F3 Lines Research Articles

Development of drought‐tolerant breeding lines derived from Helianthus annuus × H. argophyllus interspecific crosses

AbstractHelianthus argophyllus is a wild species known as “silver sunflower”, which possesses several traits, including morphological traits that increase drought tolerance. Therefore, introgressions between chosen cultivated lines and two H. argophyllus accessions were made, and segregating generations were established. Important agronomic traits including single heading, high pollen fertility, silver canopy (indicating more cuticular wax), and content of cuticular waxes and oil were selected over six segregating generations. The resulting F6 lines showed introgression of water saving traits, as they had lower excise leaf water loss, with comparable yield to standard checks. However, these F6 lines were late maturing and showed poor flowering synchronization between the cultivated and introgressed lines. Introgressed line “D‐22” was particularly promising as a breeding line, with superior agronomic and drought resistance traits. This line had the potential to be used as an inbred parental line for introgression of drought resistance traits into elite sunflower germplasm. Combining ability analysis of the introgressed lines further showed their potential for heterosis breeding or to be used as parental lines in breeding programme.

Integration of Phenotype and Hormone Data during Adventitious Rooting in Carnation (Dianthus caryophyllus L.) Stem Cuttings.

The rooting of stem cuttings is a highly efficient procedure for the vegetative propagation of ornamental plants. In cultivated carnations, an increased auxin level in the stem cutting base produced by active auxin transport from the leaves triggers adventitious root (AR) formation from the cambium. To provide additional insight into the physiological and genetic basis of this complex trait, we studied AR formation in a collection of 159 F1 lines derived from a cross between two hybrid cultivars (2003 R 8 and 2101-02 MFR) showing contrasting rooting performances. In three different experiments, time-series for several stem and root architectural traits were quantified in detail in a subset of these double-cross hybrid lines displaying extreme rooting phenotypes and their parental genotypes. Our results indicate that the water content and area of the AR system directly contributed to the shoot water content and shoot growth. Moreover, morphometric data and rooting quality parameters were found to be associated with some stress-related metabolites such as 1-aminocyclopropane-1-carboxylic acid (ACC), the ethylene precursor, and the conjugated auxin indol-3-acetic acid-aspartic acid (IAA-Asp).

Thatcher wheat line RL6149 carries Lr64 and a second leaf rust resistance gene on chromosome 1DS.

The leaf rust resistance gene Lr64 in the Thatcher wheat RL6149 was mapped to chromosome 6AL with SNP and KASP markers and a second leaf rust resistance gene was mapped to chromosome 1DS. RL6149, a near-isogenic line of Thatcher wheat, carries leaf rust resistance gene Lr64 on chromosome arm 6AL. The objective of this study was to develop molecular markers that can be easily used to select wheat lines with Lr64. RL6149 was crossed with Thatcher and F2 plants derived from a single F1 plant were advanced to F6 lines by single seed descent. The 100 F7 recombinant inbred lines (RIL) were inoculated with two races of P.triticina that differed widely for virulence in order to identify resistant and susceptible RIL. Thirty RIL that differed for resistance and the parental lines were genotyped with the 90K Infinium iSelect single nucleotide polymorphism (SNP) array to find closely linked markers with Lr64. Seven linked SNPs on chromosome arm 6AL were converted into Kompetitive Allele Specific PCR (KASP) markers that were genotyped on the 100 RIL. A genetic linkage map for the seven KASP markers spanned 19.1cM on chromosome arm 6AL. KASP marker K-IWB59855 was tightly linked to Lr64. A second unexpected gene for leaf rust resistance also segregated in the F7 lines. Four KASP markers that spanned 18.6cM located the gene on chromosome 1DS. The KASP marker K-IWB38437 was tightly linked to the second leaf rust resistance gene.

