Dorota Olszewska

Induced androgenesis of Capsicum frutescens L.

The aim of the research was to make a preliminary determination of the effectiveness of the induction of haploids in Capsicum frutescens L. In order to induce androgenesis red and yellow fruit forms of species were used, each bred by the researchers on their own. The experiment was performed in October. Anther cultures were conducted according to a modified method developed by Dumas et al. (1981) for C. annuum L. The anthers were laid on CP medium containing 0.01 mg dm−3 2.4-D and 0.01 mg dm−3 kinetin, with the addition of 0.5 g dm−3 of activated carbon and 5 mg×dm−3 of silver nitrate, solidified with 8 g dm−3 of agar. The cultures were incubated in the dark at 35 deg C for 8 days. Next they were transferred to 25 deg C under a 12-hour photoperiod. After 14 days of induction, anthers were transferred to R1 medium supplemented with 0.1 mg dm−3 kinetin. Obtained embryos were subsequently transplanted onto V3 hormone-free medium and well growing plants were planted in greenhouses. The efficiency of androgenesis for both C. frutescens L. forms was relatively low and it did not exceed 5%. The ploidy level of the resulting plants was determined by flow-cytometric analysis. The regenerants consisted of about equal numbers of haploids and diploids. Additionally, among plants regenerated from anthers of yellow fruit forms, two mixoploids were observed.

The assessment of doubled haploid lines obtained in pepper (Capsicum annuum L.) anther culture

Abstract The aim of the research was the analysis of 11 DH-R2 pepper (Capsicum annuum L.) lines, obtained in anther cultures of ‘(ATZ1 × PO)’ F1, ‘(ATZ1 × CDT)’ F1 and ‘(ATZ1 × TG)’ F1 hybrids. To determine the genetic homogeneity of anther-derived lines, the biometrical characteristics of fruits, as well as fruit colour and shape inheritance, were analysed. The biometrical analysis determined the highest phenotype uniformity in androgenic lines of ‘(ATZ1 × PO)’ F1. Based on the fruit shape and colour variation, it was possible to determine the microspore origin of androgenic diploids obtained in anther cultures of ‘(ATZ1 × TG)’ F1. Additionally, enzyme analysis of four isozymes (PGM, PGI, IDH and MDH) showed that isocitrate dehydrogenase identified anther-derived diploids of hybrids between ‘ATZ1’ and ‘TG’, as well as those between ‘ATZ1’ and ‘CDT’, lines.

Study of individual plant responsiveness in anther cultures of selected pepper (Capsicum spp.) genotypes

Abstract One of the key factors determining the effectiveness of pepper anther cultures is donor plant genotype. The stock material for androgenic embryos inductions is usually made up of hybrid forms, since the higher the degree of heterozygosity, the greater the chances of producing regenerates with unique genotypes. The aim of the presented research was to evaluate individual plant reaction in anther cultures for the C. annuum hybrid (‘ATZ1’ × ‘TG’)F2, interspecific hybrid (C. frutescens × C. chinense)F2 and androgenic DH line AT6. The effectiveness of androgenesis was determined individually for each plant as the percentage of the embryos produced compared to the total number of anthers cultured. In the hybrid (‘ATZ1’ × ‘TG’)F2, anthers of 19 out of 20 plants evaluated produced embryos at a rate of 0.5 to 16.5%. Anthers of the AT6 DH line formed embryos considerably less frequently. A positive reaction was recorded for 13 out of 20 plants and the effectiveness of androgenesis did not exceed 3% for this genotype. The lowest androgenic response was recorded for the hybrid (C. frutescens × C. chinense)F2, where embryo development was observed in only five out of 19 plants and the effectiveness of androgenesis did not exceed 2%. The ploidy level of the regenerates was defined cytometrically. The analysis revealed the presence of haploid and diploid plants among the regenerates of all the genotypes evaluated.

