A novel frameshift mutant allele, <Emphasis Type="Italic">fzp</Emphasis>-<Emphasis Type="Italic">10</Emphasis>, affecting the panicle architecture of rice

The rice FRIZZY PANICLE (FZP) locus on chromosome 7, in which an ERF and acidic domain are present, is concerned with the regulation of spikelet meristem identity and the determination of panicle architecture. Many fzp mutants drastically alter panicle morphology with higher-order rachis-branches developing successively instead of the development of floral organs in these mutants. A new mutant showing the same fzp phenotype was induced by γ-ray irradiation of seeds of a rice cultivar “Gimbozu”. Examination of this fzp-like mutant for its allelism to a known allele of fzp-1, nucleotide sequence, and panicle and agronomic characteristics clearly indicated that the allele of this fzp-like mutant is located in FZP. Because there is a previously identified allele called fzp-9, we designated this new allele as fzp-10. fzp-10 has a single nucleotide (cytosine) deletion between the ERF domain and the acidic domain, which results in a frameshift mutation and a premature stop codon, thereby altering the C-terminus of the encoded protein. The degree of higher-order branching in the panicles was significantly reduced in the fzp-10 mutant compared with that of fzp-1. Moreover, the fzp-10 mutant showed highly depressed culm and panicle lengths and panicle number, as well as delayed heading dates compared with its wild type and also with fzp-1. fzp-10 has several new characteristics, its altered nucleotide position and severity of phenotype alteration, and, therefore, could be a new gene resource to examine the function of FZP and the determination of rice panicle architecture.     

Genetic analysis reveals a dominant <Emphasis Type="Italic">S</Emphasis> locus and an <Emphasis Type="Italic">S</Emphasis> suppressor locus in natural self-compatible <Emphasis Type="Italic">Brassica napus</Emphasis>

A self-incompatible (SI) line, S-1300, and its maintainer 97-wen135, a self-compatible (SC) line, were used to study the inheritance of maintenance for self-incompatibility in B. napus. The ratio of SI plants to SC plants from S-1300 × 97-wen135 F₂ and (S-1300 × 97-wen135) × 97-wen135 was 346:260 and 249:232, fitting the expected ratio of 9:7 and 1:1, respectively. Based on these observations, here we propose a genetic model in which two independent loci, S locus and S suppressor locus (sp), are predicted to control the inheritance of maintenance for self-incompatibility in B. napus. The genotypes of S-1300 and 97-wen135 are S ₁₃₀₀ S ₁₃₀₀ sp ₁₃₀₀ sp ₁₃₀₀ and S ₁₃₅ S ₁₃₅ sp ₁₃₅ sp ₁₃₅ , respectively. S ₁₃₅ is dominant to S ₁₃₀₀ , but coexistence of sp ₁₃₀₀ and sp ₁₃₅ fails to suppress S locus. Both S ₁₃₀₀ and S ₁₃₅ can be suppressed by sp ₁₃₅ , while sp ₁₃₀₀ can suppress S ₁₃₅ but not S ₁₃₀₀ . The model contains two characteristics: that a dominant S locus exists in self-compatible B. napus, and that co-suppression will occur when sp loci are heterozygous. The model has been validated by the segregation of S phenotypes in the (S-1300 × 97-wen135) × S-1300, the progenies of SC S-1300 × 97-wen135 F₂ plants and DH population developed from S-1300 × 97-wen135 F₁. This is the first study to report co-suppression of S suppressor loci in B. napus. The genetic model will be very useful for developing molecular markers linked to maintenance for self-incompatibility and for dissecting the mechanism of SI/SC in B. napus.     

Fine mapping of a <Emphasis Type="Italic">Xantha</Emphasis> mutation in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

The recessive mutation of the XANTHA gene (XNT) transforms seedlings and plants into a yellow color, visually distinguishable from normal (green) rice. Thus, it has been introduced into male sterile lines as a distinct marker for rapidly testing and efficiently increasing varietal purity in seed and paddy production of hybrid rice. To identify closely linked markers and eventually isolate the XNT gene, two mapping populations were developed by crossing the xantha mutant line Huangyu B (indica) with two wild type japonica varieties; a total of 1,720 mutant type F₂ individuals were analyzed for fine mapping using polymorphic InDel markers and high dense microsatellite markers. The XNT gene was mapped on chromosome 11, within in a fragment of ~100 kb, where 13 genes are annotated. The NP_001067671.1 gene within the delimited region is likely to be a candidate XNT gene, since it encodes ATP-dependent chloroplast protease ATP-binding subunit clp A. However, no sequence differences were observed between the mutant and its parent. Bioinformatics analysis demonstrated that four chlorophyll deficient mutations that were previously mapped on the same chromosome are located outside the XNT region, indicating XNT is a new gene. The results provide useful DNA markers not only for marker assisted selection of the xantha trait but also its eventual cloning.     