Abstract 1926: Ba/F3 NTRK cell panel, a powerful cell model for NTRK inhibitor discovery and development

Abstract NTRK (Neurotrophic tyrosine kinase receptor)family, also named as TRK (Tropomyosin receptor kinase),is composedof three transmembrane protein receptors, TrkA, TrkB and TrkC,which play important rolesin neuronal differentiation and survival. Over-activation of NTRK1, NTRK2 and NTRK3 due to chromosomal rearrangement and mutations, was found in congenital fibrosarcoma, secretory breast carcinoma cancer and other types ofcancer. The identification of NTRK fusions as diver cancer genes has led to rapid development of anticancer therapeutic agents, including LOXO101, LOXO195 and TPX0005.Ba/F3 line is a popular system for studying both kinases and their inhibitors, because some protein kinases can render the Ba/F3 cells to be depended on the activation of the kinases instead of IL-3 supplement, while their inhibitors can antagonize the kinase-dependent growth effects. Our group used Ba/F3 cells togenerate a celllinepanel with 14 different NTRK fusion genes or mutations for NTRK inhibitor screening and development. Inaddition to use the cell lines for in vitro assays, thetransformed Ba/F3 linescan grow well in immune-deficient miceas in vivo models. LOXO101—a NTRK inhibitor—was used to test tumor growth inhibition, the results showedthat threewild-type fusion cell lineswere sensitive to LOXO101, but not other tumor models containing NTRK gatekeeper mutations. All the tumor models were sensitive to TPX0005, another NTRK inhibitor. Ourdata indicatethatthe celllinepanel of Ba/F3is apowerful cell model for new NTRK inhibitor discovery and development. Citation Format: Feng Hao, Zhaoshuai Bai, Guoqian Wang, Feng He, Changpeng Liu, Jinying Ning. Ba/F3 NTRK cell panel, a powerful cell model for NTRK inhibitor discovery and development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1926.

Agronomic Performances of Rice Lines on Non-Tidal Swampland

A successful rice production on swampland would require a planting material from high yielding varieties adaptated to the swampy ecosystem. This study was carried out to compare the growth and yield characteristics of five rice lines and a check variety as grown on non-tidal swampland. The lines were F4 generation of bulk selection from the crosses involving Bengkulu swamp rice landraces (Hanafi Putih, Tigo-tigo, Harum Curup, and Lubuk Durian) and high yielding varieties for the irrigated field (Sidenuk and Bestari). The trial was conducted on a shallow non-tidal swampland with stagnant inundation no more than 50 cm in depth often occurred during the plant life cycle. The lines and the check variety (Inpara 4) were arranged in a randomized complete block design with three replications. Observations were made for the agronomic performances of the plant, including plant height, total tiller number clump-1, effective tiller number clump-1, heading date, maturity date, panicle length, grain number panicle-1, 100-grain weight, and grain yield clump-1. Significant variation among the genotypes was found for all observed traits. On average, the evaluated lines showed comparable growth and yield performances to the check variety. Tigo-tigo × Bestari was the tallest line and potential for medium depth swampland. This line showed good overall agronomic performances and yielded relatively higher than the check variety, but delayed in attaining maturity. For shallow swampland, Hanafi Putih x Sidenuk exhibited the most potent line by having good overall agronomic and yield performances, except late in maturity. For early maturing line, Lubuk Durian x Hanafi Putih showed its potential for shallow swampland. Although this line was not the best, it showed better overall agronomic performances than the check variety. Keywords: F4 lines, growth and yield performance, rice landrace, swampland, plant maturity

Partial Loss of Inheritable Type I Resistance of Codling Moth to Cydia pomonella qranulovirus.

Current knowledge of the field resistance of codling moth (CM, Cydia pomonella, L) against Cydia pomonella granulovirus (CpGV) is based mainly on the interaction between the Mexican isolate CpGV-M and CpRR1, a genetically homogeneous CM inbreed line carrying type I resistance. The resistance level of laboratory-reared CpRR1 to CpGV-M was recently found to have decreased considerably, compared to the initially high resistance. To understand the background of this phenomenon, CpRR1 larvae were exposed over several generations to CpGV-M for re-selection of the original resistance level. After five and seven generations of selection, new CpRR1_F5 and CpRR1_F7 lines were established. The resistance ratio of these selected lines was determined by full range bioassays. The CpRR1_F5 strain regained a higher level of resistance against CpGV up to 104-fold based on LC50 values compared to susceptible larvae (CpS), which indicated that the absence of virus selection had resulted in a reduction of resistance under laboratory rearing conditions. In addition, some fitness costs of fecundity were observed in CpRR1_F5. Single-pair crossings between CpRR1_F5 or CpRR1_F7 with susceptible CpS moths revealed a dominant but not fully sex-linked inheritance, which suggests a partial loss of previous resistance traits in CpRR1.

