in spike
number only when the material is treated with 1.5 Neutron. A significant
increase in genetic variance and broad sence heritability in the productive
tillers observed in the present study indicates the potential of the improvement
of this character, that one could expect to achieve through mutations. These
results are found to be in a close agreement with those reported by LARIK
(1978) and support the hypothesis suggested by ARIAN & SIDDIQUI (1976).
Florets per spike, kernels per spike and seed set are also important yield components and are considered to be a reliable measure of the yielding ability of a crop (BOROJEVIC & BOROJEVIC 1972). The frequency of induced changes in subsequent generation depends on the number of seeds which transmit them (LARIK 1978). Mean values for above three quantitatve characters were found to be significantly (p = 0.01) reduced in triticale in response to both of the radiation sources (Table 1). The shift of mean values for these qunatitative characters in the negative direction, supports the hypothesis of GAUL & AASTVEIT (1966), which suggests that the change in the mean values for the quantitative characters occurs both in positive or negative direction and is associated with reduced vitality independent of the genotype used. Radiation affects the vitality of individuals. Poor seed set is amongst other factors a manifestation of an impaired fertility, transmitted from the affliated embroyos, through organagenesis, with the ultimate dipression in seed yield per inflorescence. Mean values for seed set character observed in the present studies (Table 1) did show a significant shift towards negative direction but exhibited an increase in the genotypic variation. These results indicate that this character could be trransmitted to further generations and significant gain could possibly be achieved through selection in early generations (LARIK 1978). Practical difficulties with triticale mutation breeding might be encountered since the shift in the mean was mostly in the negative direction. However, the range indicated an enlargement of the variation in both directions from the mean. Thus, the variation observed in the M2 generation for all the characters in triticale due to the mutagenic treatments clearly shows the potential usefulness of mutation breeding for improvement of triticale. Present investigations are preliminary in nature, and more extensive studies are required before sound conclusions could be made. Further studies in this respect show that mutation breeding which has produced useful strains in barley and other crop plants (MUNTZING 1972) should be used in triticale. RAMANATHA & JOSHI (1976), have also observed induced variation in triticale and recommended mutation as a method for improvement. The producers should be aimed at increasing the genetic base that is too narrow in the existing triticales. This should lead to an acceleration of the improvement in this new crop. Literature Cited AASTVEIT, K. 1968. IAEA Research Contract No. 284/RB. BOROJEVI'C, K. & S. BOROJEVI'C. 1972. In "IAEA" Vienna : 237. BROCK, R.D. 1967. Rad. Bot. 11(5) : 181-196. GAUL,H. & AASTVEIT, K. 1966. "Contemporay Agriculture fifth Yugoslav symp. on Res. in wheat". Novi Sad 12-18 : 263-276. GHAFOOR, A.G. & K.A. SIDDIQUI, 1976. Pak. Jour. Bot. 8 : 1-7. JOPPA, L.R. 1973. Crop Sci. 13 : 743-746. KALTSIKES, P.J. 1974. Z. Pflanzenzuchitig, 71 : 264-286. LARIK, A.S. 1978. Wheat Infor. Servi., 49 : 70-73. MUNTZING, A. 1972. Biol. Zbl. 91 : 69-80. MUNTZING, A. 1979. Triticale. Results and Problems. Adv. Pl. Br. 10 : 302-306. RAMANATHA, V.R. & JOSHI, M.G. 1976. Mutation Research 36 : 85-92. SIDDIQUl, K.A. 1972. The Nuclons. 9 : 29-35. VETTEL, F. 1960. Deu. Zuchter. 30 : 313-29. |
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