Fine mapping of a major quantitative trait locus, <Emphasis Type="Italic">qFLL6.2</Emphasis>, controlling flag leaf length and yield traits in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Fine mapping of a quantitative trait locus, qFLL6.2, controlling flag leaf length (FLL) and yield traits in rice was conducted using four sets of near isogenic lines (NILs) that were developed from a common residual heterozygote at F₇ generation of the indica rice cross Zhenshan 97/Milyang 46. Each of the NIL sets consisted of 40 lines that are S₁ progenies of ten maternal homozygotes, ten paternal homozygotes, and 20 heterozygotes differing in a portion of the 1.19-Mb interval RM3414–RM6917 on the short arm of rice chromosome 6. Analysis of phenotypic differences among the three genotypic groups in each NIL set delimited qFLL6.2 to a 62.1-kb region flanked by simple sequence repeat marker RM3414 and sequence-tagged site marker Si2944. This QTL explained 52.73% of the phenotypic variance, and the Zhenshan 97 allele increased FLL by 2.40 cm. Based on data collected from homozygous lines of three of the NIL sets, qFLL6.2 was shown to have major effects on all the three yield traits analyzed, including the number of spikelets per panicle, the number of filled grains per panicle, and grain weight per panicle. A comparison of the different groups revealed that the effect of qFLL6.2 was highly consistent across different genetic backgrounds and environments, providing a good candidate for map-based cloning and investigating the source–sink relationship in rice.     

Molecular mapping of <Emphasis Type="Italic">Pc68</Emphasis>, a crown rust resistance gene in <Emphasis Type="Italic">Avena</Emphasis><Emphasis Type="Italic">sativa</Emphasis>

Crown rust, which is caused by Puccinia coronata f. sp. avenae, P. Syd. & Syd., is the most destructive disease of cultivated oats (Avena sativa L.) throughout the world. Resistance to the disease that is based on a single gene is often short-lived because of the extremely great genetic diversity of P. coronata, which suggests that there is a need to develop oat cultivars with several resistance genes. This study aimed to identify amplified fragment length polymorphism AFLP markers that are linked to the major resistance gene, Pc68, and to amplify the F₆ genetic map from Pc68/5*Starter × UFRGS8. Seventy-eight markers with normal segregation were discovered and distributed in 12 linkage groups. The map covered 409.4 cM of the Avena sativa genome. Two AFLP markers were linked in repulsion to Pc68: U8PM22 and U8PM25, which flank the gene at 18.60 and 18.83 centiMorgans (cM), respectively. The marker U8PM25 is located in the linkage group 4_12 in the Kanota × Ogle reference oat population. These markers should be useful for transferring Pc68 to genotypes with good agronomic characteristics and for pyramiding crown rust resistance genes.     

Genetic mapping of the <Emphasis Type="Italic">qGCR6</Emphasis> locus affecting glossiness of cooked rice

A japonica variety, Koshihikari, is known to have favorable eating quality. Two rice backcross inbred lines (BILs) developed from Koshihikari exhibited significantly different glossiness of cooked rice (GCR), an eating quality trait measured using the Toyo-taste meter. Genetic analysis indicated that the genetic composition of these two BILs differed only on the short arm of chromosome 6, which led to the identification of the qGCR6 locus. Through high-resolution genetic mapping, the qGCR6 locus was further delimited to a 43.9 kb chromosomal region containing ten putative genes. The DNA marker SNP2175, which tightly links to qGCR6, was developed and can be used in marker-assisted breeding programs.     

