Single Seed Descent Method Research Articles

Phenotypic Diversity of Root Characteristics in Recombinant Inbred Lines of Cross Between Lowland and Highland Rice Varieties for Drought Tolerance Potential.

<b>Background and Objective:</b> Breeding between highland and lowland rice varieties is one of the strategic breeding of lowland rice for enhancing drought-tolerant capacity through root structure improvement. The objective of this study was to evaluate the phenotypic diversity of rice root traits in pot screening compared to the lowland parent. <b>Materials and Methods:</b> The basket method was utilized in pot cultivation to evaluate the 100 of F7 Recombinant Inbred Lines (RILs) derived through single seed descent method from a cross between lowland rice, RD49 variety and upland rice, Payaleumgaeng (PLG) variety. The two parents and F7 progenies were evaluated for the number of shallow roots (SRN) and the number of deep roots (DRN), together with other traits which were the number of total roots (TRN), the Ratio of Deep Rooting (RDR), maximum Root Length (RL), Root Dry Weight (RDW), Shoot Dry Weight (SDW), the ratio of Root to Shoot Weight (RSR) and Plant Height (PH). <b>Results:</b> The result showed that PLG had significantly higher SRN, DRN, TRN and RDR than RD49. The distribution of these traits showed slightly positive skewness in DRN, RDR, RDW, SDW and RSR and negative skewness in SRN, TRN, RL and PH. However, some lines in this RIL population displayed better performance of root traits compared to both parents. Principal Component Analysis (PCA) of DRN, SRN, TRN and RDR in this population showed a distinctly different pattern among both parents. Most of the selected lines had superior RDR over RD49 and had various root characteristics patterns due to the diverse PCA coordinates. The yield trial of some breeding lines in this cross show superior yield over RD49 under drought-prone cultivation area. <b>Conclusion:</b> This study showed broad phenotypic diversity in the population constructed through single seed descent selection for enhancing deep root structure in rice for drought adaptation.

MAGIC lines in chickpea: development and exploitation of genetic diversity

In chickpea a multi-parent advanced generation intercross (MAGIC) population was developed using eight parents that are improved varieties and widely adaptable breeding lines. The main objective was to enhance the genetic diversity and bring novel alleles for developing superior chickpea varieties. The development scheme involved a sequence of 28 two-way, 14 four-way and 7 eight-way crosses, followed by bulking of final F1 plants. From F2 generation onwards single plants were grown as progenies and advanced to F8 by single seed descent method. The finally developed 1136 MAGIC lines were phenotyped under rainfed (RF) and irrigated (IR) conditions for 2 years (2013 and 2014) under normal season, and one year under heat stress (HS) condition (summer-2014) in field to estimate the genetic diversity created among these lines. Under RF-2014, RF-2013, IR-2014, IR-2013 and S-2014 seasons 46, 62, 83, 50 and 61 lines showed significantly higher grain yield than the best parent, respectively. Similarly, 23 and 19 common lines were identified under RF and IR conditions over two years and no common line was identified between RF/IR and HS conditions. Preliminary evaluation showed a large variation among MAGIC lines for flowering time (34–69 days), maturity (80–120 days), plant height (23.3–65 cm), grain yield (179–4554 kg/ha), harvest index (0.10–0.77) and 100 seed weight (10–45 g) under RF and IR conditions. Several genotypes with higher grain yield than the best check under heat stress were identified. These MAGIC lines provide a useful germplasm source with diverse allelic combinations to global chickpea community.

Combining ability studies for yield and related traits in soybean (Glycine max)

The present investigation was undertaken in F1 population of 36 crosses, obtained by crossing 18 inbred lines of soybean with two diverse testers in line × tester mating design during kharif 2012. All the parental lines and their F1 hybrids were evaluated in randomized complete block design at the Experimental Farm of Department of Crop Improvement, CSK HPKV, Palampur (HP ) during kharif 2013. The aim of this study was to identify suitable parents and hybrids for yield and its contributing traits. Experimental results revealed significant differences for lines, testers and line × tester for majority of the traits studied. Lines Bragg, Shivalik and P9-2-2 were found to be good general combiners for most of the traits. The cross combinations, Bragg × Hara Soya, DS-1213 × Hara Soya, H-330 × Hara Soya, PK-472 × Him Soya and H-330 × Him soya showed high per se performance and SCA effects for seed yield per plant and were rated as potential crosses for further improvement. Further, non-additive gene action (σD2) played a major role in the manifestation of almost all the traits which suggested the use of breeding approaches such as single seed descent method, reciprocal recurrent selection with one or two intermatings and diallel selective mating for the improvement of seed yield and related traits. Selection of parents based on their combining ability is an effective approach in hybrid breeding programme.

