Gene action in the inheritance of date to ear emergence and time to physiological maturity in bread wheat crosses (Triticum aestivum L.)

N. Tsenov1*, T. Gubatov1, E. Tsenova2

Abstract. The date of ear emergence (DEE) and the date (time) of physiological maturity (TPM), as quantitative indication affect yield and in this respect any information about their genetic nature is important for breeding in climatic anomalies of the country. This study aims to give a detailed analysis of the succession of traits DEE and TPM to gather updated information on the genetic control of contrast by combining traits varieties. We studied six generations originating from 6 hybrid combinations of “early ” and “late ” with respect to the varieties of both traits. It was determine the type of inheritance and coefficients of heritability. To identify real opportunities for breeding of early forms recurrent combinations with each of the parental varieties are made. Data suggest complex interactions between genes for both traits .An inspection for the presence of epistas by applying the well-known 3-parameter test, is calculated. For additional information components of genetic diversity were calculated. In crosses in which is found non-allelic interaction is applied 6 – parameter model, that explains the specific nature of these interactions on a cross. The combination of varieties with different dates of ear emergence and maturation succession of both traits is partially dominant to the complete domination of the “late” parent. Performing backcross procedure changes significantly in direct proportion to recurrent that in late varieties causes heterosis . At 2 /3 of the combinations studied non-allelic interaction are set at both traits. On the inheritance of every trait share a non-allelic interactions between genes that are specific for each cross and defy generalization. The direction of the inheritance to the later date suggests that the breeding of the early forms is preferable by making recurrent crosses . Earlier of ear emergence date varieties as Enola, Galatea and Obrii should be used in terms of a compromise combination of early ear heading and extending ripening of grain , which is important for obtaining a high yield of grain.

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Heritability of osmoregulation ability at durum wheat

V. Bozhanova, D. Dechev

The osmoregulation is one of the most important cell adaptation mechanisms occurred at beginning of drought. The inheritance of osmoregulation ability in durum wheat by using indirect method for trait measuring was studied. Five durum wheat genotypes with different level of tolerance to osmotic stress were included in diallel crossing scheme. Among the parents genotypes the old Bulgarian cultivar A-223 distinguishes with the lowest seedlings growth depression coeficient of 32,5 %, i.e. with best ability of osmotic regulation. The lowest osmotic regulation ability shows cultivar Gergana. The hybrid combinations including the most tolerant parent A-223 show the lowest coeficient of depression among the F hybrids. The conducted dialel analyses shows 1 the high significance of the effects of the general (GCA) and specific combinative ability (SCA) during the all 3 years of the investigation. The inheritance of high levels of osmoregulation is determinted by both the aditive and non-aditive gene effects. The non-aditive gene efects (SCA) strongly predominate over the aditive and have a significant role in the observed big heterozis effect. The significance of variances of both GCA and SCA requires the selection of single plants by investigated traits to be shifted in the later segregating progenies.

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