| MAAN & LUCKEN (1968) indicated that certain common wheat cultivars have
genes for partial male fertility restoration, whose action is expressed
under certain favourable environments. MIRI et al. (1970) reported
that NP 839 and NP 883 restored fertility in male sterile lines of Kalyansona,
NP 880 and Lerma Rojo having timopheevi cytoplasm. But NP 880 and
NP839 did not restore fertility in the present comosa cytoplasmic
interaction. TSUNEWAKI et al. (1976) showed Junrei Komugi and Norin
69 had weak fertility restoring gene (s) with timopheevi cytoplasm.
The differential behaviour of fertility restoration in genetically diverse
male sterile lines may be attributed to the specificity of modifiers and
of partial or full fertility restoration factors in normal cultivars. This
led to the assumption that stability of male sterility and the restoration
of male fertility depended on genetic and environmental conditions (TSUNEWAKI
et al. 1976) Crossed seed fertility was observed in male sterile lines with a view to find seed fertility and female lethality. Results summarised in Table 1would indicate that there was no significant departure on the crossed seed set percent in all the generations thereby indicating normal female fertility. PANAYOTOV (1980) reported that the foreign cytoplasm did not show any harmful influence on crossability. Seed set under natural cross pollination in the present study revealed that the highest seed set was 68% in BC2 allo-Kharchia followed by 65% in BC1 allo-Mukta and in F1 allo- Kharchia showed 34%. The substantial variations in seed set between the generations and different male sterile lines can be attributed to many factors which include nonsynchronous flowering, stigma respectively, pollen availability and environmental changes (IMRIE 1966 ; KIHARA 1967). As cross pollination in a highly self pollinated crop like wheat is of great hinderance in economic exploitation of hybrid wheat due to its closed floral nature, future breeding strategy should be towards modification of floral structure and selection of good pollinators having flower synchrony. References IMRIE, B.C. 1966. Australian J. Expt. Agrio Animal Husbandry 6 : 175-178. KARIM, M.A. 1982. Ph. D. Thesis, IARI, New Delhi-12, India. KIHARA, H. 1967. Dur Zucher 37 (2) : 86-93. MANN, S.S. and LUCKEI, K.H. 1968. Proc. III Int. Wheat Genet. Symp. (Canberra) : 135-140. MIRI, R.K., AMAWATE, J.S. and JAIN, H.K. 1970. Wheat Inf. Serv. 31 : 9-11. PANAYOTOV, I. 1980. Theor. Appl. Genet. 56 (4) : 153-160. TSUNEWAKI, K. 1974. Jap. J. Genet. 49 : 425-433. TSUNEWAKI, K., NAKAI, Y. and FUJIGAKI, 1976. Jap. J. Breed. 26 (1) : 25-31. TSUNEWAKI, K. 1980. Seiken Ziho 29 : 40-56. WILSON, J.A. and Ross, W.M. 1962. Crop Sci. 2 : 415-417. |
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