Identification and characteristics of quantitative trait locus for grain protein content, <Emphasis Type="Italic">TGP12</Emphasis>, in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Grain protein content is an important analysis target to determine grain quality in rice. This study analyzed quantitative trait loci (QTLs) for the content of grain protein and amylose using the chromosomal segment substitution lines developed from ‘Koshihikari’ and ‘Nona Bokra’. It also evaluated the effects of target QTL on eating and cooking quality through the physical properties of cooked rice and its gel consistency. QTL analysis over 3 years detected the QTL on chromosome 12, TGP12, which consistently decreased total grain protein content via the ‘Nona Bokra’ allele. Selected CSSL with TGP12, CSSL-TGP12, showed a lower content of total grain protein in brown and milled rice, and had similar amylose content, grain size, and weight of brown rice, compared with ‘Koshihikari’. Based on the results of sodium dodecyl sulfate polyacrylamide gel electrophoresis, brown rice with CSSL-TGP12 had no remarkable decrease or loss in any specific protein. Regarding eating and cooking quality, CSSL-TGP12 did not show stable effects on physical properties, hardness, stickiness, or adherability of cooked rice or its gel consistency. These results suggest that TGP12 could be one of the key genetic factors for the alteration of grain protein content without an effect on eating or cooking quality.     

Characterization of genes <Emphasis Type="Italic">Rpp2</Emphasis>, <Emphasis Type="Italic">Rpp4</Emphasis>, and <Emphasis Type="Italic">Rpp5</Emphasis> for resistance to soybean rust

Asian rust, caused by the fungus Phakopsora pachyrhizi, is the most severe disease currently threatening soybean crops in Brazil. The development of resistant cultivars is a top priority. Genetic characterization of resistance genes is important for estimating the improvement when these genes are introduced into soybean plants and for planning breeding strategies against this disease. Here, we infected an F₂ population of 140 plants derived from a cross between ‘An-76’, a line carrying two resistance genes (Rpp2 and Rpp4), and ‘Kinoshita’, a cultivar carrying Rpp5, with a Brazilian rust population. We scored six characters of rust resistance (lesion color [LC], frequency of lesions having uredinia [%LU], number of uredinia per lesion [NoU], frequency of open uredinia [%OU], sporulation level [SL], and incubation period [IP]) to identify the genetic contributions of the three genes to these characters. Furthermore, we selected genotypes carrying these three loci in homozygosis by marker-assisted selection and evaluated their genetic effect in comparison with their ancestors, An-76, PI230970, PI459025, Kinoshita and BRS184. All three genes contributed to the phenotypes of these characters in F₂ population and when pyramided, they significantly contributed to increase the resistance in comparison to their ancestors. Rpp2, previously reported as being defeated by the same rust population, showed a large contribution to resistance, and its resistance allele seemed to be recessive. Rpp5 had the largest contribution among the three genes, especially to SL and NoU. Only Rpp5 showed a significant contribution to LC. No QTLs for IP were detected in the regions of the three genes. We consider that these genes could contribute differently to resistance to soybean rust, and that genetic background plays an important role in Rpp2 activity. All three loci together worked additively to increase resistance when they were pyramided in a single genotype indicating that the pyramiding strategy is one good breeding strategy to increase soybean rust resistance.     

Modelling rice competition with <Emphasis Type="Italic">Echinochloa crus-galli</Emphasis> and <Emphasis Type="Italic">Eleocharis kuroguwai</Emphasis> in transplanted rice cultivation

Field experiments were conducted to investigate rice — Echinochloa crus-galli and rice — Eleocharis kuroguwai competition under transplanted rice cultivation in four major rice production areas; Suwon, Daejeon, Iksan, and Naju in Korea. Rice yield data were used to predict rice yield as a function of plant densities of E. crus-galli and E. kuroguwai using a rectangular hyperbola and to determine economic threshold (ET) levels of the weeds. Both weed species significantly reduced number of tillers at early rice growth stage, resulting in significant reduction in number of spikes, and the other yield components such as number of grains, maturity and 1,000-grain weight at later growth stage. The weed competitivity represented by parameter ranged from 0.0145 to 0.0346 for E. crus-galli and from 0.0037 to 0.0187 for E. kuroguwai, indicating that the competition effect of E. crus-galli on rice yield was slightly greater than that of E. kuroguwai. The ET values of E. crus-galli were between 0.298 and 1.078 plants m⁻², while those of E. kuroguwai were between 0.848 and 5.298 plants m⁻², depending on weed competitivity and herbicide price. Therefore, our results can be used to support decision-making on herbicide application for E. crus-galli and E. kuroguwai management in transplanted rice cultivation.     