Genetic variability in the agronomic traits, inheritance pattern of seed coat colour and response to brown blotch disease among cowpea hybrids

Rapidity of improvement of cowpea cultivars often depends on the level of success achieved in the introgression of desirable gene(s) into varieties that are susceptible to biotic and abiotic stresses. This research work aimed at generating hybrids that possess resistant gene(s) to brown blotch disease as well as maintaining its brown seed coat, early maturing and high yield potentials. A mapping population was developed using single seed descent method of breeding between susceptible (Ife brown) and resistant (IT-95K-193-12) cowpea varieties to brown blotch disease. Hybrid seeds generated were inoculated with Colletotrichum truncatum and evaluated. A total of 356 crosses were made in direct (Ife brown × IT-95K-193-12) and reciprocal (IT-95K-193-12 × Ife brown) crosses. Only 8.43% percentage successful crosses were obtained. Seed coat colour was controlled by at least two genes and brown blotch was governed by maternal effect. Some of the hybrids generated possessed resistant gene(s) to brown blotch disease especially when IT-95K-193-12 was used as female parent and most of the hybrids were high yielding and early maturing especially among hybrids that originated when Ife brown was used as female parent.

New high-yielding conventional soybean adapted to the states of Goiás, Minas Gerais and Mato Grosso, Brazil

This paper aims to present the features of the new soybean cultivar UFUS Milionaria, which was developed by the Soybean Improvement Program of the Federal University of Uberlândia (UFU) through crossing between IAC-100 and Cristalina RCH cultivars, using the Single Seed Descent (SSD) method. UFUS Milionaria is resistant to many diseases caused by the fungus, bacteria, and virus. In addition, it also has been proved well-adapted to many Brazilian states, showing high yield even under water deficit conditions and Asian-rust infection; average yield was 4,451 kg ha -1 in 2015/16 growing season.

Positive Impact of Similarity on Twice Single Seed Descent of Purification on Bambara Groundnut (Vigna subterranea L. Verdcourt)

The main problem of local line Bambara groundnut ( Vigna subterranea L. Verdcourt) genotype improving is the low of purity. The research on genetic purification of Bambara groundnut had finished in twice single seed descent. The objective of this research was to find out the uniformity gain level within lines each other after single seed descent applied twice. This research was conducted in Agriculture Research Station, Universitas Brawijaya, from 2014 to 2016. There were 20 selected local lines evaluated twice with single seed descent method. On the first and second evaluation, it was applied on previous 19 local lines and 1 check genotype. Similarity coefficient was analyzed with cluster analysis of qualitative characters within lines. Variability within line was described on quantitative characters. The local lines had different response on single seed descent selection. These differences depended on genetic of qualitative characters. On the first single seed descent, it got similarity coefficient of 0.704-0.832. On the second one, it got similarity coefficient of 0.804-1.00. Increasing of similarity coefficient from 0.10-0.168 will improve purification of local lines 15.76-20.19 %. Two circles of single seed descent selection were capable to purify local lines. Variability of quantitative character depended on kind of character.

Kendali Genetik Karakter Morfologi dan Agronomi pada Tiga Populasi Sorgum (Sorghum bicolor (L.) Moench)

<p align="center"><strong>ABSTRACT</strong></p><p align="center"><strong> </strong></p>Sorghum is one of the potential foods with a higher protein content than rice. Sorghum seeds can be milled and cooked as sorghum rice. This study was aimed to obtain information on the inheritance of morphological and agronomic characters from the population derived from crosses of wide genetic background. The study consisted of the formation of F1 population and evaluation of morphological and agronomic characters in the segregated population (F2) of the three selected F1 genotypes. The location of the research was at IPB Experimental Field, Leuwikopo. The performance of the F1 genotypes were between the two parents, except for the yield components of PI-150-20-A x Numbu and PI-150-20-A x Kawali were higher than the parental lines. The performance of the F2 generation population was also between the parental lines, but with a wider distribution. The sorghum seed color is controlled not only by additive and dominant gene action, but also by epistatic gene action. The character of seed weight per panicle is controlled by epistatic gene action. In the F2 population of the crosses of PI-150-20-A x Numbu and PI-150-20-A x Kawali and PI-10-90-A x Numbu, the seed weight character is inherited with moderate heritability value. Based on genes action dan heritability, bulk or single seed descent method are suitable for yield improvement of the populations.<br /><br />Keywords: gene action, heritability, seed color, segregation, sorghum<br /><br /><br />

