Zbigniew Broda

Analysis of genetic components of winter oilseed rape (Brassica napus ssp. oleifera ) regeneration ability under in vitro culture

This paper presents the study on the genetic components of regeneration ability of winter oilseed rape (Brassica napus ssp. oleifera ) explants cultured in vitro. The general combining ability (GCA) and specific combining ability (SCA) effects and the heritability in the broad and narrow sense were determined for four traits: the efficiency of shoot regeneration from hypocotyls, the number of regenerated shoots per single hypocotyl, the efficiency of shoot regeneration from cotyledons with a petiole, and the number of regenerated shoots per a single cotyledon with a petiole. For the study, explants originating from winter oilseed rape doubled haploid (DH) lines (W15, W69, W70, W78, and W131) and their F1 hybrids were used. Conducted analysis revealed that most of GCA effects were insignificant. None of the DH lines showed positive GCA effect, while lines W15 and W131 exhibited significant negative GCA effects for three of four analyzed traits. There were no significant SCA effects for any of the F1 hybrids. Calculated values of heritability in the broad and narrow sense were very low. The results obtained in the study confirmed that quantitative traits connected with plant regeneration under in vitro conditions are characterized by high variability. Although the results have widened knowledge of the genetic determinants of regeneration ability trait, further studies and observations are still required.

Biometric characteristics of interspecific hybrids in the genus Secale

Abstract Breeding work using European rye populations has resulted in a considerable reduction of genetic variation in breeding materials of that species. Many taxa from the genus Secale may constitute a potential source of genetic variation in rye breeding. A source of new genetic variation can be found in such species as Secale montanum and Secale vavilovii, which are sources of resistance to fusarium ear blight and septoria leaf blotch, while Secale vavilovii may also be a source of sterilising cytoplasm. The aim of this study was to assess the efficiency of crossing the wild species Secale vavilovii and the rye subspecies Secale cereale subsp. afghanicum, Secale cereale subsp. ancestrale, Secale cereale subsp. dighoricum, Secale cereale subsp. segetale with the crop species Secale cereale ssp. cereale, and to produce F1 hybrids and describe selected morphological traits. Observations of biometric traits indicate that the F1 crosses produced may be potential sources of variation for common rye. The greatest variation in terms of all analysed phenotypic traits combined was found for the cross combinations S. c. ssp. cereale cv. Amilo × S. c. ssp. ancestrale and S. c. ssp. cereale cv. Dańkowskie Diament × S. c. ssp. dighoricum. The hybrids showed considerable variation in the analysed biometric traits within individual cross combinations.

Analysis of the relationship between coefficients of relatedness and molecular similarity of parental forms with respect to the heterosis effect in maize

SUMMARY Within the last twenty years studies have been conducted at many research centers with the aim of dividing breeding materials into heterotic groups based on molecular markers. Molecular techniques make it possible to study the genetic purity of inbred lines, determine their genetic variability and classify breeding materials for which no information is available on their origin. This study aims to investigate relationships between coefficients of relatedness (pedigree analysis) and molecular similarity estimated on the basis of AFLP and RAPD molecular markers, between parental forms of F1 maize hybrids. Determination of these relationships will make it possible to establish a hierarchy of importance for applied methods concerning selection of parental components for heterotic crossings based on the degree of relatedness and genetic similarity. As a result of the experiment it was shown that in the case of incomplete pedigree information, in the selection of parental components for crossings we may use information concerning molecular similarity determined using AFLP markers and the Jaccard index, which to the least degree differentiates matrices of AFLP and RAPD molecular similarity.

Attempt to adapt a statistical model for the heterosis effect in maize F1 hybrids depending on the genetic distance of parental forms

Attempt to adapt a statistical model for the heterosis effect in maize F1 hybrids depending on the genetic distance of parental forms During the recent years traditional tillage techniques and procedures have been successfully used in combination with the modern molecular technologies. This enables the researchers not only to employ more objective methods of parental material selection, but also shortens the time required to breed a new variant. Many researchers tried to surmise the heterosis effect by examining the genetic distance between two parental lines. The main objective of this work was to display the correlation between the heterosis effect among the F1 generation of maize and the genetic distance between the parental components. Furthermore, an attempt was made to predict the future heterosis effect using mathematical functions. Finding a proof of those correlations would make it possible to select the parental material, used to create a new variation, more effectively and thus to reduce the number of lines tested during the experiment. Hence it would reduce the time needed for the experiments and also significantly reduce the overall cost of the research project. The research displayed that the molecular markers AFLP and RAPD are useful for predicting the formula of a new corn hybrid. They can be also used to group lines according to their origin or parentage, including those having incomplete information about their parentage. For both markers: RAPD and AFLP, the functions that best describe the correlation between the heterosis effect and the genetic distance, were: a third degree polynomial y=a+bx+cx^2+dx^3 and a linear function y = a + bx.