F3 Lines Research Articles

Identification of a Locus for High-Temperature Adult-Plant Resistance to Stripe Rust in the Wheat Yr8 Near-Isogenic Line Through Mutagenesis and Molecular Mapping.

Aegilops species are wheat relatives that harbor valuable disease resistance genes for wheat breeding. The wheat Yr8 near-isogenic line AvSYr8NIL has long been believed to carry only Yr8 for race-specific all-stage resistance to stripe rust, caused by Puccinia striiformis f. sp. tritici, derived from Aegilops comosa. However, AvSYr8NIL has been found to have high-temperature adult-plant (HTAP) resistance in our field and greenhouse tests. To confirm both HTAP and Yr8 resistance, seeds from AvSYr8NIL were treated with ethyl methanesulfonate to generate mutant lines. The mutant lines with only Yr8 (M641) and only HTAP resistance (M488) were crossed with the susceptible recurrent parent Avocet S (AvS). The F1 and F4 lines of AvS/M641 were phenotyped with Yr8-avirulent races in the seedling stage at the low-temperature (4 to 20°C) profile, while the F1, F2, F4, and F5 lines of AvS/M488 were phenotyped with Yr8-virulent races in the adult-plant stage at the high-temperature (10 to 30°C) profile. Both Yr8 and the HTAP resistance gene (YrM488) were recessive. The F4 populations of AvS/M641 and AvS/M488 were genotyped using polymorphic Kompetitive allele-specific PCR markers converted from single-nucleotide polymorphisms. Yr8 was mapped to a 0.66-cM fragment, and YrM488 was mapped to a 1.22-cM interval on chromosome 2D. The physical distance between the two resistance genes was estimated to be more than 500 Mb, indicating their distinct loci. The mutant lines with separated resistance genes would be useful in enhancing our understanding of different types of resistance and in further studying the interactions between wheat and the stripe rust pathogen.

Breeding of high seed oil oleate levels into Upland cotton from wild Gossypium barbadense L. germplasm

AbstractA high seed oil oleate trait identified in wild Gossypium barbadense L. cotton accession GB713 (PI 608139) was bred into Upland cotton (Gossypium hirsutum L.) cultivar Sure‐Grow 747 (SG747, PVP 9800118). Starting from the F2 generation of an initial cross between GB713 and SG747, plants were selected by measuring the seed oil fatty acid distributions by gas chromatography. Selected F3 plants were crossed to M Rk‐Rn 6, a line previously created from GB713 and SG747 for improved nematode resistance. High‐oleate plants were selected in the F2 population. Selected plants were then crossed to HOa1 (a ∼35% oleate line derived from M Rk‐Rn 1, a sibling line to M Rk‐Rn 6), and high‐oleate plants were again selected in the F2 population. F3 plants were re‐selected for the high‐oleate trait, and four selected F4 lines were evaluated in 2022 field plots. The four lines had oleate levels between 52% and 57%, approximately triple that found in normal cottonseed oil (15%–19%) and higher than in either the high‐oleate wild GB713 parent (∼40%) or in the previously released HOa cotton plant lines (33%–35%). The increased oleate levels occurred with an approximately equal reduction in linoleic acid. Other seed and fiber properties were largely like those of SG747, although some residual GB713 character existed within the lines. The resulting oil composition should be ideal for use in deep fat frying, with the high level of oleic acid improving the oil's oxidative stability but with sufficient linoleic acid to maintain frying flavor.

The interactions of Rht15 and Rht1 alleviate some of their negative effects on agronomic traits in durum wheat