Research Article Selection of progenies of snap beans using mixed models (REML/BLUP)

The purpose of this research was to select the development of superior genotypes of snap beans adapted to edaphoclimatic conditions of the North and Northwest of Rio de Janeiro State, Brazil, applying the mixed model methodology. The test was installed and carried out in the experimental area of the Instituto Federal Fluminense (IFF), located in the municipality of Bom Jesus do Itabapoana, Rio de Janeiro State, Brazil, using the modified SSD (Single Seed Descent) method. The experiment was of randomized block design with three replications. We evaluated weight of pod per plant and number of pod per plant in ten progenies from the snap bean breeding program of the Universidade Estadual do Norte Fluminense (UENF); individual plants were assessed in each plot and in each replication (block). All progenies had mean productivity superior to 1 kg of pod per plant and 144 pods per plant. The 7 and 2 progenies, which came from the crossings between (UENF 7-5-1) L6 × L20 (UENF 14-3-3) and (UENF 7-5-1) L6 × L13 (UENF 7-20-1), stood out from the others, as they led to a higher predicted additive gain for the two evaluated traits. We concluded that the selection for production of snap beans and grains applying BLUP enabled the prediction and achievement of significant genetic gains for breeding snap beans for subsequent generations

Use of immature seed germination and single seed descent for rapid genetic gains in pigeonpea

AbstractLong duration required for generation advancement in pigeonpea [Cajanus cajan (L.) Millsp] is one of the major bottlenecks in realizing rapid genetic gains. Therefore, a technology for rapid generation turnover is warranted to facilitate the development of new cultivars and recombinant inbred lines. Breeding of early‐maturing cultivars has now opened up the possibility of rapid generation advance (RGA) in this crop. This paper reports the development of an RGA technology that integrates the germination of immature seeds with single seed descent method of breeding. The results showed that immature 35‐day‐old seeds can be used successfully to turn over a generation of pigeonpea with 100% seed germination. These way 3/4 successive generations can be grown within a year. The methodology presented in this study will accelerate the breeding process for breeding cultivars and develop rapidly the materials required for genomics research in pigeonpea.

Development of a High-Efficient Mutation Resource with Phenotypic Variation in Hexaploid Winter Wheat and Identification of Novel Alleles in the TaAGP.L-B1 Gene.

Mutated genetic resources play an important role in gene/allele characterization. Currently, there are few hexaploid winter wheat mutated resources available. Here, we developed a hexaploid winter wheat resource by inducing mutations via EMS treatment by the single seed descent method. A broad mutation spectrum with high mutation frequency (∼19%) on phenotypic variations was identified. These mutations included spike, leaf and seed morphology, plant architecture, and heading date variations. To evaluate the efficiency of the resource for reverse genetic analysis, allelic variations in the TaAGP.L-B1 gene, encoding the AGPase large subunit, were screened by the TILLING approach. Four missense mutations were identified and one allele in line E3-1-3, resulted in an amino acid change predicated to have severe effects on gene function. The other three mutations were predicted to have no effect. Results of gene expression patterns and grain starch content demonstrated that the novel allele in E3-1-3 altered the function of TaAGP.L-B1. Our results indicated that this mutated genetic wheat resource contained broad spectrum phenotypic and genotypic variations, that may be useful for wheat improvement, gene discovery, and functional genomics.

Genetic analysis for fruit biochemical traits (capsaicinoids and carotenoids) and dry fruit yield in chilli (Capsicum annuum L.)