Mapping of new resistance (<Emphasis Type="Italic">Vr2</Emphasis>, <Emphasis Type="Italic">Rm1</Emphasis>) and ornamental (<Emphasis Type="Italic">Di2</Emphasis>, <Emphasis Type="Italic">pl</Emphasis>) Mendelian trait loci in peach

Peach powdery mildew is one of the major diseases of the peach. Various sources of resistance to PPM have thus been identified, including the single dominant locus Vr2 carried by the peach rootstock ‘Pamirskij 5’. To map Vr2, a linkage map based on microsatellite markers was constructed from the F₂ progeny (WP²) derived from the cross ‘Weeping Flower Peach’ × ‘Pamirskij 5’. Self-pollinations of the parents were also performed. Under greenhouse conditions, all progenies were scored after artificial inoculations in two classes of reactions to PPM (resistant/susceptible). In addition to Vr2, WP² segregated for three other traits from ‘Weeping Flower Peach’: Rm1 for green peach aphid resistance, Di2 for double-flower and pl for weeping-growth habit. With their genomic locations unknown or underdocumented, all were phenotyped as Mendelian characters and mapped: Vr2 mapped at the top of LG8, at 3.3 cM, close to the CPSCT018 marker; Rm1 mapped at the bottom of LG1, at a position of 116.5 cM, cosegregating with the UDAp-467 marker and in the same region as Rm2 from ‘Rubira’^®; Di2 mapped at 28.8 cM on LG6, close to the MA027a marker; and pl mapped at 44.1 cM on LG3 between the MA039a and SSRLG3_16m46 markers. Furthermore, this study revealed, for the first time, a pseudo-linkage between two traits of the peach: Vr2 and the Gr locus, which controls the red/green color of foliage. The present work therefore constitutes a significant preliminary step for implementing marker-assisted selection for the four major traits targeted in this study.     

A simple,rapid and reliable bioassay for evaluating seedling vigor under submergence in <Emphasis Type="Italic">indica</Emphasis> and <Emphasis Type="Italic">japonica</Emphasis> rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Submergence is a major stress causing yield losses particularly in the direct-seeded rice cultivation system and necessitates the development of a simple, rapid and reliable bioassay for a large scale screening of rice germplasms with tolerance against submergence stress. We developed two new bioassay methods that were based primarily on the seedling vigor evaluated by the ability of fast shoot elongation under submerged conditions, and compared their effectiveness with two other available methods. All four bioassay methods using cultivars of 7 indica and 6 japonica types revealed significant and consistent cultivar differences in seedling vigor under submergence and/or submergence tolerance. Japonica cultivars were more vigorous than indica cultivars, with Nipponbare being the most vigorous. The simplest test tube method showed the highest correlations to all other methods. Our results suggest that seedling vigor serves as a submergence avoidance mechanism and confers tolerance on rice seedlings to flooding during early crop establishment. A possible relationship is discussed between seedling vigor based on fast shoot elongation and submergence tolerance defined by recovery from submergence stress.     

Expression of <Emphasis Type="Italic">Bruguiera gymnorhiza</Emphasis><Emphasis Type="Italic">BgARP1</Emphasis> enhances salt tolerance in transgenic <Emphasis Type="Italic">Arabidopsis</Emphasis> plants

We have previously reported that expression of salt-responsive genes, including Bruguiera gymnorhiza ankyrin repeat protein 1 (BgARP1), enhances salt tolerance in both Agrobacterium tumefaciens and Arabidopsis. In this report, we further characterized BgARP1-expressing Arabidopsis to elucidate the role of BgARP1 in salt tolerance. BgARP1-expressing plants exhibited more vigorous growth than wild-type plants on MS plates containing 125–175 mM NaCl. Real-time PCR analysis showed enhanced induction of osmotin34 in the 2-week-old transformants under 125 mM NaCl. It was also showed that induction of typical salt-responsive genes, including RD29A, RD29B, and RD22, was blunted and delayed in the 4-week-old transformants during 24 h after 200 mM NaCl treatment. Ion content analysis showed that transgenic plants contained more K⁺, Ca²⁺, and NO₃ ⁻, and less NH₄ ⁺, than wild-type plants grown in 200 mM NaCl. Our results suggest that BgARP1-expressing plants may reduce salt stress by up-regulating osmotin34 gene expression and maintaining K⁺ homeostasis and regulating Ca²⁺ content. These results indicate that BgARP1 is functional on a heterogeneous background.     