The application of dwarfing genes in wheat breeding effectively reduced plant height, improved lodging resistance and increased the harvest index. Although the gibberellin-responsive (GAR) dwarf gene Rht15 did not negatively affect coleoptile length or root traits while reducing the plant height, it reduced the yield plant−1. The gibberellin-insensitive (GAI) dwarf gene Rht1 can increase wheat yield under favorable conditions, but it reduces coleoptile length and affects root traits. This study was conducted to investigate whether the interaction of Rht15 and Rht1 can alleviate their negative effects. To analyze the interaction of Rht15 and Rht1, field experiments were conducted with the F5, F6 and F7 lines of the four genotypes, Rht15+Rht1, Rht15, Rht1 and tall lines detected using Rht15 and Rht1 molecular markers, derived from Durox (Rht15) and Kronos (Rht1), by comparing their effects on seedling traits, plant height and internode length, lodging resistance, flag leaf, yield and quality traits in durum wheat. The results showed that although the interaction of Rht15 and Rht1 did not overcome the inhibitory effect of Rht1 on coleoptile growth, it alleviated the negative effect of Rht1 on maximum root length (+14.8%). The grain yield plant−1 (+7.2%) of the Rht15 lines was improved under the action of Rht1 but was still lower than that of the Rht1 lines (−12.7%). The Rht15+Rht1 lines had the strongest effect on reducing plant height and center of gravity height (−42.2% and −41.5%), which significantly improved lodging resistance (+175%). The flag leaf area (+97.4%) and SPAD value (+11.6%, +9.6% and +10.6%) were also significantly increased. In addition, the coleoptile length of the Rht15 lines was not significantly different from that of the tall lines, the plant height and center of gravity height were significantly reduced (−30.5% and −34.0%), and the lodging resistance was significantly increased (+176.8%). The Rht1 lines had increased grain yield (+12.7%) due to an increased 1000-kernel weight (+12.9%) compared to the tall lines. In conclusion, the combination of Rht15 and Rht1 alleles enhanced the advantages and partially alleviated the defects in some traits when compared to the individual alleles, but the grain yield plant−1 was still lower than the Rht1 lines. This reflected the limitations of Rht15, and further confirmed the yield advantages of Rht1.

Genomics and Physiology of Chlorophyll Fluorescence Parameters in Hordeum vulgare L. under Drought and Salt Stresses.

To map the genomic regions and control chlorophyll fluorescence attributes under normal, salinity-, and drought-stress conditions in barley (Hordeum vulgare L.) at the seedling stage, an experiment was conducted in 2019-2020 using 106 F8 lines resulting from the cross between Badia × Kavir. Initially, the different chlorophyll fluorescence parameters were evaluated. Under drought stress, the highest decrease was related to REo/CSm (59.56%), and the highest increase was related to dV/dto (77.17%). Also, under salinity stress, the highest decrease was related to Fv/Fo (59.56%), and the highest increase was related to DIo/RC (77.17%). Linkage maps were prepared using 152 SSR polymorphic markers, 72 ISSR alleles, 7 IRAP alleles, 29 CAAT alleles, 27 Scot alleles, and 15 iPBS alleles. The obtained map accounted for 999.2 centi-Morgans (cM) of the barley genome length (92% of the whole barley genome). The results indicated the importance of chromosomes 3, 2, and 7 in controlling ABS/CSm, Area, ETo/CSm, Fm, Fv, and ETo/RC under drought stress. qEToRCD-7, as a major QTL, controlled 18.3% of ETo/RC phenotypic variation under drought stress. Under salinity stress, the regions of chromosomes 2 and 7 (102 cM and 126 cM) controlled the parameters ABS/CSo, Fm, Fo, Fv, TRo/SCo, Area, ETo/CSm, and ETo/CSo. The results showed that chlorophyll fluorescence is an important parameter in the study of drought and salinity effects on barley. This is the first report of the investigation of changes in the genetic structure of quantitative genes controlling the fluorescence parameters associated with barley response to drought and salinity stresses in the Iranian barley RILs population. According to the obtained results, it is possible to use HVPLASC1B and EBmac0713 in normal conditions, ISSR21-2 and ISSR30-4 in drought conditions, and Bmac0047, Scot5-B, CAAT6-C, and ISSR30iPBS2076-4 in saline stress conditions to select genotypes with higher photosynthetic capacity in marker-assisted selection programs.

Identification of a novel locus C2 controlling canary yellow flesh color in watermelons.