Ten parental lines diverse in fruit biochemical traits were crossed in a half-diallel mating design to produce 45F1 hybrids. A total of 55 genotypes were evaluated for fruit biochemical traits and dry fruit yield to determine the mode of gene action, extent of heterosis, and combining abilities that facilitate in designing the best strategy for breeding peppers for industrial use. Different proportions of hybrids with positive to negative heterosis were obtained for different traits. The IHR3849×IHR3448F1 hybrid showed high standard heterosis for dry fruit yield per plant (35.42%**) and total capsaicinoid content (13.75%**). Estimates of combining ability effects showed that IHR500, IHR2451, and IHR4516 were the most suitable parents for developing hybrids for dry products processing industries. Both additive and dominance components were found significant in controlling the biochemical traits; the predominance of the additive effect was observed in capsaicinoids and dominance was observed for carotenoids. The results suggest that biparental mating, recurrent selection, single seed descent method, and heterosis breeding are the best approaches for breeding peppers for high carotenoids. Reciprocal recurrent selection at early stages is the best approach for breeding for a high dry pepper yield with high capsaicinoids.

Inheritance of Root Traits in an Interspecific Cross of Capsicum annuum × C. chinense in the Presence of Low Moisture

ABSTRACTProductivity of hot pepper (Capsicum annuum L.) is constrained when available moisture is not adequate. Capsicum genotypes with deep, strong roots enable plants to take up a higher volume of water when moisture is lacking, resulting in a more favorable plant water status. Little information is available on the genetic inheritance of root traits in peppers. The genetic components governing expression of root traits under low moisture were studied through six-generation mean analysis in an interspecific cross of IHR 3453 (Capsicum annuum) × IHR 4502 (C. chinense) of contrast root traits. The six generations (30 P1, 30 P2, 30 F1, 247 F2, 43 B1, and 47 B2) were developed and evaluated for root traits under low available moisture. Overall, root traits and shoot dry weight are complex in inheritance; additive and nonadditive components were important, indicating that reciprocal recurrent selection is the most effective breeding method for improving these traits. The dominance component (h) was highly significant and predominant in controlling most traits, except for root length. High heritability and high genetic advance over the mean indicate that selection is effective; however, it needs to be postponed to later generations. Recurrent selection, bulk pedigree, and single-seed descent methods were the most efficient strategies for improving root traits in Capsicum.

English

Genetic linkage maps provide a genomic framework for quantitative trait loci identification applied in marker assisted selection breeding in crops with limited resources. It serves as a powerful tool to breeders for analysing the mode of inheritance of genes of interest and monitoring of the transmission of target genes from parents to progeny. Single nucleotide polymorphism (SNP) markers have a great influence on mapping research studies: for faster development of new varieties of crops due to its abundance and high number of polymorphism. Thus, this research work aimed at constructing genetic linkage map of cowpea using SNP markers. This will facilitate development of new varieties of cowpea. Single seed descent method of breeding was used to generate mapping population between IT-95K-193-12 and Ife-Brown. Fresh leaves from both parental lines and F1 hybrids were genotyped with 135 SNP markers. Data from125 polymorphic SNP markers were used to construct linkage map. Results revealed 12 linkage maps with an average of 10 markers to a chromosome and average marker distance of 3.02 cM between the markers. Constructed map provides basic information that could assist in genetic improvement of cowpea, most especially in developing brown blotch resistant cowpea varieties through detection of quantitative trait loci (QTL) responsible for brown blotch resistance in cowpea when utilizing marker assisted selection method. Key words: Cowpea, genetic linkage map, single nucleotide polymorphism (SNP) markers, brown blotch resistance.

Registration of RTx430/Gaigaoliang Sorghum [Sorghum bicolor (L.) Moench] Recombinant Inbred Line Mapping Population

Sorghum [Sorghum bicolor (L.) Moench.] recombinant inbred line (RIL) mapping population RTx430 × Gaigaoliang (Reg. No. MP‐2, NSL 515993 MAP) was developed at the Plant Stress and Germplasm Development Unit, Cropping Systems Research Laboratory, USDA‐ARS, Lubbock, TX, and released in 2011 via the Germplasm Resources Information Network (GRIN). This population was developed to map early‐season field germinability, seedling vigor, and other important agronomic traits in sorghum and to serve as a long‐term genetic resource. The population is composed of 171 F7 RILs developed by single seed descent method and was evaluated at two locations for field emergence and seedling vigor at Lubbock and New Deal, TX, under early‐season planting (1 April) and under controlled conditions at 12°C. The genotype data for this population consist of 141 simple sequence repeat markers and 2922 single nucleotide polymorphism obtained through genotype‐by‐sequencing technology. Ten quantitative trait loci were detected for early‐season field germination and were used to identify early‐season cold‐tolerant recombinant inbreds with nonpigmented testa that can be used as pollinators in breeding programs.

