| Abstrakt: |
Long day low temperatures (LDLT) and Ethrel (an ethylene‐releasing compound) were combined for inducing maximal expression of long‐term stunting in line 492 of common wheat (Triticum aestivumL.) and in its F1and F2hybrids with several normal cultivars and lines (‘Chinese Spring’, ‘Barkaee’, R.N. 228, ‘Alpha’, ‘Hazera 18’, and ‘Lakhish’). The above‐mentioned treatment was found to be most effective in inducing maximum phenotypic expression of the stunting genotypes. Most F1hybrids were intermediately stunted in response to the treatment; hybrids with Barkaee or Chinese Spring had a normal phenotype. Analysis of F2segregating populations indicated a difference of one dominant or incompletely dominant gene between most cultivars and line 492. A difference of two recessive stunting genes existed between the relatively late spring cv. Chinese Spring and line 492. The degree of earliness appeared to be related to the number of stunting genes. Monosomic analysis of F2populations derived from crosses between all the monosomic lines of Chinese Spring and line 492, under the stunting inducing conditions, (i.e., LDLT with Ethrel), revealed that chromosomes 4B and 5B of 492 possessed major genes for stunting. These genes appeared to work in an additive manner, with the stronger gene on 4B. Modifiers suppressing stunting expression appeared to be located on chromosome 2A and 2B of Chinese Spring. A reduction in stunting expression was observed in the F2populations of Chinese Spring monosomics 3A ✕ 492 and 3D ✕ 492, indicating that chromosomes 3A and 3D of Chinese Spring carried weak stunting promoters. |
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