Characterization of Agro-morphological Traits of 21 F5 Lines of Aus Rice

The investigation was carried out under field conditions to characterize agro-morphological traits of twenty-one (21) advanced Aus rice lines (F5). The experiment was conducted in a randomized complete block design (RCBD). The field was divided into three blocks; each block was sub-divided into 21 plots (lines) where genotypes were randomly assigned. The experiment was conducted during the period of Transplanting Aus season (April 2015 to August 2015) at the genetics and plant breeding experimental field of Sher-e-Bangla Agricultural University, Bangladesh. All the genotypes were characterized and categorized as per the descriptors developed by Biodiversity International, IRRI and WARDA-2007 for DUS test of inbred rice. All the genotypes were grouped and classified as well as described based on morphological characters as per descriptors so that all the observed genotypes containing described characters can be easily evaluated and identified at a glance for further studies.

Transgressive segregation and maternal genetic effects of non–target site fluazifop-P-butyl tolerance in Zoysia spp.

AbstractZoysia germplasm exhibit different levels of sensitivity to fluazifop-P-butyl, but the genetic factors responsible for such differences are unknown. Segregation patterns of the fluazifop-P-butyl tolerance trait were studied under greenhouse conditions. In total, 244 F1 lines were generated from multiple crosses between the tolerant line 5337-2 (non–target site tolerance) and three more-sensitive lines (123, 252, and 5330-23). Progeny segregation showed that fluazifop-P-butyl tolerance within zoysiagrass (Zoysia spp.) is expressed as a quantitative trait with a wide range of intermediate phenotypes between parental phenotypes. Transgressive segregation was extensive and largely favored susceptibility in most families, but was especially evident for 5337-2 × 123 and 5337-2 × 5330-23. The segregation patterns for biomass reduction and percent injury were different within reciprocal crosses and among three different family crosses. Reciprocal effects were observed in growth reduction for 5337-2 × 5330-23, in percent injury at 3 wk after the treatment (WAT), and for 5337-2 × 252 at 6 WAT. This indicated that fluazifop-P-butyl tolerance was not completely controlled by nuclear genetic factors in 5337-2 and maternal/cytoplasmic inheritance was also partially responsible. These results suggested that fluazifop-P-butyl tolerance may be attributed to multiple genetic mechanisms, which could present a challenge for future breeding efforts because of the difficulty of fixing multiple traits within a breeding population.

Development of a drought stress-resistant rice restorer line through Oryza sativa–rufipogon hybridization

Restorer line F6 (Oryza sativa L. ssp. indica) has been widely used in hybrid rice breeding systems in southern China. However, line F6 is susceptible to drought stress, which restricts its utilization in many areas. Dongxiang wild rice (DXWR, Oryza rufipogon Griff.) has strong drought stress resistance, but the molecular factors responsible for drought resistance in DXWR remain unknown. In this study, we used the combination of phenotypic selection and molecular marker-assisted selection (MAS) to improve the drought stress resistance of line F6 by introgression of qSDT12-2, a large effect drought stress-related quantitative trait locus identified in DXWR. Molecular MAS was carried out using linked marker RM1226, which is associated with qSDT12-2. Genomic background assessmentwas performed using 112 polymorphic markers. Finally, a stable drought stress-resistant backcross inbred line (BIL) was developed from a BC5F5 population, termed BIL627. Genetic constitution analysis revealed that the genome of BIL627 is almost identical (99.1%) to that of the restorer line F6. Further, BIL627 showed no yield penalty and no decrease in restorationability under normal conditions. Taken together, our findings reveal the intrinsic value of using genetic resources present in wild species of Oryza to improve undesirable traits found in cultivated rice.