Morphoagronomic characterization and genetic diversity of a common bean RIL mapping population derived from the cross Rudá x AND 277.

Recombinant inbred lines (RILs) are a valuable resource for building genetic linkage maps. The presence of genetic variability in the RILs is essential for detecting associations between molecular markers and loci controlling agronomic traits of interest. The main goal of this study was to quantify the genetic diversity of a common bean RIL population derived from a cross between Rudá (Mesoamerican gene pool) and AND 277 (Andean gene pool). This population was developed by the single seed descent method from 500 F2 plants until the F10 generation. Seven quantitative traits were evaluated in the field in 393 RILs, the parental lines, and five control cultivars. The plants were grown using a randomized block design with additional controls and three replicates. Significant differences were observed among the RILs for all evaluated traits (P < 0.01). A comparison of the RILs and parental lines showed significant differences (P < 0.01) for the number of days to flowering (DFL) and to harvest (DH), productivity (PROD) and mass of 100 beans (M100); however, there were no significant differences for plant architecture, degree of seed flatness, or seed shape. These results indicate the occurrence of additive x additive epistatic interactions for DFL, DH, PROD, and M100. The 393 RILs were shown to fall into 10 clusters using Tocher's method. This RIL population clearly contained genetic variability for the evaluated traits, and this variability will be crucial for future studies involving genetic mapping and quantitative trait locus identification and analysis.

Genetic potential of common bean progenies obtained by different breeding methods evaluated in various environments.

Grain yield is strongly influenced by the environment, has polygenic and complex inheritance, and is a key trait in the selection and recommendation of cultivars. Breeding programs should efficiently explore the genetic variability resulting from crosses by selecting the most appropriate method for breeding in segregating populations. The goal of this study was to evaluate and compare the genetic potential of common bean progenies of carioca grain for grain yield, obtained by different breeding methods and evaluated in different environments. Progenies originating from crosses between lines and CNFC 7812 and CNFC 7829 were replanted up to the F7 generation using three breeding methods in segregating populations: population (bulk), bulk within F2 progenies, and single-seed descent (SSD). Fifteen F8 progenies per method, two controls (BRS Estilo and Perola), and the parents were evaluated in a 7 x 7 simple lattice design, with plots of two 4-m rows. The tests were conducted in 10 environments in four States of Brazil and in three growing seasons in 2009 and 2010. Genetic parameters including genetic variance, heritability, variance of interaction, and expected selection gain were estimated. Genetic variability among progenies and the effect of progeny-environment interactions were determined for the three methods. The breeding methods differed significantly due to the effects of sampling procedures on the progenies and due to natural selection, which mainly affected the bulk method. The SSD and bulk methods provided populations with better estimates of genetic parameters and more stable progenies that were less affected by interaction with the environment.

Effectiveness of Breeding Methods for Production of Superior Genotypes and Maintenance of Genetic Variance in Faba Bean (Vicia faba, L.)

The present study was carried out during the period from 2007/ 08 to 2011/2012 at Agricultural Research Station, Faculty of Agriculture, Alexandria University, Alexandria, Egypt. The study aimed at evaluating the effectiveness of pedigree (P), single seed descent (SSD), and mass selection (MS) breeding methods. Two F2 populations, derived from two crosses, were used. Twenty families derived from each of the three breeding methods in each cross were tested for seed yield (t/ ha), seed yield per plant (g) and its components in F6 generation. A randomized complete block design with three replications was used. Significant differences existed, within F6 families of each cross, for seed yield, seed yield per plant and its components by applying either of the three methods. The widest range in seed yield was obtained by the SSD method. The SSD breeding method produced consistently more superior families in either and over the two crosses with 22, 19 and 18 families for (SSD), (P) and (MS) methods, respectively. The genotypic (2G) and phenotypic (2Ph) variances, for seed yield, estimated from SSD method were the highest compared with the other breeding methods over the two crosses. Heritability estimates, in broad sense, and expected genetic advance from selection for higher seed yield indicated that the SSD method recorded higher values (h2= 0.87-0.93, G= 0.51- 0.85) compared with the other two methods. Based on the obtained results, it seems that the SSD breeding method was more effective compared to the other two breeding methods, in producing superior genotypes in seed yield and maintaining genetic variance for further selection and improvement of that character. Considering the partial allogamous nature of the crop, it could be concluded that the SSD method was more efficient and could be less costly in breeding for high seed yield.