The flesh color of watermelon is an important trait that is determined by carotenoid composition and affects consumers' fruit desirability. Although a complete dominant control by C locus (Cllcyb) for canary yellow flesh (CY) over red flesh has been reported, red and CY colors frequently appear as a mixed pattern in the same flesh (incomplete canary yellow, ICY) in F1 and inbred lines carrying dominant C alleles. Therefore, we examined the genetic control of the mixed color pattern in ICY using whole-genome resequencing of three ICY (ICY group) and three CY inbred lines (CY group), as well as genetic linkage mapping of an F2 population. The segregation pattern in 135 F2 plants indicated that CY is controlled by a single locus (named C 2) dominant over ICY. The whole-genome resequencing of ICY and CY inbred lines revealed an ICY/CY-specific region of approximately 27.60-27.88Mb on Chr. 2 that was polymorphic between the ICY and CY groups. Our genetic map, using nine cleaved amplified polymorphic sequence markers developed based on the single-nucleotide polymorphisms from the ICY/CY-specific region, confirmed that C 2 is located on Chr. 2 and cosegregated with the marker (M7) derived from a non-synonymous single-nucleotide polymorphism of the pentatricopeptide repeat (PPR) gene (ClPPR, Cla97C02G039880). Additionally, 27 watermelon inbred lines of ICY, CY, and red flesh were evaluated using previously reported Cllcyb (C locus)-based markers and our C 2 locus-linked ClPPR-based marker (M7). As a result, dominant alleles at the C 2 locus were required to produce CY, in addition to dominant alleles at the C locus, while a recessive homozygous genotype at the C locus gave the red flesh irrespective of the genotype at the C 2 locus. Using a ClPPR-based cleaved amplified polymorphic sequence developed in this study and Cllcyb-based markers, watermelon cultivars with CY, ICY, and red flesh could be successfully discerned, implying that the combined use of these markers will be efficient for marker-assisted selection of flesh color in watermelon breeding.

Influence of alleles of the Ppd-D1 gene and different duration of requirement in yarovization on economic valuable signs of winter bread wheat

Aim. To determine the influence of alternative alleles of the Ppd-D1 gene and phenotypic differences in the duration of the need for vernalization and their interaction on earing time and grain yield of recombinant lines of bread winter wheat. Methods. Growing plants in the field and on the vegetation site, PCR with specific primers for Ppd-D1 and Ppd-B1c genes, phenological observations, artificial vernalization, statistical analysis. Results. 136 recombinant F7 lines from crossing [F1 (Chaika//Cappelle Desperez/2В Chinese Spring) / Kharkivska 81] F2 / Obryi identified by alleles of the Ppd-D1 gene, characterized by the duration of the need for vernalization, duration of the period to earing, plant height, weight 1000 grains and grain harvest. Conclusions. Genotypes with the presence of the Ppd-D1a allele eared 2.9 days earlier than those with the Ppd-B1b allele, and the lines with a 30-day need – one day earlier than those with a 40-day need for vernalization. Different combinations of alternative alleles of the Ppd-D1 gene and characteristics of the lines regarding the need for vernalization significantly influenced the differences in the duration of the period before heading and the weight of 1000 grains. Among the lines that significantly exceeded the control varieties Antonivka and Kuyalnik in terms of yield, those with a different combination of two traits were found, but the share of lines with a combination of the Ppd-D1a gene and 30 daily need for vernalization was greater and they formed the largest yield.

Genetic trends and multivariate interrelationships for grain quality of irrigated rice genotypes

For genetic improvement programs, researches with multivariate approaches in rice are fundamental, to define genetic trends, clusters and correlations of agronomic characters that together help selection procedures. This work aimed to reveal the agronomic performance, trends and genetic interrelationships of grain quality based on multivariate models applied to elite lines of irrigated rice. The experiment took place in the 2017/2018 harvest, held at Estação Experimental Terras Baixas (ETB), of Embrapa Clima Temperado. The study used randomized blocks design, with three replications. There were fifteen F6 lines and four control cultivars. Evaluation of intrinsic physical quality attributes with the aid of S21 grain statistical analyzer, as well as grain yield and mill yield (whole and broken grains). Performance of analysis of variance, genetic parameters and Scott Knott cluster test, linear correlation, canonical correlations, cluster analysis via generalized Mahalanobis distance, using the Toucher method, in addition to BIPLOT principal component analysis. The results showed that PH18502 and PH18701 strains presented better agronomic performance for the studied characters, by univariate analysis. The linear and canonical correlations presented demonstrate potential in the direction of selection of multiple characters and point to the possibility of indirect selection among the relevant agronomic characters for the production chain of irrigated rice.