Resistance to red mite in Coffea arabica genotype introgressed with Coffea racemosa genes

The aim of this study was to assess the resistance to red mite (Oligonychus ilicis) in Coffea arabica genotypes with introgression of genes from a different species (Coffea racemosa). The experiment was conducted in a greenhouse at IAPAR (Londrina, PR, Brazil), between January 2016 and January 2017. The experiment was conducted in a completely randomized design with five genotypes, 12 replications of one plant per plot. The C. arabica cultivars IPR 100, IPR 99 and IPR 103 were evaluated as well as an F4 Arabica coffee line IAPAR H0113-40-26-10 with introgressed C. racemosa genes. Catuaí Vermelho IAC 99 cultivar, which is a pure C. arabica, was used as a susceptible control. In conditions of high natural infestation of red mite, the resistance of coffee genotypes was evaluated using a standard visual evaluation in January 2017. This evaluation was based on the percentage of leaf area with typical symptoms caused by this mite. Only one genotype, the F4 line IAPAR H0113-40-26-10 showed resistance to the red mite because present less leaf area with symptoms compared to other genotypes. The Arabica coffee cultivars IPR 99, IPR 100 and IPR 103 are as susceptible to red mite as to the susceptible control Catuaí Vermelho IAC 99.

Genetic dissection of root morphological traits as related to potassium use efficiency in rapeseed under two contrasting potassium levels by hydroponics.

To reveal the genetic basis of potassium use efficiency (KUE) in rapeseed, root morphology (RM), biomass and KUE-related traits were measured in a recombinant inbred line population with 175 F7 lines that were subjected to high-potassium (HK) and low-potassium (LK) treatments by hydroponics. A total of 109 significant QTLs were identified to be associated with the examined traits. Sixty-one of these QTLs were integrated into nine stable QTLs. The higher heritability for RM and biomass traits and lower heritability for KUE-related traits, as well as nine stable QTLs for RM traits and only two for KUE-related traits, suggested that regulating RM traits would be more effective than selecting KUE traits directly to improve KUE by marker-assisted selection. Furthermore, the integration of stable QTLs identified in the HK, LK, high-nitrogen (HN) and low-nitrogen (LN) conditions gave 10 QTL clusters. Seven of these clusters were classified into major QTLs that explained 7.4%-23.7% of the total phenotypic variation. Five of the major QTL clusters were detected under all of the treated conditions, and four clusters were specifically detected under the LK and LN conditions. These common and specific QTL clusters may be useful for the simultaneous improvement of multiple traits by marker-assisted selection.

Field resistance of advanced breeding lines of upland cotton to ramulosis caused by Colletotrichum gossypii var. cephalosporioides

Cotton ramulosis caused by Colletotrichum gossypii var. cephalosporioides is the main disease in the cotton growing areas of South America. Commercially available cultivars do not exhibit ramulosis resistance and thus it is necessary to identify sources of resistance. This study evaluated the Colombian LCER collection of advanced breeding lines (ABLs) of Upland cotton for ramulosis resistance. LCER is composed of F6 lines derived from crosses between lines with African and Colombian ancestry (LC collection) and high yielding cultivars from USA, Brazil and Africa adapted to the monsoon and savanna climate of the Colombian Caribbean. Disease development was measured thirteen weeks after planting using a qualitative scale designed for high levels of ramulosis intensity (absence of healthy plants and high proportions of dwarf plants for susceptible cultivars). A ramulosis resistant scale (RSC) was developed from these disease assessments to evaluate the ABLs across environments. Thirteen ABLs exhibited ramulosis resistance. Fourteen ABLs were classed as susceptible cultivars, while the remaining 30 exhibited intermediate levels of resistance. Half of the individuals in susceptible ABLs exhibited dwarfism symptoms while the plant population in resistant cultivars showed lower percentage of dwarfism (<1%) and sprouting (around 50%). Thirty seven ABLs representing the range of disease responses were evaluated at a second location. Multifactor ANOVA revealed that resistance measured as RSC scores can be used to evaluate genotypes across environments to identify sources of resistance. These resistant ABLs can be released as new resistant cultivars for the Caribbean or used as parents in breeding programs.