New trends in plant breeding - example of soybean

Soybean breeding and selection is a continual process designed to increase yield levels and improve resistance to biotic and abiotic stresses. Soybean breeders have been successful in producing a large number of varieties using conventional breeding methods, the Single Seed Descent method in particular. In recent decades, with the increased use of genetic transformations, backcrossing is more frequent though the only trait that has been commercialized is glyphosate tolerance. Physiological breeding poses a particular challenge, as well as phenotyping and development of useful criteria and techniques suitable for plant breeding. Using modern remote sensing techniques provides great opportunity for collecting a large amount of physiological data in real environment, which is necessary for physiological breeding. Molecular based plant breeding methods and techniques are a conceptual part of any serious breeding program. Among those methods, the most extensively used is marker-assisted selection, as a supplement to conventional breeding methods.

Registration of ‘NuMex 01’ High Oleic Valencia Peanut

‘NuMex 01’ (Reg. No. CV-123, PI 670460) is a high oleic Valencia peanut (Arachis hypogaea L. subsp. fastigiata var. fastigiata) cultivar, developed by the New Mexico Agricultural State University Experiment Station located at Clovis, NM, and released on 17 Sept. 2013. NuMex 01 originated from a cross made between ‘New Mexico Valencia A’ (NM Valencia A) and ‘Brantley’. NM Valencia A has predominantly three- to four-seeded pods, whereas Brantley has mostly two-seeded large virginia pods. Pedigree selection was practiced based on oil quality as determined by high oleic (O)/linoleic (L) fatty acid ratio, pod size and shape, seeds per pod, seed size, testa color, market type (Valencia), maturity, yield, and grade characteristics. The selected segregants with these characteristics were advanced by single-seed descent method until F4. Phenotypically uniform progenies were bulk harvested to conduct yield trials in F5. Performance tests in replicated trials across eastern New Mexico and west Texas began in 2010 and continued until 2012. NuMex 01 was tested under identity as NM083092. It matures in about 130 d, similar to the control cultivar, NM Valencia A. Averaged across 15 season-locations, NuMex 01 produced 13% higher pod yield and showed 4% greater 100-seed weight than NM Valencia A (average pod yield 3068 kg ha−1; 100 seed weight 46.5 g). NuMex 01 is the first high oleic (O/L ratio 23.3 compared with 1.1 in NM Valencia A) Valencia peanut cultivar released for cultivation in eastern New Mexico and west Texas. NuMex 01 has good roasted flavor attributes.

Recurrent breeding method enhances the level of blackspot (Didymella pinodes (Berk. &amp; Blox.) Vestergr.) resistance in field pea (Pisum sativum L.) in southern Australia

AbstractBlackspot, caused by Didymella pinodes (Berk. &amp; Blox.)Vestergr., is one of the most important diseases of field pea, causing significant reduction in seed yield and quality in southern Australia and in other parts of the world. Development of resistant germplasm has been slow because of the low level of resistance found in the available germplasm, poor reliability of screening methods and the polygenic nature of inheritance. Crosses were made between agronomically suitable lines and resistant germplasm from different sources. Their progeny were advanced through the single seed descent method and single plants were selected at F4/F5. The F4/F5 derived lines were screened against blackspot in the field under disease pressure and evaluated for grain yield at multilocations over 2 years. Despite the low level of resistance in the parental germplasm, the level of resistance has increased significantly in the new germplasm. Many of the resistant lines were late and low yielding, but lines with higher resistance and early flowering and high yield potential were also identified indicating that the disease resistance, adaptation and yield potential can be combined. However, the resistance identified in this study is only partial and suitable agronomic practices may need to be supplemented to minimise the yield loss and enhance the benefits of this partial resistance.