Resistance screening of <Emphasis Type="Italic">Coffea</Emphasis> spp. accessions for <Emphasis Type="Italic">Pratylenchus coffeae</Emphasis> and <Emphasis Type="Italic">Radopholus arabocoffeae</Emphasis> in Vietnam

Coffee varieties with resistance for the plant-parasitic nematodes Pratylenchus coffeae and Radopholus arabocoffeae are limited in Vietnam. A selection of imported varieties and high yield varieties of Arabica coffee in Vietnam were evaluated for resistance to both plant-parasitic nematode species in Northern Vietnam. The same experiments were carried out with hybrid arabica coffee, three selected clones of Coffea canephora and one clone of Coffea excelsa in the Western Highland of Vietnam. The screened coffee accessions from Ethiopia (KH1, KH13, KH20, KH21, KH29, and KH31) were susceptible and good host for P. coffeae. Also accessions 90P4 (Portugal) and Oro azteca (Mexico) had a reproduction factor Rf > 1. Pluma Hidalgo (Mexico), 90/6 (Vietnam), 90P3 (Portugal), 90P2 (Vietnam), Variedad (Mexico), 90T (Portugal), and Garnica (Mexico) were poor hosts (Rf < 1) but not tolerant to P. coffeae, expressed by a reduction of root weight compared to untreated control plants. Most of the coffee accessions tested in Northern Vietnam were intolerant to R. arabocoffeae, except 90T which showed no reduction of root weight, even at high initial nematode densities (4,000/pot). Good hosts for R. arabocoffeae were Variedad, KH1, KH21, KH29, KH20, KH31, and KH13 with Rf > 1. Pluma Hidalgo, 90/6, 90P3, 90P2, 90T, Oro azteca, and Garnica were poor hosts (Rf < 1). In the Western Highland experiment, all arabica coffee accessions were susceptible for P. coffeae with Rf ranging from 1.41 to 1.59. Tolerance to P. coffeae was found in C. liberica var. Dewevrei, Hong34 and Nhuantren. Coffea excelsa, Hong34, Nhuantren, and H1C19 were tolerant to R. arabocoffeae at the highest inoculation density (4,000 nematodes/pot). The most susceptible accessions were Nhuantren and K55. Resistance (Rf < 1) to R. arabocoffeae was found in C. liberica var. Dewevrei and Hong34. This article reports on the first screening for resistance and tolerance to P. coffeae and R. arabocoffeae in coffee accessions in Vietnam and shows promising results for enhanced coffee-breeding.     

Role of <Emphasis Type="Italic">Berberis</Emphasis> spp. as alternate hosts in generating new races of <Emphasis Type="Italic">Puccinia graminis</Emphasis> and <Emphasis Type="Italic">P. striiformis</Emphasis>

The common barberry and several other Berberis spp. serve as the alternate hosts to two important rust pathogens of small grains and grasses, Puccinia graminis and P. striiformis. Barberry eradication has been practiced for centuries as a means to control stem rust. Diverse virulence variations have been observed in populations of P. graminis f. sp. tritici that were associated with susceptible barberries in North America. Barberry likely has played a role in generating new races of P. striiformis f. sp. tritici in some regions in the world. Several North American stem rust races, namely races 56, 15B and QCC, initially originated from barberry, were subsequently responsible for generating large-scale epidemics. Thus, sexual cycles on Berberis spp. may generate virulence combinations that could have serious consequences to cereal crop production.     

Fine mapping of the <Emphasis Type="Italic">R</Emphasis><Subscript><Emphasis Type="Italic">SC14Q</Emphasis></Subscript> locus for resistance to soybean mosaic virus in soybean

In maize hybrid seed production, some hybrid seed in the field must be harvested before reaching physiological maturity because of the potential damage from early fall frosts. However, early harvesting can result in poor quality and low vigor of seeds. To elucidate the genetic basis of seed vigor at different stages of maturity, the seeds of a set of recombinant inbred line (RIL) populations at three different stages of maturity (32, 40, and 45 days after pollination; DAP), were used to evaluate the performance of four traits for seed vigor in the field. A genetic linkage map was constructed using 217 SSR makers covering 2438.2 cM with an average interval of 11.2 cM. The results showed that there were significant positive relationships among the four traits of seed vigor at all three sampling times, and all showed quantitative changes according to the degree of maturity of the seeds. However, the four traits of seed vigor were not significantly related to the 100-kernel weight. In total, we detected 16 different QTL for the four measured traits of seed vigor at three sampling times; five QTL were for germination energy, three for germination percentage, four for germination index, and four for vigor index. Interestingly, four QTL for seed vigor, which were detected at all three sampling times, were located in the same region on chromosome 7. This result implies that this region of chromosome 7 is important for seed vigor of seeds harvested before they reach physiological maturity.     