Correlations and path analysis in soybean progenies with resistance source to cyst nematode (race 3)

Path analysis is an important study that slices the correlation coefficients between two variables to evaluate whether the relationship between them is of cause and effect. This study aimed to estimate the phenotypic and genotypic correlations between agronomic traits and perform a path analysis in order to identify variables for indirect selection aiming at a higher grain yield. Fourteen soybean F6 lines from the soybean breeding program of FCAV–UNESP, Jaboticabal, São Paulo, Brazil, were analyzed. The experimental design was a randomized block design with three replications. The agronomic traits plant height at maturity (PHM), first pod height (FPH), lodging (Ld), agronomic value (AV), number of pods per plant (NP), number of seeds per plant (NS), and grain yield (GY) were evaluated. Overall, the genotypic correlations were higher than their corresponding phenotypic correlations. The genotypic correlations between grain yield and the traits agronomic value, number of pods per plant, and number of seeds per plant were positive, significant, and of high magnitude. Path analysis showed that the trait number of seeds per plant had the highest direct effect on grain yield, while the trait number of pods per plant had the highest indirect effect through the number of seeds per plant on grain yield

Predicting Genetic Variance from Genomewide Marker Effects Estimated from a Diverse Panel of Maize Inbreds

Predicting the genetic variance (VG) in a biparental population has been difficult. Our objective was to determine whether the population mean, VG, and mean of the top 10% of progeny in a cross can be predicted effectively from genomewide marker effects estimated from a diverse panel of inbreds. Eight maize (Zea mays L.) crosses that differed in their predicted mean and VG were evaluated for plant and ear height and growing degree days to silking. Each cross was represented by 120 to 144 random F3 lines that were evaluated in balanced experiments at three locations in Minnesota in 2017. Correlations between the observed and predicted means of each breeding population were significant (r ≥ 0.80, P = 0.05) for all three traits. However, correlations between the observed and predicted VG were nonsignificant (−0.24 to 0.14) for the three traits. Correlations between the observed and predicted mean of the top 10% of progeny in each cross were significant (P = 0.05) for plant height (0.72), but not for ear height and silking date. These results for predicting the mean of the top 10% of progeny reflected the ability to predict the mean but not VG. We concluded that the mean, but not the VG, of biparental crosses can be effectively predicted from genomewide marker effects estimated from a diverse panel of inbreds.

Genetic variation and development of a SCAR marker of anemone-type flower in chrysanthemum

An anemone shape featuring elongated and pigmented disk florets is an important target in breeding for flower shape in chrysanthemum. A good understanding of the inheritance of anemone-related traits and specific molecular markers are vital for accelerating the breeding progress. In this study, two segregating intercultivar F1 populations of the anemone-type ‘Nannong Xuefeng’ × the nonanemone-type ‘QX096’ (80 lines) and the same anemone-type ‘Nannong Xuefeng’ × ‘Monalisa’ (144 lines) were employed to investigate the genetic variation of anemone traits, and the anemone-specific markers were developed via the bulked segregant analysis (BSA) method by constructing two extreme bulks from each 10 anemone-type and nonanemone-type F1 lines, respectively. A moderate high level of variation coefficient (~ 24 to 57%) was obtained for most tubular floret traits relevant to the anemone type in both segregating populations. The anemone morphology of the hybrids was intermediate between that of their parents, and some transgressive individuals were observed, indicating great potential for the selection of lines with the desirable anemone type. In the BSA, four sequence-related amplified polymorphism (SRAP) primer combinations were identified as informative between the bulks of the anemone and nonanemone F1 individuals. After cloning and sequencing, only one SRAP marker, i.e., M11E1_272, was successfully converted to the sequence-characterized amplified region (SCAR) marker SCAR168. The SCAR marker was validation in the two F1 populations demonstrated that the marker SCAR168 could truly discriminate anemone and nonanemone types with a high coincidence ratio 87.86~92.5%. In addition, a general linear model (GLM)-based association analysis (P < 0.01) revealed that the SCAR marker exhibited a positive effect on the anemone traits and explained 20.83~33.66% phenotypic variation. Results of the current study show the inheritance pattern of anemone traits, and the developed anemone-specific SCAR marker paves the way for the marker-assisted selection of flower shape in chrysanthemum.