Karakter Morfologi dan Depresi Silang dalam Galur F4 Jagung Ungu Hasil Persilangan Bersari Bebas

<p>Breeding of corn plants resulting from crosses experienced problems with inbreeding depression. Inbreeding depression can cause a decrease of good characters in maize lines. Information about inbreeding depression needs to be known so that it does not appear in the maize lines. This research aims to determine the presence of inbreeding depression in purple corn lines from open pollinated and to determine the morphological character as a selection criterion for the F4 lines. Research using experimental methods. Plant selection was carried out using the ear-to-row method. Isolation of plants using distance and time of planting method. Observation of morphological characters using Royal Horticultural Society (RHS) Color Charts and the inbreeding depression test. F4 lines has inbreeding depression on the characters of plant height, stem diameter, number of leaves, male flowering age, female flowering age, cob length, cob weight with husk, cob weight without husk, and weight of 100 seeds . The F4 lines of corn plants that did not experience inbreeding depression on plant height and stem diameter characters in lines F<sub>4</sub>-PxU-11-25-18 and F4-PxU-11-25-25. Characters that can be used in the selection of F5 generation corn lines are plant height, stem diameter, cob length, cob weight with husk, cob weight without husk, and weight of 100 seeds. These characters can be used as selection criteria for the next generation.</p>

Using Chromosomal Abnormalities and Germination Traits for the Assessment of Tritipyrum Amphiploid Lines under Seed-Aging and Germination Priming Treatments

Primary Trans Chromosomal Tritipyrum (PTCT) amphiploid is a new cereal grown in saline soil and brackish water for grain and forage production. We evaluated the tolerance to seed deterioration in 13 promising PTCT lines, assessing accelerated aging (AA) tests by using AA boxes with 100% relative humidity at 40 °C for 72 h. The (Ma/b)(Cr/b)F4 and (St/b)(Cr/b)F4) PTCT lines, more sensitive to seed aging, were primed with NaCl, Salicylic Acid (SA), and Polyethylene Glycol (PEG) to increase the seed vigor of artificially aged seeds. Germination and emergence traits, biochemical parameters, and chromosomal abnormalities induced by artificial aging were measured in deteriorated and not-deteriorated seeds. The highest reduction percentages related to seed vigor were observed in (Ka/b)(Cr/b)F2 (34.52) and La(4B,4D)/b (28.15) lines, while the lowest was found in (Ma/b)(Cr/b)F4 (7.65) and (St/b)(Cr/b)F4 (7.46) lines. Seed aging also increases electrolytes, potassium, and protein leakages. Chromosomal abnormalities are caused by seed aging that interferes with chromosome behaviors during cell division. Seed priming on aged seeds revealed an increase in the germination percentage (GP) with PEG treatment, while the priming by SA showed an increase in seedling traits, such as the seedling length (SL2). In conclusion, we highlighted the potential use of different PTCT lines and the effective use of seed priming on deteriorated seed to enhance seed viability and seedling vigor as a useful tool for sustainable agriculture.

Construction of a high-density genetic linkage map and QTL mapping for bioenergy-related traits in sweet sorghum [Sorghum bicolor (L.) Moench

Sorghum is an important but arguably undervalued cereal crop, grown in large areas in Asia and Africa due to its natural resilience to drought and heat. There is growing demand for sweet sorghum as a source of bioethanol as well as food and feed. The improvement of bioenergy-related traits directly affects bioethanol production from sweet sorghum; therefore, understanding the genetic basis of these traits would enable new cultivars to be developed for bioenergy production. In order to reveal the genetic architecture behind bioenergy-related traits, we generated an F2 population from a cross between sweet sorghum cv. 'Erdurmus' and grain sorghum cv. 'Ogretmenoglu'. This was used to construct a genetic map from SNPs discovered by double-digest restriction-site associated DNA sequencing (ddRAD-seq). F3 lines derived from each F2 individual were phenotyped for bioenergy-related traits in two different locations and their genotypes were analyzed with the SNPs to identify QTL regions. On chromosomes 1, 7, and 9, three major plant height (PH) QTLs (qPH1.1, qPH7.1, and qPH9.1) were identified, with phenotypic variation explained (PVE) ranging from 10.8 to 34.8%. One major QTL (qPJ6.1) on chromosome 6 was associated with the plant juice trait (PJ) and explained 35.2% of its phenotypic variation. For fresh biomass weight (FBW), four major QTLs (qFBW1.1, qFBW6.1, qFBW7.1, and qFBW9.1) were determined on chromosomes 1, 6, 7, and 9, which explained 12.3, 14.5, 10.6, and 11.9% of the phenotypic variation, respectively. Moreover, two minor QTLs (qBX3.1 and qBX7.1) of Brix (BX) were mapped on chromosomes 3 and 7, explaining 8.6 and 9.7% of the phenotypic variation, respectively. The QTLs in two clusters (qPH7.1/qBX7.1 and qPH7.1/qFBW7.1) overlapped for PH, FBW and BX. The QTL, qFBW6.1, has not been previously reported. In addition, eight SNPs were converted into cleaved amplified polymorphic sequences (CAPS) markers, which can be easily detected by agarose gel electrophoresis. These QTLs and molecular markers can be used for pyramiding and marker-assisted selection studies in sorghum, to develop advanced lines that include desirable bioenergy-related traits.

