| Hybrid necrosis in hexaploid triticale by R.K. BEHL and N. MAHERCHANDANI Department of Genetics Haryana Agricultural University, Hissar (India) Hybrid necrosis is a physiological disorder which leads to morphological abnormalities or seedling lethality, depending upon the strength and expressivity of necrotic genes in the parents. The effects of necrotic genes and their alleles present in Triticum aestivum., L., have been well documented (HERMSEN 1963; GILL et al. 1972; ZEVEN 1975) but little is known about distribution of these genes in durum wheat and triticale. Survey of durum selections at CIMMYT (Mexico) indicated the presence of Ne1 allele in twenty strains. This allele was found in some triticale lines also. Present study deals with six inter-varietal combinations where one or the other abnormality was recorded. Materials and Methods Six F1's along with their parents were evaluated for germination and seedling growth in vitro. Visual observations for plant growth were also recorded in field conditions. One year old seeds stored at room temperature were soaked in 10 ppm solution of Gibberellic acid (GA3) for four hours and placed in petri plates lined with filter paper soaked in 10 ppm GA3 solution. These plates were then kept in incubator at 25C. In the second set cold treatment was given. Seeds were soaked in distilled water for four hours and then placed in petri plates lined with wet filter paper for 48 hours at 4C. These petri plates were then transferred to the incubator in which the temperature was 25C. The third set was kept as control ie soaking of seeds in distilled water for four hours then transferring petri plates to incubator (25C). Germination was recorded at 3rd and 7th days after sowing. Results and Discussion Experimental results revealed that in control set (table 1) most of the parents showed fairly high germination on 3rd day and slight increase in germination was recorded on 7th day, whereas hybrids invariably recorded no germination or very poor germination with reduced seedling vigour. To test whether non-germination of F1 seeds was due to dormancy or hybrid necrosis, gibberellic acid and cold treatments were tried as they are known to break dormancy (NAYLOR & SIMPSON 1961). Since the germination of parental genotypes was satisfactory, gibberellic acid treatment was only applied to F1 seeds. |
| Present Address: Institute of Agronomy and Plant Breeding Gottingen, West Germany. |
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