Selection in Base Population of Ornamental Peppers (Capsicum annuum L.)

Aims: The aim of this study was to characterize and select plants with ornamental potential and resistant to pathogens in generation F2.&#x0D; Study Design: For genetic divergence analysis, Tocher's grouping method was used, based on the standardized Euclidean distance. Analyses were carried out for the quantitative and qualitative data separately and also for the data together. In addition, the relative importance of the characteristics evaluated for genetic divergence was calculated using SINGH's Methodology (1981). All analyses were performed using the computational Genes program.&#x0D; Place and Duration of Study: The experiment was conducted in a greenhouse of the Plant Biotechnology Laboratory of the Center of Agrarian Sciences (CCA) of the Federal University of Paraíba (UFPB). The treatments consisted of 354 progenies, an F2 generation of ornamental peppers (Capsicum annuum L), belonging to the Germplasm Bank of UFPB, derived from the controlled self-fertilization of F1 and obtained from the crossing between the parents UFPB390 X UFPB137. Plants grown in vessels of 900 mL filled with commercial substrate. There was variability among genotypes for the evaluated characters.&#x0D; Methodology: Genotypes were characterized according to the descriptors for Capsicum suggested by IPGRI. 20 quantitative characters and 4 qualitative in ornamental peppers were evaluated. Leaves identified from an optical microscope using the illustrated descriptor of imperfect fungus.&#x0D; Results: The variability between genotypes was higher for qualitative characters related to disease resistance. It is possible to select individual plants for opening lines in Generation F3. 7 plants; 7; 15; 50; 69; 120; 155; 157; 196; 314; 326; 331; 347 should be selected for not presenting symptoms of fungi diseases.&#x0D; Conclusion: Greater diversity among genotypes was detected when the incidence of diseases in the plants was evaluated. The plants 7; 15; 50; 69; 120; 155; 157; 196; 314; 326; 331; 347 should be selected because they do not present symptoms of fungal diseases.

Identification of a locus for seed shattering in rice (Oryza sativa L.) by combining bulked segregant analysis with whole-genome sequencing

Seed shattering is an important trait related to the efficiency of harvesting seeds in crops. Although several genes have been identified to control seed shattering in rice (Oryza sativa L.), the genetic architecture underlying extensive variation of seed shattering is yet unclear. ‘Oonari’, a moderate-shattering indica rice cultivar, was developed from a mutant obtained through gamma-ray irradiation of an easy-shattering cultivar ‘Takanari’. The grain pedicel of ‘Oonari’ showed greater resistance to bending than that of ‘Takanari’, while there were no obvious differences in resistance to pulling and abscission zone formation. Investigation of the seed shattering of an F2 population from a cross between ‘Takanari’ and ‘Oonari’ indicated a single semi-dominant locus responsible for seed shattering, which was designated as Sh13. We used bulked DNA of F3 lines with the same shattering degree as that of ‘Oonari’ and DNAs of their parents for whole-genome sequencing, localizing Sh13 at the terminal region on the long arm of chromosome 2. In the candidate genomic region of ‘Oonari’, we identified a tandem duplicated segment containing a microRNA gene, osa-mir172d, whose wheat ortholog is involved in controlling grain threshability. Quantitative RT-PCR analysis indicated that the relative expression of osa-mir172d in ‘Oonari’ was twofold higher than that in ‘Takanari’. We suppose that the duplication of osa-mir172d be involved in reducing seed shattering in ‘Oonari’.