Agronomic performance and correlation of growth components, yield components and production on 30 F3 lines of new plant type of black rice specific to highland ecosystems

Many high-yielding varieties of rice have been released, but generally lack good quality. This study aimed to examine the agronomic performance of several new plant types of black F3 rice lines at two medium altitude. The research was carried out on rice fields in Tallunglipu District, North Toraja Regency with an altitude of 850 m above sea level. This research took place from May 2020 to November 2022. This study used the Single Seed Descend selection method which was arranged in randomized block design pattern at each location. The genetic material tested consisted of 30 F3 lines resulting from two combinations of crosses between Toraja local black rice, each of which was crossed with a national superior variety and 3 comparison varieties, namely Pare Ambo, Pare Lallodo and Inpari 4 which were repeated 3 times. The observational data were analyzed for variance and if there was a significant effect, then the Honestly Significant Difference was 5% and the value of closeness between characters was tested for correlation and weighted analysis (WINDEX) was performed to select the strains. The results showed that the character had a close correlation with productivity, namely the character of the weight of pithy grain per clump, the maximum number of tillers and the number of pithy grain per panicle. The lines with the best productivity were F3UKIT104-2-194 (5.7 tons/ha) and F3UKIT104-2-197 (5.4 tons/ha). The selected strains based on Windex selection are UKIT104-2-197, UKIT 104-2-194, UKIT 104-2-298, UKIT 104-2-089, UKIT 104-2-127, UKIT-101-2-131, UKIT-101-2-218, UKIT 104-2-003, UKIT 104-2-148, UKIT-101-2-002, UKIT-101-2-003, UKIT-104-2-046, UKIT 104-2-064, and UKIT 104-2-001.

Identification of novel sex determination loci in Japanese weedy melon

Japanese weedy melon exhibits unique sex expression with interactions between previously reported sex determination genes and two novel loci. Sex expression contributes to fruit quality and yield in the Cucurbitaceae. In melon, orchestrated regulation by sex determination genes explains the mechanism of sex expression, resulting in a great variety of sexual morphologies. In this study, we examined the Japanese weedy melon UT1, which does not follow the reported model of sex expression. We conducted QTL analysis using F2 plants for flower sex on the main stem and the lateral branch and mapped "occurrence of pistil-bearing flower on the main stem" locus on Chr. 3 (Opbf3.1) and "type of pistil-bearing flower" (female or bisexual) loci on Chr. 2 (tpbf2.1) and Chr. 8 (tpbf8.1). The Opbf3.1 included the known sex determination gene CmACS11. Sequence comparison of CmACS11 between parental lines revealed three nonsynonymous SNPs. A CAPS marker developed from one of the SNPs was closely linked to the occurrence of pistil-bearing flowers on the main stem in two F2 populations with different genetic backgrounds. The UT1 allele on Opbf3.1 was dominant in F1 lines from crosses between UT1 and diverse cultivars and breeding lines. This study suggests that Opbf3.1 and tpbf8.1 may promote the development of pistil and stamen primordia by inhibiting CmWIP1 and CmACS-7 functions, respectively, making the UT1 plants hermaphrodite. The results of this study provide new insights into the molecular mechanisms of sex determination in melons and considerations for the application of femaleness in melon breeding.

