| Hybrid necrosis in wheat R.K. CHOWDHURY Haryana Agricultural University, Regional Research Station, Bawal - 123501 (M/Garh), India. Hybrid necrosis in wheat is one of the major barrier encountered by plant breeders in bringing together desirable genes of different cultivars. Some of the Indian varieties like C 306, X 286, C 273 and NP 890 have been reported to give complete or partial necrosis in crosses with the genes present in Mexican germplasm (NARULA et al. 1966; GILL et al. 1969, 1972; ANAND et al 1969). Much work on this aspect has been reported by HERMSEN (1963), and ZEVEN (1965, 1976). Based on these studies, it has been suggested that two complementary genes Ne1 and Ne2 When brought together causes necrosis in wheat, the degree of necrosis in the F1 plants varying considerably due to multiple allelism (s, m and w) of Ne1 and Ne2. The present investigation adds further information in this direction which will be of interest to wheat breeders. Buring the year 1979-80, with a view to transfer drought/rust resistance, a crossing programme was initiated at this centre, in which four standard wheat varieties namely; C 306, WH 147, Kalyansona and Sonalika were crossed with a number of varieties having drought/rust resistance in a line x tester analysis. Variety C 306 is tall growing, possesses bold amber grains and is a best available variety for rainfed conditions. Sonalika is a single dwarf and recommended for late sown conditions, while WH 147 and Kalayansona are double dwarf and recommended for normal sown high fertility conditions. During the following year, all the s were grown in the field. Among these crosses, seedlings of nine crosses (Table 1) were very weak from the initial stage. They started yellowing at 2-3 leaf stage and finally died at 4-6 leaf stage without producing any ear showing the characterstic symptoms of severe necrosis of grade 7 as described by HERMSEN (1963). The different morphological characteristics of the seedlings in different F1 hybrids have been given in Table 1. As it has been reported that variety C 306 carries strong allele(s) of Ne1 gene (GILL et al. 1969, 1972; ANAND et al. 1969), therefore, rest of the varieties (MP 823A, Raj. 939, HD 2278, K 7526, HD 2037, P 48-B, P 118-1, Ageti Kalyan and E 8682) are supposed to be the carrier of Ne2 gene, thereby giving severe necrosis. The present findings support the report of ZEVEN (1966) on geographical distribution of Ne1 gene. He had proposed that varieties from India are carrier of Ne1 gene while the Mexican germ plasm carries Ne2 gene. Based on the observations made from these crosses, varieties possessing/not-possessing Ne1 or Ne2 gene have been listed in Table 2. These informations will be of importance to breeders/geneticists. References ANAND, S.C., GILL, B.S. & R.P. JAIN 1969. Necrosis in intervarietal crosses of wheat. Indian J. Genet., 29(1): 131-134. GILL, K.S., D.R. VASUDEVA, B.S. GHAI & M.L. GUPTA 1969. Necrosis in hybrids of Punjab variety of 306 and Mexican varieties of wheat. P.A.U.J. Res., 6: 10-13. GILL, KHEM SINGH, GHAI BACHITAR SINGH & GUPTA, MADAN LAL, 1972. Genetic and developmental analysis of hybrid necrosis in wheat. Indian J. Genet., 32: 12-17. HERMSEN, J.G. Th. 1963. Hybrid necrosis as a problem for wheat breeder. Euphytica, 12: 1-16. NARULA, P.N., S. SINGH & P.S.L. SRIVASTAVA 1966. Hybrid necrosis in bread wheat. Curr. Sci., 35: 547-548. ZEVEN, A.C. 1965. First supplementary list of genotypes of hybrid necrosis in wheat varieties. Euphytica, 14: 239-243. ZEVEN, A.C. 1966. Geographical distribution of genes causing hybrid necrosis in wheat. Euphytica, 15: 281-284. ZEVEN, A.C. 1976. Seventh supplementary list of wheat varieties classified according to their genotype for hybrid necrosis and geographical distribution of Ne-genes. Euphytica, 25: 255-276. |