Evidences of organic acids exudation in aluminium stress responses of two Madeiran wheat (Triticum aestivum L.) landraces

Two wheat (Triticum aestivum L.) Madeiran landraces were subjected to 100 μM and 200 μM of aluminium (Al) in hydroponic culture, assessing the organic acid exudation role in plant’s responses to this metal. Samples of initial landrace populations (F0), F3 and haplodiploid lines (DH) were evaluated using standard tests: eriochrome cyanine R staining, root elongation and callose accumulation in roots. Root exudates were obtained to determine if the accumulation of malic and citric acids in hydroponic medium was a response to Al exposure. Additionally, the presence of ALMT1 gene was determined using five microsatellite markers. Standard tests confirmed that ISOP 76 was Al tolerant and ISOP 239, Al susceptible. ISOP 76, in the presence of 100 μM Al, exuded substantially more malic acid (12.87 to 43.33 mg/L), than ISOP 239 (3.65 to 7.72 mg/L). The levels of both organic acid exudation were substantially lower in ISOP 239 than in the ISOP 76. In the presence of 200 μM Al, ISOP 76 F0 shows a higher root elongation ratio (better tolerates Al), but the DH line was the one that exuded higher content of malic acid. Different gene alleles and promoters were detected in both landraces. Molecular differences could explain the observed dissimilarity in organic acid exudation response to Al stress.

Genetic Parameter Evaluation on Advanced Generations of A Cross to Improve Magelang Local Black Rice Cultivars

Evaluating genetic selection parameters of a cross between a local blackgrained rice cultivar from Magelang and an improved rice cultivar ‘Situbagendit’ is necessary to check the efffectiveness of selection in advanced generations, i.e. F4, F5 and F6 generation. The objective of this study was to compare and evaluate changing in several genetic parameters of the generations so that we can assess the selection effectiveness. Randomly picked 48 lines of F4, F5 and F6 generation, respectively, along with their parents, were evaluated on a farmer’s field in Pakem, Yogyakarta from May until September 2016. The experiment was arranged in an incomplete randomized design with two replications. Seed of each F4, F5 and F6 lines with their parents were planted in 1 m × 2 m plot, with 20 cm × 20 cm plant spacing. For each plot 40 individuals were planted. The agronomic characters were evaluated: plant height, productive tillers, pericarp color, full grains, empty grains, weight of 1000 seeds, days to flowering and days to maturing. Genetic variances, heritability and expected genetic gain among and within family from the advanced generations were evaluated and compared. Results showed that heritability and genetic gains value whether from selected or unselected generation need more emphasis on within family selection especially in generative (full grains, empty grains and weight of 1000 seed) characters.

RNA editing analysis of ATP synthase genes in the cotton cytoplasmic male sterile line H276A

BackgroundPollen development is an energy-consuming process that particularly occurs during meiosis. Low levels of adenosine triphosphate (ATP) may cause cell death, resulting in CMS (cytoplasmic male sterility). DNA sequence differences in ATP synthase genes have been revealed between the N- and S-cytoplasms in the cotton CMS system. However, very few data are available at the RNA level. In this study, we compared five ATP synthase genes in the H276A, H276B and fertile F1 (H276A/H268) lines using RNA editing, RNA blotting and quantitative real time-PCR (qRT-PCR) to explore their contribution to CMS. A molecular marker for identifying male sterile cytoplasm (MSC) was also developed.ResultsRNA blotting revealed the absence of any novel orf for the ATP synthase gene sequence in the three lines. Forty-one RNA editing sites were identified in the coding sequences. RNA editing showed that proteins had 32.43% higher hydrophobicity and that 39.02% of RNA editing sites had proline converted to leucine. Two new stop codons were detected in atp6 and atp9 by RNA editing. Real-time qRT-PCR data showed that the atp1, atp6, atp8, and atp9 genes had substantially lower expression levels in H276A compared with those in H276B. By contrast, the expression levels of all five genes were increased in F1 (H276A/H268). Moreover, a molecular marker based on a 6-bp deletion upstream of atp8 in H276A was developed to identify male sterile cytoplasm (MSC) in cotton.ConclusionsOur data substantially contributes to the understanding of the function of ATP synthase genes in cotton CMS. Therefore, we suggest that ATP synthase genes might be an indirect cause of cotton CMS. Further research is needed to investigate the relationship among ATP synthase genes in cotton CMS.