Interpreting the magnetic signatures and radiometric indicators within Kogi State, Nigeria for economic resources

The mineral and geothermal potentials of part of Kogi State was investigated through the interpretation of aeromagnetic and radiometric data of the study area. The analysis targeted bridging the gap of insufficient geophysical information of sub-crustal resources that could be of economic value within the area of study. Vertical derivatives, analytical signal and spectral depth analysis were used for the interpretation of the aeromagnetic data while the concentration and ternary images of the three radiogenic elements were used for the interpretation of the radiometric data. The result of first vertical derivative was helpful in delineating mineral potent lineaments labelled F1 to F8. The lineaments were seen trending E-W and NE-SW direction. A principal fault line F6 tends to separate the regions of sediments to the south-east and basement geologic formations to the south-western regions. Result of the analytical signal amplitude revealed regions with shallow intrusive magnetic rocks having high amplitudes ranging from 0.152 to 0.557 nT/m, while regions with magnetic rock intruding into sedimentary formations at greater depths, have medium to low amplitudes ranging from 0.014 to 0.136 nT/m. Regions delineated to be altered through hydrothermal process coincided with areas of major magnetic lineaments. The lineaments which could be fractures, faults or shear zones usually serve as conduits for mineral deposits during hydrothermal process. Result of potassium_thorium ratio map showed evidence of hydrothermal alteration in the NW and SW regions of study area. These regions of alterations also corresponds to regions where major lineaments were mapped and thus represent regions with significant potency for mineralisation. Result of spectral depth analysis on the aeromagnetic data showed that peak values of geothermal gradient and Heat flow were 27°C/km and 68 mW/m2 respectively, the values were recorded at the North-eastern part of study area, at the lower end of Koton-Karfe and part of Lokoja where the shallowest Curie point depth of 24 km also occurred. The estimated values of heat flow falls below the range of 80 to 100 mW/m2 recommended as threshold for a good source of geothermal energy, hence the region will not be prospectively good for a cost effective geothermal energy exploration. In order to assess the heat production within the study area due to activities of radioelements, a comparative analysis of the concentration of the three radiogenic elements was carried out. A relatively high radiogenic heat production (RHP) value of 3.4 μW/m3 was recorded at the North-western region indicating high occurrence of radioactivity within the granitic rocks. The (RHP) value of 3.4 μW/m3 is slightly below 4.0 μW/m3 which is a recommended value for a good source of geothermal energy.

Mapping and characterization of the recessive leaf rust resistance gene Lr83 on wheat chromosome arm 1DS

The leaf rust resistance gene in Thatcher wheat derivative 78-1 was mapped to chromosome 1DS with SNP markers and designated as Lr83. 'Thatcher' wheat near isogenic line RL6149, a putative derivative of Triticum dicoccoides, was previously determined to carry leaf rust resistance gene Lr64 on chromosome arm 6AL and a second gene temporarily named LrX on chromosome arm 1DS. The objective of this study was to map and characterize LrX in a population of recombinant inbred lines (RILs) that segregated for a single gene. Thatcher line 78-1 with LrX was crossed with Thatcher and individual F2 seedlings and F6 RILs were evaluated for leaf rust response. The 208 F2 plants segregated for a single recessive gene and 148 F6 lines for a single gene. The RILs and parents were characterized by genotyping by sequencing (GBS). Six GBS markers and five Kompetitive Allele-Specific PCR (KASP) markers were used to map LrX on the distal region of chromosome arm 1DS. LrX was 1 centiMorgan (cM) proximal to marker K-IWB38437 and 0.4cM distal to GBS marker 1D_9037138. Line 78-1 was crossed with Thatcher wheat lines with Lr21, Lr42, and Lr60 for allelism tests. LrX mapped 19.49cM from Lr21 and 11.93cM from Lr42. In the cross of line 78-1 with the Thatcher line with Lr60, one recombinant in 1,003 F2 plants was found. LrX and Lr60 are at tightly linked loci on the distal region of chromosome arm 1DS. The gene in line 78-1 was designated as Lr83. Cytological examination of RL6149 provided no evidence of transfer of a chromosome segment of an A- or B-genome chromosome to chromosome 1D.

Creation of New Oregano Genotypes with Different Terpene Chemotypes via Inter- and Intraspecific Hybridization.

