Genetics Division, Indian Agricultural Research Institute, New Delhi-12
*Present Address: Maharashtra Association for the Cultivation of Science, Law College Road, Poona-411 004.
Online published on 25 January, 2012.
(1) A large number of wheat varieties bred at the IARI have been used for converting into male-sterile and restorer lines. Most of them offered no difficulty in the process of conversion to male sterility. A few of them, however, carried modifiers that restore fertility to a limited extent. These varieties are NP 852-12, NP 875, NP 890 and Sonalika. NP 852-12 has modifiers of the strongest effect whereas Sonalika has modifiers of weak action. Four classes of varieties could be distinguished on the basis of their behaviour in T. timopheevi cytoplasm.
(2) The fertility restorer line (FR 1) is probably carrying two restorer genes, one of which is less effective. The frequencies of various classes of fertility has shown the dominance of the fertility restorer genes and the 13:3 ratio obtained in the F2 generation of emst Son. 64 × FR 1 could be explained on the basis of the ineffectiveness of one gene in the heterozygous condition, when the other gene is in a homozygous recessive state.
(3) The Indian varieties which showed partial fertility in crosses with the male sterile line were analysed for the allelic relationships with the restorer line. These crosses gave a good fit to the digenic ratio of 15:1 in F2. This shows that the Indian wheats carried one gene in common with the FR 1 line, but this gene is more effective than one of the genes in the FR 1, thus producing a modified segregation.
(4) The use of Indian wheat varieties for hybrid wheat production is discussed in the light of the above findings.