Successful induction of trigenomic hexaploid <Emphasis Type="Italic">Brassica</Emphasis> from a triploid hybrid of <Emphasis Type="Italic">B.</Emphasis><Emphasis Type="Italic">napus</Emphasis> L. and <Emphasis Type="Italic">B. nigra</Emphasis> (L.) Koch

A triploid hybrid with an ABC genome constitution, produced from an interspecific cross between Brassica napus (AACC genome) and B. nigra (BB genome), was used as source material for chromosome doubling. Two approaches were undertaken for the production of hexaploids: firstly, by self-pollination and open-pollination of the triploid hybrid; and secondly, by application of colchicine to axillary meristems of triploid plants. Sixteen seeds were harvested from triploid plants and two seedlings were confirmed to be hexaploids with 54 chromosomes. Pollen viability increased from 13% in triploids to a maximum of 49% in hexaploids. Petal length increased from 1.3 cm (triploid) to 1.9 cm and 1.8 cm in the two hexaploids and longest stamen length increased from 0.9 cm (triploid) to 1.1 cm in the hexaploids. Pollen grains were longer in hexaploids (43.7 and 46.3 μm) compared to the triploid (25.4 μm). A few aneuploid offsprings were also observed, with chromosome number ranging from 34 to 48. This study shows that trigenomic hexaploids can be produced in Brassica through interspecific hybridisation of B. napus and B. nigra followed by colchicine treatment.     

RDA derived <Emphasis Type="Italic">Oryza minuta</Emphasis>-specific clones to probe genomic conservation across <Emphasis Type="Italic">Oryza</Emphasis> and introgression into rice (<Emphasis Type="Italic">O. sativa</Emphasis> L.)

Molecular markers have been successfully used in rice breeding however available markers based on Oryza sativa sequences are not efficient to monitor alien introgression from distant genomes of Oryza. We developed O. minuta (2n = 48, BBCC)-specific clones comprising of 105 clones (266–715 bp) from the initial library composed of 1,920 clones against O. sativa by representational difference analysis (RDA), a subtractive cloning method and validated through Southern blot hybridization. Chromosomal location of O. minuta-specific clones was identified by hybridization with the genomic DNA of eight monosomic alien additional lines (MAALs). The 37 clones were located either on chromosomes 6, 7, or 12. Different hybridization patterns between O. minuta-specific clones and wild species such as O. punctata, O. officinalis, O. rhizomatis, O. australiensis, and O. ridleyi were observed indicating conservation of the O. minuta fragments across Oryza spp. A highly repetitive clone, OmSC45 hybridized with O. minuta and O. australiensis (EE), and was found in 6,500 and 9,000 copies, respectively, suggesting an independent and exponential amplification of the fragment in both species during the evolution of Oryza. Hybridization of 105 O. minuta specific clones with BB- and CC-genome wild Oryza species resulted in the identification of 4 BB-genome-specific and 14 CC-genome-specific clones. OmSC45 was identified as a fragment of RIRE1, an LTR-retrotransposon. Furthermore this clone was introgressed from O. minuta into the advanced breeding lines of O. sativa.     

Hybrids of <Emphasis Type="Italic">Passiflora</Emphasis>: <Emphasis Type="Italic">P. gardneri</Emphasis> versus <Emphasis Type="Italic">P. gibertii,</Emphasis> confirmation of paternity,morphological and cytogenetic characterization

Two new varieties of interspecific hybrids of Passiflora have been developed from the cross between P. gardneri versus P. gibertii, both registered under the Passiflora Society International. Twelve putative hybrids were analyzed. Hybridization was confirmed using RAPD and SSR markers. Primer UBC11 (5′-CCGGCCTTAC-3′) generated informative bands. Primer SSR Pe75 has amplified species-specific fragments and a heterozygote status was observed with two parent bands 300 and 350 bp. The molecular markers generated have been analyzed for the presence or absence of specific informative bands. Based on the morphological characterization, we have identified two hybrid varieties: P. ‘Gabriela’ and P. ‘Bella’. P. ‘Gabriela’ produced flowers in bluish tones, bluish petals on the adaxial and abaxial faces, light blue sepals on the adaxial and light green on the abaxial faces, corona with the base of filaments in intense lilac color and white apex. P. ‘Bella’ produced flowers in lilac tones, intense lilac petals on the adaxial and abaxial faces, dark lilac sepals with whitish edges on the adaxial and light green on the abaxial faces, corona with the base of filaments in intense lilac color and white apex. The cytogenetic analysis verified that the hybrids have the same chromosomal number as the parents (2n = 18); the formation of bivalents between the homeologous chromosomes (n = 9) was observad, leading to regular meiosis, which allows the sexual reproduction and use of these hybrids in breeding programs.