Oregano is a medicinal and aromatic plant of value in the pharmaceutical, food, feed additive, and cosmetic industries. Oregano breeding is still in its infancy compared with traditional crops. In this study, we evaluated the phenotypes of 12 oregano genotypes and generated F1 progenies by hybridization. The density of leaf glandular secretory trichomes and the essential oil yield in the 12 oregano genotypes varied from 97-1017 per cm2 and 0.17-1.67%, respectively. These genotypes were divided into four terpene chemotypes: carvacrol-, thymol-, germacrene D/β-caryophyllene-, and linalool/β-ocimene-type. Based on phenotypic data and considering terpene chemotypes as the main breeding goal, six oregano hybrid combinations were performed. Simple sequence repeat (SSR) markers were developed based on unpublished whole-genome sequencing data of Origanum vulgare, and 64 codominant SSR primers were screened on the parents of the six oregano combinations. These codominant primers were used to determine the authenticity of 40 F1 lines, and 37 true hybrids were identified. These 37 F1 lines were divided into six terpene chemotypes: sabinene-, β-ocimene-, γ-terpinene-, thymol-, carvacrol-, and p-cymene-type, four of which (sabinene-, β-ocimene-, γ-terpinene-, and p-cymene-type) were novel (i.e., different from the chemotypes of parents). The terpene contents of 18 of the 37 F1 lines were higher than those of their parents. The above results lay a strong foundation for the creating of new germplasm resources, constructing of genetic linkage map, and mapping quantitative trait loci (QTLs) of key horticultural traits, and provide insights into the mechanism of terpenoid biosynthesis in oregano.

Identification of important morphology for waterlogging tolerance from developed mung bean F2 population

Waterlogging is severe abiotic stress during mung bean (Vigna radiata (L.) R. Wilczek var. radiata) production. Waterlogging impacts yield loss for the legume crop by around 40%-70%, depending on the severity and duration of the waterlogging. In total, 107 collected mung bean varieties were evaluated under managed waterlogging. The F2 population from crossing between waterlogging-tolerant and -susceptible mung bean varieties were screened under waterlogging conditions. Morphological responses to the waterlogging were recorded. Correlation and path coefficient analyses were used to identify essential traits for waterlogging tolerance and seed yield potential under water stress. Mung bean varieties in clusters 5 and 6 were high waterlogging tolerance with survival rates of 66.66% and 61.11%, respectively. Of 199 F2 lines from crossings between the Kamphaeng Sean2 and W162, 20 lines presented high waterlogging tolerance. The injury score was negatively correlated with the number of leaves at the final date of waterlogging (-0.845) and 1 wk after terminating the waterlogging (-0.885). At the final date of waterlogging condition, the number of leaves and leaf greenness stability index directly affected leaf injury at -0.5928 and -0.4385. One week after waterlogging termination, only the number of leaves affected the leaf injury at -0.8599. The number of leaves directly affected seed yield components at 0.6534 and higher than the direct effect of the other traits. Thus, the number of leaves was a suitable morphological parameter along with the injury score for selecting waterlogging tolerance. The number of leaves was a suitable parameter for selecting high seed yield potential under waterlogging conditions.

Combining datasets to routinely predict fusarium head blight resistance in a wheat breeding program

AbstractFusarium head blight (FHB; Fusarium graminearum Schwabe) is a devastating fungal disease of wheat (Triticum aestivum L.) that can significantly reduce yield and grain quality. Datasets from different stages of field evaluation can be combined into a training population to predict FHB resistance. Our objective was to determine if FHB resistance among F5 lines can be predicted accurately with historical lines, parental lines, and a subset of F5 lines. Lines at the F5 and preliminary yield trial (PYT) stages in the University of Minnesota wheat breeding program were evaluated in two locations from 2016 to 2020 and were genotyped with 3679 single nucleotide polymorphism markers. Historical datasets with 368 to 3015 lines had predictive abilities of −0.01 to 0.20, whereas F5 subsets had predictive abilities of 0.04–0.32. Adding subsets of F5 lines to the historical datasets led to incremental improvements in predictive abilities in most cases, especially when the subset was selected via the pedigree or k‐means approach. The most effective training populations were those that contained a subset of 200 F5 lines chosen via the k‐means method, the F5 parents, and the PYT lines tested in the same year, with predictive abilities that were usually higher than that of the F5 subset. We have started to use such combinations of datasets to routinely predict FHB resistance of F5 lines in our breeding program.