Androgenic response of Capsicum interspecific hybrids and capsaicinoid characteristics of DH lines

Summary In the research on induced androgenesis, eight groups of plants, the progeny of interspecific hybrid of Capsicum frutescens L. x C. annuum L., were used. Half of them were standard hard-flesh forms, while the others have represented SS or Ss genotype conditioning the soft flesh of ripe fruit. Anthers from the plants of six groups produced mixoploid callus and the DNA content ranged from 1C to 16C. Three groups formed embryos which converted into plants. The total number of regenerants was 19, included both androgenic haploids (13) and diploids (6). The results did not allow to present the simple relationship between the physiological feature of soft-flesh and the effectiveness of androgenesis. Pungent, soft-flesh genotypes appeared as a poor responsive in anther culture. The R2 and R3 generation of two soft-flesh diploids, evaluated in two-year experiments, showed full phenotypic uniformity, proofing the androgenic origin of diploids. These DH lines were different with regard to capsaicinoid profiles. The content of capsaicinoids ranged from 0.056 to 2.170 and from 0.019 to 1.610 g*kg-1 for capsaicin and dihydrocapsaicin, respectively. The highest concentration of the compounds was observed in the placenta. Although the androgenic effectiveness was not fully satisfactory, the doubled haploid technology can be used for the rapid genetic stabilization of soft-flesh Capsicum spp. recombinants and the special attention should be paid to the spontaneous androdiploids.

Biometrical Assessment of Interspecific Hybrids of Capsicum Genus

Biometrical Assessment of Interspecific Hybrids of Capsicum Genus The F1 hybrids obtained as the result of interspecific crosses: C. annuum x C. frutescens, C. frutescens x C. annuum, C. frutescens x C. chinense and C. chinense x C. frutescens were analysed biometrically. The plants were cultured in unheated foil tent. Yield and the number of fruit from plant were qualified. For ten plants of each of the hybrids detailed fruit analysis were performed. The tested traits were: weight of fruit, length, width, technological weight and weight of pericarp, pericarp thickness, the weight of placenta without seeds, the weight of dry seeds and the dry matter content. The analysis of variance was conducted on the obtained results. The tested hybrids were characterised by the large differentiation of the estimated characters. The hybrids obtained from crosses: C. annuum x C. frutescens and C. frutescens x C. annuum seem to be the most valuable material for the future pepper breeding work. Fruits of these hybrids combine high weight, typical for cultivated forms of C. annuum with increased dry matter content characteristic for C. frutescens. These materials will be used as the parental forms of homozygous lines which possess traits valuable in genetic improvement of pepper. Ocena Użytkowa Mieszańców Międzygatunkowych Z Rodzaju Capsicum Ocenie biometrycznej poddano mieszańce pokolenia F1 otrzymane w wyniku krzyżowań oddalonych: C. annuum x C. frutescens, C. frutescens x C. annuum, C. frutescens x C. chinense i C. chinense x C. frutescens. Uprawę roślin prowadzono w nieogrzewanym tunelu foliowym. Określono plon i liczbę owoców z uzyskanych mieszańców. Owoce dziesięciu wybranych roślin każdego genotypu, poddano szczegółowej ocenie biometrycznej. Oznaczono: masę owocu, długość, szerokość, masę technologiczną i biologiczną, grubość ścian, masę łożyska bez nasion, masę nasion suchych oraz suchą masę owocu. Wyniki poddano analizie statystycznej stosując jednoczynnikową analizę wariancji. Stwierdzono, że badane mieszańce charakteryzowały się dużym zróżnicowaniem pod względem ocenianych parametrów. Na szczególną uwagę w dalszych pracach hodowlanych zasługuje materiał pochodzący z krzyżowań: C. annuum x C. frutescens i C. frutescens x C. annuum. Owoce tych mieszańców łączą wysoką masę, typową dla uprawnych form C. annuum, z podwyższoną zawartością suchej masy, charakterystyczną dla C. frutescens. Materiały te posłużą jako formy wyjściowe do uzyskania homozygotycznych linii, łączących te pożądane właściwości, przydatne w genetycznym doskonaleniu papryki rocznej.