Molecular analysis of the F4 progenies obtained through pollen selection for heat tolerance in maize (Zea mays)

In the present study, three sets of F4 progeny lines developed through different cycles of pollen selection for heat tolerance were studied for the genetic differences using 16 SSR markers during 2017–20 at Department of Plant Biotechnology, University of Agricultural Sciences, Gandhi Krishi Vignana Kendra, Bengaluru, Karnataka. Three groups of F4 progenies used for the study are GGG (pollen selection for heat tolerance in F1, F2 and F3 generation); GCG (pollen selection for heat tolerance only in F1 and F3 generation); CCC (no pollen selection for heat tolerance in F1, F2 and F3 generation). Five randomly selected F4 lines of the cross of heat stress susceptible BTM4 and heat tolerant BTM6 represented each group. The three groups differed significantly for the number of male parent alleles as evidenced by SSR markers. The F4 (GGG) progenies had significantly more number of male parent type alleles compared to F4 (GCG) and F4 (CCC) lines. The F4 (CCC) lines recorded more number of female alleles compared to other F4 (GGG and GCG) lines. The effectiveness of pollen selection for heat tolerance towards increasing the frequency of male parent alleles and their transmission to the succeeding progenies has been demonstrated in the present study.

A new method for rapid screening of seed vigority of cereals

Seed deterioration is one of the major problems in agricultural production in arid and semi-arid regions. Seed deterioration reduces seed vigor and seedling establishment in the field. To introduce methods with sufficient sensitivity to more accurately determine the degree of grain deterioration, various methods have been developed under the conventional name of "vigor tests". This study aims to provide a rapid method for assessing seed vigor using the electrical conductivity test. The germination test and emergence test were performed in a completely randomized design with three replications. Treatments included the Tritipyrom line at 13 levels and seed deterioration at two levels. Germination percentage, emergence percentage, and electrical conductivity were significantly affected by seed deterioration. The highest electrical conductivity and the lowest electrical conductivity were respectively related to the lines of (Ka/b)(cr/b)F2 and (St/b)(Cr/b)F4. Although the lines are not significantly different in terms of germination and emergence percentage. Electrolyte leakage in aged seeds increased sharply in the first hours and then had a diminishing, after which it stopped and followed the logarithmic model, But the lines were different in terms of the slope of the first part of the graph (which was exponential).with its help, we can classify the lines or variety in terms of the amount of cell leakage, which indicates the amount of cell permeability. The highest (37.03) and lowest (29.01) slopes in the exponential part of the graph were related to the numbers (Ka/b)(cr/b)F2 and(St/b)(Cr/b)F4 line respectively. Therefore, by using a simple and quick four-hour electrical conductivity test, cultivars can be classified in terms of storage potential and early vigor.

Identification of novel and stable genomic regions associated with barley resistance to spot form net blotch disease under different temperature conditions during the reproductive stage

AbstractSpot form net blotch (SFNB) is one of the most important barley diseases in the world; abiotic stresses caused by climate change are also a problem for cultivation of cereals, including barley, on a global level. Identifying stable genomic regions associated with resistance to SFNB in different temperature conditions at the reproductive stage can accelerate the process of producing new cultivars resistant to this disease. In this study, 103 F8 lines, resulting from the cross of cultivars Kavir and Badia, were cultivated in three years on three different dates. After artificial inoculation with Pyrenophora teres f. maculata Gonbad Kavous isolate, the plants were evaluated at the adult stage. The planting dates were chosen so that during early, conventional and delayed planting dates, the reproductive stage of the lines coincided with cold, non‐thermal and heat stress conditions, respectively. A genome‐wide composite interval mapping method was used to identify quantitative trait loci (QTLs) controlling SFNB and estimate the effect of each of them. In the cold, non‐thermal and heat stress conditions at the reproductive stage, three (three major), four (two major) and six (one major) stable resistance QTLs against SFNB were detected, respectively. The stable QTLs of resistance including QRPtma‐2H, QRPtma‐3H and QRPtma‐7H were located on chromosomes 2H, 3H and 7H, respectively. After flanking markers confirm the resistance of QTLs to SFNB, the SCoT7‐C, ISJ17‐B and Bmac0144k markers can be used in the screening resistance of cultivars under non‐thermal and heat stress conditions. Moreover, the Bmac0282b and Ebmatc0016 markers can be used for screening resistance of cultivars under cold stress conditions in marker‐assisted selection projects.